linux内核：systemtap内核调试 例子

http://www.sourceware.org/systemtap/examples/

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All 124 Examples

• ¶ general/alias_suffixes.stp - Count I/O Syscalls using Alias Suffixes
  keywords: IO STATISTICS 
  

  alias_suffixes.stp is a demonstration of how alias suffixes in the systemtap language might be used. The script tracks the wall clock time for each invocation of the system calls open, close, read, and write. When the script exists it prints out the minimum, average, and maximum times in microseconds for each system call, followed by a count of times that each syscall was invoked and a histogram showing the distributions of times.

  # stap alias_suffixes.stp -c "sleep 1"

• ¶ general/ansi_colors.stp - Color Table for ansi_set_color2() and ansi_set_color3()
  keywords: FORMAT 
  

  The script prints a table showing the available color combinations for the ansi_set_color2() and ans_set_color3() functions in the ansi.stp tapset.

  # stap ansi_colors.stp

• ¶ general/ansi_colors2.stp - Show Attribues in Table for ansi_set_color3()
  keywords: FORMAT 
  

  The script prints a table showing the available attributes (bold, underline, and inverse) with color combinations for the ans_set_color3() function in the ansi.stp tapset.

  # stap ansi_colors2.stp

• ¶ general/badname.stp - Bad Filename Filter
  keywords: FILESYSTEM GURU 
  

  The badname.stp script shows how one could prevent the creation of files with undesirable names using guru mode.

  # stap -g badname.stp -c "touch /tmp/myXXXbadnameXXXfile.$$ 2>&1 | grep \denied"

• ¶ general/eventcount.stp - Count Specified Events
  keywords: STATISTICS THREAD PROCESS 
  

  The script periodically prints a count of specified events and their related tid's over the course of execution. Numerous configuration options exist to control filtering / reporting, see the script source.

  # stap eventcount.stp syscall.* -c 'sleep 1'

• ¶ general/func_time_stats.stp - Function Time Statistics
  keywords: FUNCTION STATISTICS 
  

  The func_time_stats.stp script tracks the wall clock time for each invocation of the function probe listed as the first command line argument. When the script exits it prints out the minimum, average, and maximum times in microseconds followed by a count of times that the function was called and a histogram showing the distributions of times.

  # stap func_time_stats.stp 'syscall.nanosleep' -c "sleep 1"

• ¶ general/graphs.stp - Graphing Disk and CPU Utilization
  keywords: DISK CPU UTILIZATION 
  

  The script tracks the disk and CPU utilization. The resulting output of the script can be piped into gnuplot to generate a graph of disk and CPU USE.

  # stap graphs.stp -c "sleep 1"

• ¶ general/helloworld.stp - SystemTap "Hello World" Program
  keywords: SIMPLE 
  

  A basic "Hello World" program implemented in SystemTap script. It prints out "hello world" message and then immediately exits.

  # stap helloworld.stp

• ¶ general/para-callgraph-verbose.stp - Callgraph Tracing with Verbose Arguments
  keywords: TRACE CALLGRAPH 
  

  Print a timed per-thread microsecond-timed callgraph, complete with pretty-printed function parameters and return values. The first parameter names the function probe points to trace. The optional second parameter names the probe points for trigger functions, which acts to enable tracing for only those functions that occur while the current thread is nested within the trigger.

  # stap para-callgraph-verbose.stp 'kernel.function("*@fs/proc*.c")' \'kernel.function("vfs_read")' -c "cat /proc/sys/vm/* || true"

• ¶ general/para-callgraph.stp - Callgraph Tracing with Arguments
  keywords: TRACE CALLGRAPH 
  

  Print a timed per-thread microsecond-timed callgraph, complete with function parameters and return values. The first parameter names the function probe points to trace. The optional second parameter names the probe points for trigger functions, which acts to enable tracing for only those functions that occur while the current thread is nested within the trigger.

  # stap para-callgraph.stp 'kernel.function("*@fs/proc*.c")' \'kernel.function("vfs_read")' -c "cat /proc/sys/vm/* || true"

• ¶ general/py2example.stp - SystemTap python 2 support tapset
  keywords: SIMPLE 
  

  A python support tapset that displays backtraces and variable values

  # stap -I tapset -c '/usr/bin/python2 pyexample.py 35' py2example.stp

• ¶ general/py3example.stp - SystemTap python 3 support tapset
  keywords: SIMPLE 
  

  A python support tapset that displays backtraces and variable values

  # stap -g --suppress-time-limits -I tapset -c '/usr/bin/python3 \pyexample.py 35' py3example.stp

• ¶ general/regex.stp - Report opened files whose names match a given regex
  keywords: REGEX 
  

  Uses the regex functionality to detect opened files whose names match a pattern given on the command line. If no command line parameter is given, demonstrate by filtering for files that end with an extension showing them to be an archive.

  # stap regex.stp -c "sleep 1"

• ¶ general/sizeof.stp - Print the Size of a C Type
  keywords: STATISTICS MEMORY 
  

  This script prints the size of a type, based on dwarf debuginfo for any kernel or userspace module, or trial-compilation of a given header file name.

  # stap sizeof.stp FILE '</usr/include/stdio.h>'

• ¶ general/stopwatches.stp - See the amount of wall clock time a process spends in various states
  keywords: TIME 
  

  The stopwatch.stp script illustrates how to use multiple stopwatches record how much wallclock time a process spends in kernel- and user-space. On exit the script prints out the time in seconds, milliseconds, microseconds, and nanoseconds. Note that this output of this script is not directly comparable to the time command because time records the time that the process is actually active in kernel- and user-space.

  # stap stopwatches.stp -c "sleep 1"

• ¶ general/varwatch.stp - Watch a Variable Changing Value in a Thread
  keywords: MONITORING 
  

  This script places a set of probes (specified by $1), each of which monitors the state of some context $variable expression (specified by $2). Whenever the value changes, with respect to the active thread, the event is traced.

  # stap -w varwatch.stp 'kernel.statement("do_sys_open@fs/open.c:*")' \'$$vars' -c "sleep 1"

• ¶ general/watchdog.stp - Watchdog Timer for Arbitrary Events
  keywords: WATCHDOG BACKTRACE 
  

  The watchdog.stp script provides a watchdog timer mechanism for arbitrary events. The script takes three arguments: the events to start watchdog timer, the event to stop the watchdog timer, and the time in millseconds for the watchdog. If the watchdog timer is exceed, the script will trigger a stack backtrace of the user-process that timed out using pstack. This script can be used to diagnose what the userspace application is doing when a slower than expected operation occurs.

  # stap watchdog.stp 'syscall.nanosleep' 'syscall.nanosleep.return' 1000 \-c "sleep 1"

• ¶ interrupt/interrupts-by-dev.stp - Record Interrupts on a Per-Device Basis
  keywords: INTERRUPT 
  

  The interrupts-by-dev.stp script profiles interrupts received by each device per 100 ms.

  # stap interrupts-by-dev.stp -c "sleep 1"

• ¶ interrupt/scf.stp - Tally Backtraces for Inter-Processor Interrupt
  keywords: INTERRUPT BACKTRACE 
  

  The Linux kernel function smp_call_function causes expensive inter-processor interrupts (IPIs). The scf.stp script tallies the processes and backtraces causing the interprocessor interrupts to identify the cause of the expensive IPI. On exit the script prints the tallies in descending frequency.

  # stap scf.stp -c "sleep 1"

• ¶ io/deviceseeks.stp - Histograms of Seek Behavior for Each Device
  keywords: DISK 
  

  The deviceseeks.stp script generates a histogram showing the frequency of different sized seeks (in sectors) on each device.

  # stap deviceseeks.stp -c "sleep 1"

• ¶ io/disktop.stp - Summarize Disk Read/Write Traffic
  keywords: DISK 
  

  Get the status of reading/writing disk every 5 seconds, output top ten entries during that period.

  # stap disktop.stp -c "sleep 1"

• ¶ io/eatmydata.stp - disable fsync
  keywords: IO GURU SIMPLE 
  

  Suppresses fsync() syscalls from processes identified by stap -c/-x by turning them into presumed-faster fsync() on file descriptor 1 (stdout).

  # stap -g eatmydata.stp -c 'strace ls || true'

• ¶ io/enospc.stp - Report an disk out-of-space condition.
  keywords: DISK FILESYSTEM 
  

  This script monitors a filesystem implementations for early internal indications of ENOSPC, and reports these to the system logger and the systemtap console.

  # stap enospc.stp -c "sleep 1"

• ¶ io/inodewatch.stp - Monitoring Reads and Writes to a File
  keywords: IO 
  

  The inodewatch.stp outputs the executable name and process id each time a read or write occurs to the specified inode on the specified major/minor device.

  # stap inodewatch.stp 0x08 0x01 100 -c "sleep 1"

• ¶ io/inodewatch2.stp - Monitoring Attribute Changes to a File
  keywords: IO 
  

  The inodewatch2.stp script outputs the executable name, process id, and attributes each time the attributes are changed on the specified inode on the specified major/minor device.

  # stap inodewatch2.stp 0x08 0x01 100 -c "sleep 1"

• ¶ io/io_submit.stp - Tally Reschedule Reason During AIO io_submit Call
  keywords: IO BACKTRACE 
  

  When a reschedule occurs during an AIO io_submit call, accumulate the traceback in a histogram. When the script exits prints out a sorted list from most common to least common backtrace.

  # stap io_submit.stp -c "sleep 1"

• ¶ io/ioblktime.stp - Average Time Block IO Requests Spend in Queue 
  keywords: IO 
  

  The ioblktime.stp script tracks the amount of time that each block IO requests spend waiting for completion. The script computes the average waiting time for block IO per device and prints list every 10 seconds. In some cases there can be too many outstanding block IO operations and the script may exceed the default number of MAXMAPENTRIES allowed. In this case the allowed number can be increased with "-DMAXMAPENTRIES=10000" option on the stap command line.

  # stap ioblktime.stp -c "sleep 1"

• ¶ io/iodevstats.stp - List Executables Reading and Writing the Most Data by Device
  keywords: IO PROFILING 
  

  The iodevstats.stp script measures the amount of data successfully read and written by all the executables for each io device on the system. The output is sorted from greatest sum of bytes read and written to a device by an executable to the least. The output contains device major/minor number, the count of operations (reads and writes), the totals and averages for the number of bytes read and written.

  # stap iodevstats.stp -c "sleep 1"

• ¶ io/iostat-scsi.stp - IO Statistics for SCSI Devices
  keywords: IO PROFILING SCSI 
  

  The iostat-scsi.stp script provides a breakdown of the number of blks read and written on the machine's various SCSI devices. The script takes one argument which is the number of seconds between reports.

  # stap -g iostat-scsi.stp 1 -c "sleep 1"

• ¶ io/iostats.stp - List Executables Reading and Writing the Most Data
  keywords: IO PROFILING 
  

  The iostat.stp script measures the amount of data successfully read and written by all the executables on the system. The output is sorted from most greatest sum of bytes read and written by an executable to the least. The output contains the count of operations (opens, reads, and writes), the totals and averages for the number of bytes read and written.

  # stap iostats.stp -c "sleep 1"

• ¶ io/iotime.stp - Trace Time Spent in Read and Write for Files 
  keywords: PROFILING SYSCALL IO FILE 
  

  The script watches each open, close, read, and write syscalls on the system. For each file the scripts observes opened it accumulates the amount of wall clock time spent in read and write operations and the number of bytes read and written. When a file is closed the script prints out a pair of lines for the file. Both lines begin with a timestamp in microseconds, the PID number, and the executable name in parentheses. The first line with the "access" keyword lists the file name, the attempted number of bytes for the read and write operations. The second line with the "iotime" keyword list the file name and the number of microseconds accumulated in the read and write syscalls.

  # stap iotime.stp -c "sleep 1"

• ¶ io/iotop.stp - Periodically Print IO Activity by Process Name
  keywords: IO 
  

  Every five seconds print out the top ten executables generating I/O traffic during that interval sorted in descending order.

  # stap iotop.stp -c "sleep 1"

• ¶ io/mbrwatch.stp - Monitor Read/Write of the Boot Sector Area of Block Devices
  keywords: IO MONITORING DISK 
  

  The mbrwatch.stp script reports any attempted reads/writes of the first few sectors of a raw block device.

  # stap mbrwatch.stp -c "dd of=/dev/null count=1 if=/dev/`grep -v major \/proc/partitions | grep . | awk '{print $4}' | head -1`"

• ¶ io/nfs_func_users.stp - Tally the Number of NFS Functions Used by Each Process
  keywords: IO PROFILING 
  

  The nfs_func_users.stp script counts the uses of NFS functions in the kernel on a per process bases. The output is sorted from the process with the greatest number of NFS functions called to the least. The output contains the executable name, the process number, and the total number of NFS functions called by the process.

  # stap nfs_func_users.stp -c "sleep 1"

• ¶ io/traceio.stp - Track Cumulative IO Activity by Process Name
  keywords: IO 
  

  Every second print out the top ten executables sorted in descending order based on cumulative I/O traffic observed.

  # stap traceio.stp -c "sleep 1"

• ¶ io/traceio2.stp - Watch IO Activity on a Particular Device
  keywords: IO 
  

  Print out the executable name and process number as reads and writes to the specified device occur.

  # stap traceio2.stp 0x0801 -c "sleep 1"

• ¶ io/ttyspy.stp - Monitor TTY Typing
  keywords: IO TTY MONITORING GURU 
  

  The ttyspy.stp script uses tty_audit hooks to monitor recent typing activity on the system, printing a scrolling record of recent keystrokes, on a per-tty basis.

  # stap --skip-badvars -g ttyspy.stp -c "sleep 1"

• ¶ locks/bkl.stp - Tracing Contention on Big Kernel Lock
  keywords: LOCKING 
  

  The bkl.stp script can help determine whether the Big Kernel Lock (BKL) is causing serialization on a multiprocessor system due to excessive contention of the BKL. The bkl.stp script takes one argument which is the number of processes waiting for the Big Kernel Lock (BKL). When the number of processes waiting for the BKL is reached or exceeded, the script will print a time stamp, the number of processes waiting for the BKL, the holder of the BKL, and the amount of time the BKL was held.

  # stap bkl.stp -c "sleep 1" 1

• ¶ locks/bkl_stats.stp - Per Process Statistics on Big Kernel Lock Use
  keywords: LOCKING 
  

  The bkl_stats.stp script can indicate which processes have excessive waits for the Big Kernel Lock (BKL) and which processes are taking the BKL for long periods of time. The bkl_stats.stp script prints lists of all the processes that require the BKL. Every five seconds two tables are printed out. The first table lists the processes that waited for the BKL followed by the number of times that the process waited, the minimum time of the wait, the average and the maximum time waited. The second table lists has similar information for the time spent in holding the lock for each of the processes.

  # stap bkl_stats.stp -c "sleep 1"

• ¶ memory/hw_watch_addr.stp - Watch a Kernel Address Using Breakpoint Hardware
  keywords: MEMORY WATCHPOINT 
  

  The script will watch accesses to a single kernel address and prints a traceback each time the address is accessed. This script needs to be run as root to allow access to the breakpoint hardware.

  # stap --all-modules hw_watch_addr.stp 0x`grep "vm_dirty_ratio" \/proc/kallsyms` -c "sleep 5"

• ¶ memory/hw_watch_sym.stp - Watch a Kernel Symbol Using Breakpoint Hardware
  keywords: MEMORY WATCHPOINT 
  

  The script will watch accesses to the starting address of a single kernel symbol and prints a traceback each time the symbol is accessed. This script needs to be run as root to allow access to the breakpoint hardware.

  # stap --all-modules hw_watch_sym.stp vm_dirty_ratio -c "sleep 5"

• ¶ memory/kmalloc-top - Show Paths to Kernel Malloc Invocations
  keywords: MEMORY 
  

  The kmalloc-top perl program runs a small systemtap script to collect stack traces for each call to the kmalloc function and counts the time that each stack trace is observed. When kmalloc-top exits it prints out sorted list. The output can be filtered to print only the first N stack traces (-t), stack traces with a minimum counts (-m), or exclude certain stack traces (-e).

  # ./kmalloc-top -c "sleep 1"

• ¶ memory/last_100_frees.stp - Log recent free(3) calls.
  keywords: MEMORY PROCESS BACKTRACE 
  

  This script reports on the last few free(3) libc calls done by processes (possibly restricted by stap -x/-c), along with a userspace backtrace at those moments.

  # stap last_100_frees.stp -c "stap -V" -d `which stap` --ldd

• ¶ memory/mmanonpage.stp - Track Virtual Memory System Actions on Anonymous Pages
  keywords: MEMORY 
  

  The mmanonpage.stp script uses the virtual memory tracepoints available in some kernels to track the number of faults, user space frees, page ins, copy on writes and unmaps for anonymous pages. When the script is terminated the counts are printed for each process that allocated pages while the script was running. This script displays the anonymous page statistics for each process that ran while the script is active. It's useful in debugging leaks in the anonymous regions of a process.

  # stap mmanonpage.stp -c "sleep 1"

• ¶ memory/mmfilepage.stp - Track Virtual Memory System Actions on File Backed Pages
  keywords: MEMORY 
  

  The mmfilepage.stp script uses the virtual memory tracepoints available in some kernels to track the number of faults, copy on writes mapping, and unmapping operations for file backed pages. When the script is terminated the counts are printed for each process that allocated pages while the script was running. The mmfilepage.stp script is useful in debugging leaks in the mapped file regions of a process.

  # stap mmfilepage.stp -c "sleep 1"

• ¶ memory/mmreclaim.stp - Track Virtual Memory System Page Reclamation
  keywords: MEMORY 
  

  The mmreclaim.stp script uses the virtual memory tracepoints available in some kernels to track page reclaim activity that occurred while the script was running. It's useful in debugging performance problems that occur due to page reclamation.

  # stap mmreclaim.stp -c "sleep 1"

• ¶ memory/mmwriteback.stp - Track Virtual Memory System Writing to Disk
  keywords: MEMORY 
  

  The mmwriteback.stp script uses the virtual memory tracepoints available in some kernels to report all of the file writebacks that occur form kupdate, pdflush and kjournald while the script is running. It's useful in determining where writes are coming from on a supposedly idle system that is experiencing unexpected IO.

  # stap mmwriteback.stp -c "sleep 1"

• ¶ memory/numa_faults.stp - Summarize Process Misses across NUMA Nodes
  keywords: MEMORY NUMA 
  

  The numa_faults.stp script tracks the read and write pages faults for each process. When the script exits it prints out the total read and write pages faults for each process. The script also provide a break down of page faults per node for each process. This script is useful for determining whether the program has good locality (page faults limited to a single node) on a NUMA computer.

  # stap numa_faults.stp -c "sleep 1"

• ¶ memory/overcommit.stp - Log Failed Process Memory Allocation Due to Overcommit Limits
  keywords: MEMORY LIMITS 
  

  The overcommit.stp script prints a line each time the kernel refuses a memory allocation request from a process because of /proc/sys/vm/overcommit* limits.

  # stap overcommit.stp -c "sleep 1"

• ¶ memory/pfaults.stp - Generate Log of Major and Minor Page Faults
  keywords: MEMORY 
  

  The pfaults.stp script generates a simple log for each major and minor page fault that occurs on the system. Each line contains a timestamp (in microseconds) when the page fault servicing was completed, the pid of the process, the address of the page fault, the type of access (read or write), the type of fault (major or minor), and the elapsed time for page fault. This log can be examined to determine where the page faults are occurring.

  # stap pfaults.stp -c "sleep 1"

• ¶ memory/vm.tracepoints.stp - Collect Slab Allocation Statistics
  keywords: MEMORY SLAB STATISTICS 
  

  The script will probe all memory slab/slub allocations and collects information about the size of the object (bytes requested) and user-space process in execution. When run over a period of time, it helps to correlate kernel-space memory consumption owing to user-space processes.

  # stap vm.tracepoints.stp -c "sleep 10"

• ¶ network/autofs4.stp - Watch autofs4 Operations
  keywords: NETWORK AUTOFS NFS 
  

  Trace key autofs4 operations such as mounting or unmounting remote filesystems.

  # stap autofs4.stp -c "sleep 1"

• ¶ network/connect_stat.stp - Show Process Ancestry for IP Connections
  keywords: NETWORK SOCKET PROCESS 
  

  The connect_stat.stp script prints a task's entire ancestry (parent process name/uid/gid) whenever it attempts an outgoing socket connection to a given IP address.

  # stap connect_stat.stp 127.0.0.1 -c "sleep 1"

• ¶ network/dropwatch.stp - Watch Where Socket Buffers Are Freed in the Kernel
  keywords: NETWORK TRACEPOINT SOCKET 
  

  Every five seconds the dropwatch.stp script lists the number of socket buffers freed at locations in the kernel.

  # stap dropwatch.stp -c "sleep 1"

• ¶ network/netdev.stp - Trace Activity on Network Devices
  keywords: NETWORK DEVICE TRAFFIC 
  

  The netdev.stp script traces configuration and transmit/receive activity on network devices.

  # stap netdev.stp -c "sleep 1"

• ¶ network/netfilter_drop.stp - System-Wide Network Packet Dropping Tool
  keywords: NETWORK PACKETS GURU 
  

  The script drops the specified number of packets of the specified protocol. Valid protocols are TCP, UDP, or ALL. If ALL is specified, all incoming packets are dropped. The number of packets to drop can be specified with a positive integer. A value of 0 indicates that packets should be dropped until the user manually exits.

  # stap -g netfilter_drop.stp TCP 1 -c "sleep 2"

• ¶ network/netfilter_summary.stp - System-Wide Count of Network Packets by IPs
  keywords: NETWORK TRAFFIC 
  

  The script watches all IPv4 network traffic on the system. On exit the script prints a list showing the number of packets sent along source IP address / destination IP address pair encountered, and the total number of bytes sent among the pair. The list is ordered from greatest to least number of packets seen among the source/destination pairs.

  # stap netfilter_summary.stp -c "sleep 1"

• ¶ network/nettop.stp - Periodic Listing of Processes Using Network Interfaces
  keywords: NETWORK TRAFFIC 
  

  Every five seconds the nettop.stp script prints out a list of processed (PID and command) with the number of packets sent/received and the amount of data sent/received by the process during that interval.

  # stap nettop.stp -c "sleep 1"

• ¶ network/nfsd-recent.stp - Keep track of NFS server statistics
  keywords: NFS STATISTICS 
  

  This script tracks all nfsd server operations by client_ip address, and periodically lists those clients that have made recent requests. It's a way of finding out which nfs clients might be considered still connected.

  # stap nfsd-recent.stp -c "sleep 1"

• ¶ network/nfsd_unlink.stp - Find Which Client Is Removing NFS Files on Server
  keywords: NFS DISK 
  

  The nfsd_unlink.stp script lists the ip address and file name each time time a file is being removed or unlinked by the nfsd. This script is run on the nfs server.

  # stap nfsd_unlink.stp -c "sleep 1"

• ¶ network/nfsdtop.stp - Keep track of NFS server statistics
  keywords: NFS STATISTICS 
  

  The nfsdtop.stp script gathers and displays NFS lookups,

  # stap nfsd_unlink.stp -c "sleep 1"

• ¶ network/sk_stream_wait_memory.stp - Track Start and Stop of Processes Due to Network Buffer Space
  keywords: NETWORK TCP PROCESS 
  

  The sk_stream-wait_memory.stp prints a time stamp, executable, and pid each time a process blocks due to the send buffer being full. A similar entry is printed each time a process continues because there is room in the buffer.

  # stap sk_stream_wait_memory.stp -c "sleep 1"

• ¶ network/socket-trace.stp - Trace Functions Called in Network Socket Code
  keywords: NETWORK SOCKET 
  

  The script instruments each of the functions in the Linux kernel's net/socket.c file. The script prints out trace data. The first element of a line is time delta in microseconds from the previous entry. This is followed by the command name and the PID. The "->" and "<-" indicates function entry and function exit, respectively. The last element of the line is the function name.

  # stap socket-trace.stp -c "sleep 1"

• ¶ network/socktop - Periodically Summarize Socket Activity on the System
  keywords: NETWORK SOCKET 
  

  The socktop script periodically prints out a list of the processes with the highest socket activity. Command line options for the script allow filtering to focus on particular types of sockets. The "-h" option lists socktop script's filtering options.

  # ./socktop -c 1

• ¶ network/tcp_connections.stp - Track Creation of Incoming TCP Connections
  keywords: NETWORK TCP SOCKET 
  

  The tcp_connections.stp script prints information for each new incoming TCP connection accepted by the computer. The information includes the UID, the command accepting the connection, the PID of the command, the port the connection is on, and the IP address of the originator of the request.

  # stap tcp_connections.stp -c "sleep 1"

• ¶ network/tcp_init_cwnd.stp - Increase Initial TCP Congestion Window to 10
  keywords: NETWORK TCP SOCKET GURU 
  

  Run the tcp_init_cwnd.stp script in the background to override a kernel's default tcp cwnd value to 10, which has been found to improve latency for web server type workloads. The script prints a count of cwnd value changes when it is stopped.

  # stap -g tcp_init_cwnd.stp -c "sleep 1"

• ¶ network/tcp_trace.stp - TCP Connection Tracing Utility
  keywords: NETWORK TRACE 
  

  This scripts traces a given TCP connection based on the filter parameters given by the user. The indexing is done by the 4 tuples local address, remote address, local port, remote port.

  # stap tcp_trace.stp 127.0.0.1:*-127.0.0.1:* timeout=1

• ¶ network/tcpdumplike.stp - Dump of Received UDP/TCP Packets
  keywords: NETWORK TRAFFIC 
  

  The tcpdumplike.stp prints out a line for each TCP & UDP packet received. Each line includes the source and destination IP addresses, the source and destination ports, and flags.

  # stap tcpdumplike.stp -c "sleep 1"

• ¶ network/tcpipstat.stp - Display Network Statistics for Individual TCP Sockets
  keywords: NETWORK STATISTICS 
  

  The tcpipstat script collects and displays network statistics related to individual TCP sockets or groups of sockets. The statistics that are collected are simular to that of the command netstat -s, only sorted and grouped by individual sockets.

  # stap tcpipstat.stp timeout=1

• ¶ process/auditbt.stp - Generate backtraces for kernel audit events
  keywords: MONITORING SECURITY AUDIT BACKTRACE 
  

  Attaches to the kernel audit-log paths (also used by libaudit), and log every record being sent, along with a user-space backtrace of the process that caused it.

  # stap auditbt.stp -d /usr/bin/sudo --ldd -c "sudo true"

• ¶ process/chng_cpu.stp - Monitor Changes in Processor Executing a Task
  keywords: SCHEDULER 
  

  The chng_cpu.stp script takes an argument which is the executable name of the task it should monitor. Each time a task with that executable name is found running on a different processor, the script prints out the thread id (tid), the executable name, the processor now running the task, the thread state, and a backtrace showing the kernel functions that triggered the running of the task on the processor.

  # stap chng_cpu.stp -c "sleep 1" bash

• ¶ process/cycle_thief.stp - Track IRQ's and Other Processes Stealing Cycles from a Task
  keywords: PROCESS SCHEDULER TIME TRACEPOINT INTERRUPT 
  

  The cycle_thief.stp script instruments the scheduler and IRQ handler to determine which processes and interrupts are competing with the specified task for the cpu cycles. This script uses the '-c' or '-x' options to focus on a specific task. The script output the number of times the task migrates between processors, histograms showing the length of time on and off processor, lists of processes running while the task is off the processor, and the interrupts that occurred while the task was running.

  # stap cycle_thief.stp -c "sleep 1"

• ¶ process/errsnoop.stp - Tabulate System Call Errors
  keywords: PROCESS SYSCALL 
  

  Prints a periodic tabular report about failing system calls, by process and by syscall failure. The first optional argument specifies the reporting interval (in seconds, default 5); the second optional argument gives a screen height (number of lines in the report, default 20).

  # stap errsnoop.stp 1 10 -c "sleep 1"

• ¶ process/forktracker.stp - Trace Creation of Processes
  keywords: PROCESS SCHEDULER 
  

  The forktracker.stp script prints out a time-stamped entry showing each fork and exec operation on the machine. This can be useful to determine what process is creating a flurry of short-lived processes.

  # stap forktracker.stp -c "sleep 1"

• ¶ process/futexes.stp - System-Wide Futex Contention
  keywords: SYSCALL LOCKING FUTEX 
  

  The script watches the futex syscall on the system. On exit the futex's address, the number of contentions, and the average time for each contention on the futex are printed from lowest pid number to highest.

  # stap futexes.stp -c "sleep 1"

• ¶ process/futexes2.stp - System-Wide Shared Futex Contention
  keywords: SYSCALL LOCKING FUTEX 
  

  The script watches just shared futex syscalls on the system. On exit the futex's key, the number of contentions, and the average time for each contention on the futex are printed from lowest pid number to highest.

  # stap futexes2.stp -c "sleep 1"

• ¶ process/ltrace.stp - uprobes-based ltrace
  keywords: PROCESS 
  

  The ltrace.stp script lists calls that the designated process makes through PLTs (procedure linkage tables), generally into shared libraries.

  # stap ltrace.stp -c ls || echo PR14738

• ¶ process/migrate.stp - Track the Migration of Specific Executables
  keywords: SCHEDULER 
  

  The migrate.stp script takes an argument which is the executable name of the task it should monitor. Each time a task with that executable name migrates between processors an entry is printed with the process id (pid), the executable name, the processor off loading the task, and the process taking the task. Note that the task may or may not be executing at the time of the migration.

  # stap migrate.stp -c "sleep 1" bash

• ¶ process/mutex-contention.stp - pthread mutex contention analysis
  keywords: LOCKING 
  

  Tracks pthread-mutex initialization/use and underlying futex operations, to identify (with backtraces/symbol-names) the mutexes suffering most contention. Invoke with "-d SHLIB --ldd", perhaps with -DMAXMAPENTRIES=NNNN for some large NNNN, if the arrays overflow due to heavy activity.

  # stap mutex-contention.stp -c "sleep 1"

• ¶ process/noptrace.stp - Disable ptrace from Hierarchies of Processes
  keywords: PROCESS SECURITY GURU 
  

  Blocks ptrace(2) attempts from processes identified by stap -c/-x, as also specifiable from /proc/systemtap/stap_XXX/ control files. Processes may be added or removed from the blocked list.

  # stap -g noptrace.stp -c 'strace ls || true'

• ¶ process/pfiles.stp - Print Process File Descriptors
  keywords: PROCESS FILE 
  

  Run pfiles.stp to produce a human-readable summary of all open file descriptors of a given process. Specify the process-id as -x PID for fastest performance.

  # stap -g pfiles.stp -x $$

• ¶ process/plimit.stp - Print Resource Limits of Process
  keywords: PROCESS 
  

  The script prints a variety of resource limits for a given pid, like /proc/$$/limits on recent kernels.

  # stap -g plimit.stp $$

• ¶ process/procmod_watcher.stp - Monitor process creation/termination and module [un]loading
  keywords: PROCESS MONITORING SYSCALL TRACEPOINT 
  

  The procmod_watcher.stp script monitors calls to fork(), exec(), exit(), init_module(), and delete_module(). Event-specific details are also printed out (e.g. for exec(), the file being exec'ed). This script does not require debuginfo.

  # stap procmod_watcher.stp -c "sleep 1"

• ¶ process/psig.stp - Print Process File Descriptors
  keywords: PROCESS SIGNALS 
  

  Run psig.stp to produce a human-readable summary of the signal handling configuration of a given process. Specify the process-id as -x PID for fastest performance.

  # stap -DMAXACTION=10000 -g psig.stp -x $$

• ¶ process/pstrace_exec.stp - Print trace of process ancestors for matching exec commands
  keywords: PROCESS BACKTRACE 
  

  The pstrace_exec.stp script watches each exec operation. If the exec contains a substring that matches the script's command-line argument, it prints out that process and all of its ancestors.

  # stap pstrace_exec.stp -c "sleep 1" bash

• ¶ process/pstree.stp - Generates a process diagram in DOT form.
  keywords: PROCESS DIAGRAM 
  

  The pstree.stp script generates a process diagram in DOT form. For instance, it may be useful on a 'make' command to see all the processes that are started.

  # stap pstree.stp -c "sleep 1"

• ¶ process/rlimit_nofile.stp - Trace processes running out of file descriptors 
  keywords: LIMITS 
  

  This script watches processes being scheduled and which try to allocate a file descriptor without luck.

  # stap rlimit_nofile.stp -c "sleep 1"

• ¶ process/schedtimes.stp - Track Time Processes Spend in Various States Using Tracepoints
  keywords: PROCESS SCHEDULER TIME TRACEPOINT 
  

  The schedtimes.stp script instruments the scheduler to track the amount of time that each process spends in running, sleeping, queuing, and waiting for io. On exit the script prints out the accumulated time for each state of processes observed. Optionally, this script can be used with the '-c' or '-x' options to focus on a specific PID and its children.

  # stap schedtimes.stp -c "sleep 1"

• ¶ process/semop-watch.stp - Watch semop(2)/semtimedop(2) operations
  keywords: PROCESS LOCKING 
  

  Prints a timed trace of semop(2)/semtimedop(2) syscalls

  # stap semop-watch.stp -c 'sleep 2'

• ¶ process/sig_by_pid.stp - Signal Counts by Process ID
  keywords: SIGNALS 
  

  Print signal counts by process ID in descending order.

  # stap sig_by_pid.stp -c "sleep 1"

• ¶ process/sig_by_proc.stp - Signal Counts by Process Name
  keywords: SIGNALS 
  

  Print signal counts by process name in descending order.

  # stap sig_by_proc.stp -c "sleep 1"

• ¶ process/sigkill.stp - Track SIGKILL Signals
  keywords: SIGNALS 
  

  The script traces any SIGKILL signals. When that SIGKILL signal is sent to a process, the script prints out the signal name, the destination executable and process ID, the executable name and user ID that sents the signal.

  # stap sigkill.stp -c "sleep 1"

• ¶ process/sigmon.stp - Track a Particular Signal to a Specific Process
  keywords: SIGNALS 
  

  The script watches for a particular signal sent to a specific process. When that signal is sent to the specified process, the script prints out the PID and executable of the process sending the signal, the PID and executable name of the process receiving the signal, and the signal number and name.

  # stap sigmon.stp -c "sleep 1" SIGKILL

• ¶ process/sleepingBeauties.stp - Generate Backtraces of Threads Waiting for IO Operations
  keywords: IO SCHEDULER BACKTRACE 
  

  The script monitors the time that threads spend in waiting for IO operations (in "D" state) in the wait_for_completion function. If a thread spends over 10ms, its name and backtrace is printed, and later so is the total delay.

  # stap sleepingBeauties.stp -c "sleep 1"

• ¶ process/sleeptime.stp - Trace Time Spent in Nanosleep Syscalls
  keywords: SYSCALL NANOSLEEP 
  

  The script watches each nanosleep syscall on the system. At the end of each nanosleep syscall the script prints out a line with a timestamp in microseconds, the pid, the executable name in parentheses, the "nanosleep:" key, and the duration of the sleep in microseconds.

  # stap sleeptime.stp -c "sleep 1"

• ¶ process/strace.stp - Trace system calls
  keywords: PROCESS SYSCALL 
  

  The script loosely emulates strace, when applied to individual processes or hierarchies (via -c/-x), or the entire system (without -c/-x). A few output configuration parameters may be set with -G.

  # stap strace.stp -c "sleep 1"

• ¶ process/syscalls_by_pid.stp - System-Wide Count of Syscalls by PID
  keywords: SYSCALL 
  

  The script watches all syscall on the system. On exit the script prints a list showing the number of systemcalls executed by each PID ordered from greatest to least number of syscalls.

  # stap syscalls_by_pid.stp -c "sleep 1"

• ¶ process/syscalls_by_proc.stp - System-Wide Count of Syscalls by Executable
  keywords: SYSCALL 
  

  The script watches all syscall on the system. On exit the script prints a list showing the number of systemcalls executed by each executable ordered from greatest to least number of syscalls.

  # stap syscalls_by_proc.stp -c "sleep 1"

• ¶ process/syscalltimes - System-Wide Syscall Statistics with Filtering
  keywords: SYSCALL 
  

  Combination shell/systemtap script to measure system call counts and times. Can be filtered by process IDs, process names and users.

  # ./syscalltimes -c 'sleep 1'

• ¶ process/thread-business.stp - monitor syscall history
  keywords: PROCESS SYSCALL 
  

  Prints a periodic tabular report about the counts of syscall activity of all threads on the system, along with a textual recent-syscall-history for each

  # stap thread-business.stp -c "sleep 10"

• ¶ process/threadstacks.stp - Override default new-pthread stack sizes
  keywords: THREAD GURU 
  

  Overrides default NPTL pthread_create stack size for all new threads created by target processes. Reports one line per process when the related glibc variable __default_stacksize is updated. Moot for glibc versions that support $LIBC_PTHREAD_DEFAULT_STACKSIZE_NP.

  # stap -g threadstacks.stp -Gsize=65536 -c "sleep 1" -d `which stap`

• ¶ process/wait4time.stp - Trace Time Spent in wait4 Syscalls
  keywords: SYSCALL PROCESS 
  

  The script watches each wait4 syscall on the system. At the end of each wait4 syscall the script prints out a line with a timestamp in microseconds, the pid, the executable name in parentheses, the "wait4:" key, the duration of the wait and the PID that the wait4 was waiting for. If the waited for PID is not specified , it is "-1".

  # stap wait4time.stp -c "sleep 1"

• ¶ profiling/errno.stp - Show Which Processes and System Calls Return Errors Most Frequently
  keywords: PROFILING 
  

  On exit the errno.stp script provides a sorted list showing which combination of PID, system call, and error occur most frequently.

  # stap errno.stp -c "sleep 1"

• ¶ profiling/fntimes.stp - Show Functions Taking Longer Than Usual
  keywords: PROFILING 
  

  The fntimes.stp script monitors the execution time history of a given function family (assumed non-recursive). Each time (beyond a warmup interval) is then compared to the historical maximum. If it exceeds a certain threshold (250%), a message is printed.

  # stap fntimes.stp 'kernel.function("sys_*")' -c "sleep 7"

• ¶ profiling/functioncallcount.stp - Count Times Functions Are Called
  keywords: PROFILING FUNCTION 
  

  The functioncallcount.stp script takes one argument, a list of functions to probe. The script will run and count the number of times that each of the functions on the list is called. On exit the script will print a sorted list from most frequently to least frequently called function.

  # stap -w functioncallcount.stp "*@mm/*.c" -c "sleep 1"

• ¶ profiling/latencytap.stp - Show Reasons and Durations for Processes Sleeping
  keywords: PROFILING 
  

  The latencytap.stp script collects data on the intervals processes are deactivated (sleeping). The script categorizes the reasons for the sleeps by analyzing the backtraces and displays a sorted list of the top 20 causes from largest total sum time sleeping to smallest. The output is updated every 30 seconds. The script needs to be compiled with the '--all-modules' option to produce reasons for sleeps caused by modules. Optionally, this script can be used with the '-c' or '-x' options to focus on a specific PID.

  # stap latencytap.stp --all-modules -c "sleep 1"

• ¶ profiling/linetimes.stp - Show Time Spent on Each Line of a Function
  keywords: PROFILING 
  

  The linetimes.stp script takes two arguments: where to find the function and the function name. linetimes.stp will instrument each line in the function. It will print out the number of times that the function is called, a table with the average and maximum time each line takes, and control flow information when the script exits.

  # stap linetimes.stp kernel sys_nanosleep -c "sleep 1"

• ¶ profiling/perf.stp - Show performance ratios using perf.counter to access performance counters
  keywords: PROFILING 
  

  On exit the perf.stp script provides a sorted list showing cycles per insn, branches per insn, and cache refs per insn

  # stap perf.stp -c "find /usr/bin -name \"l*\" -printf \"%h/%f %s %Cx \%Ck%CM %Y\n\""

• ¶ profiling/periodic.stp - Show the Period of the Various Timers on the System
  keywords: PROFILING 
  

  The periodic.stp script uses the kernel.trace("timer_expire_entry") tracepoint to collect data on period and frequency of the various timers on the system. The script displays a sorted list of the timers observed on the system from most frequent to least frequent. The script needs to be compiled with the '--all-modules' option to produce list the function names. Optionally, this script can be used with a numerical argument to indicate the interval in seconds between printing output.

  # stap periodic.stp --all-modules -c "sleep 1"

• ¶ profiling/pf2.stp - Profile Kernel Functions
  keywords: PROFILING 
  

  The pf2.stp script sets up time-based sampling. Every five seconds it prints out a sorted list with the top ten kernel functions with samples.

  # stap pf2.stp -c "sleep 1"

• ¶ profiling/pf3.stp - Profile Kernel/User Functions
  keywords: PROFILING 
  

  The pf3.stp script sets up time-based sampling. Every five seconds it prints out a sorted list with the top twenty kernel and/or user functions with samples. Use any of --ldd, --all-modules, -d MODULE, -d /PATH/TO/EXEC to add more symbolic info.

  # stap pf3.stp -c "sleep 6" --all-modules --ldd

• ¶ profiling/pf4.stp - Profile Kernel/User Backtraces
  keywords: PROFILING 
  

  The pf4.stp script sets up time-based sampling. Every five seconds it prints out a sorted list with the top twenty kernel and/or user stack backtraces (on a per-cpu basis). Use any of --ldd, --all-modules, -d MODULE, -d /PATH/TO/EXEC to add more symbolic info.

  # stap pf4.stp -c "sleep 6" --all-modules --ldd

• ¶ profiling/sched_switch.stp - Display the Task Switches Happening in the Scheduler
  keywords: PROFILING FUNCTION 
  

  The sched_switch.stp script takes two arguments, first argument can be "pid" or "name" to indicate what is being passed as second argument. The script will trace the process based on pid/name and print the scheduler switches happening with the process. If no arguments are passed, it displays all the scheduler switches. This can be used to understand which tasks schedule out the current process being traced, and when it gets scheduled in again.

  # stap  sched_switch.stp -c "sleep 1"

• ¶ profiling/thread-times.stp - Profile Kernel Functions
  keywords: PROFILING 
  

  The thread-times.stp script sets up time-based sampling. Every five seconds it prints out a sorted list with the top twenty threads occupying the CPUs, broken down as a percentage of user and kernel time.

  # stap thread-times.stp -c "sleep 1"

• ¶ profiling/timeout.stp - Show Processes Doing Polling Operations
  keywords: PROFILING 
  

  The timeout.stp script is based on a blog entry (http://udrepper.livejournal.com/19041.html) mentioning a need for a tool to help developers find applications that are polling. The timeout.stp script monitors systemcall used for polling and records the systemcalls that timed out rather than returned because some action occurred. The script updates the screen once a second with the top twenty processes.

  # stap timeout.stp -c "sleep 1"

• ¶ profiling/topsys.stp - Show Processes Doing Polling Operations
  keywords: PROFILING 
  

  The topsys.stp script lists out the top twenty systemcalls for the previous 5 seconds. The output is sorted from most frequent to least frequent.

  # stap topsys.stp -c "sleep 1"

• ¶ stapgames/2048.stp - 2048
  keywords: STAPGAMES 
  

  The modern classic 2048 sliding-tiles game, using local keyboard and ansi animation.

  # stap -p4 2048.stp

• ¶ stapgames/block.stp - block breaker game
  keywords: STAPGAMES 
  

  A block game where you progressively break the ceiling blocks until clearing the level

  # stap -p4 -Itapset/ block.stp

• ¶ stapgames/eater.stp - eater game
  keywords: STAPGAMES 
  

  walk through a maze, eat stuff

  # stap -p4 -Itapset/ eater.stp

• ¶ stapgames/lifegame.stp - life game
  keywords: STAPGAMES 
  

  watch as your creation morphes into different forms

  # stap -p4 -Itapset/ lifegame.stp

• ¶ stapgames/pingpong.stp - pingpong game
  keywords: STAPGAMES 
  

  A simulated ball bounces around the terminal reflecting at the edges

  # stap -p4 -Itapset/ pingpong.stp

• ¶ virtualization/kvm_service_time.stp - Time Statistics on KVM Exit Reasons
  keywords: VIRTUALIZATION KVM 
  

  The kvm_service_time.stp script tracks the statistics about the amount of time that the processor left the guest virtual machine for each exit reason (for example fixing up a page table or handling an IO operation). When the script exits it prints out the number of times each exit reason was encountered, the total duration of time it left the guest VM, the minimum time, the average time, and the maximum time in microseconds for that exit reason. On Linux 2.6.38 and newer kernel the script can automatically determine whether it is running on Intel or AMD processors. For older kernels with a kernel.trace("kvm_exit") tracepoint that does not have the $isa parameter you can explicitly state the kvm type with a "-G kvm=intel" or "-G kvm=amd" on the command line.

  # stap kvm_service_time.stp -c "sleep 1"

• ¶ virtualization/qemu_count.stp - Tally the Number of User-Space QEMU Events
  keywords: VIRTUALIZATION QEMU KVM 
  

  The qemu_count.stp script tallies the number of times each of the user-space qemu probepoints is encountered. When the script exits, it prints a list of the number of times each user-space qemu probepoint is encountered.

  # stap qemu_count.stp -c "sleep 1"

• ¶ virtualization/qemu_io.stp - Tally the Number of User-Space QEMU IO on Each IO Port
  keywords: VIRTUALIZATION QEMU KVM IO 
  

  The qemu_io.stp script tallies the number of times each of the IO port on the guest virtual machines is touched by a input or output operation. When the script exits, it prints a count of the number of times each IO port read and written.

  # stap qemu_io.stp -c "sleep 1"

Example Indexes

• All Examples
• By Keyword

All 124 Examples

• ¶ general/alias_suffixes.stp - Count I/O Syscalls using Alias Suffixes
  keywords: IO STATISTICS 
  

  alias_suffixes.stp is a demonstration of how alias suffixes in the systemtap language might be used. The script tracks the wall clock time for each invocation of the system calls open, close, read, and write. When the script exists it prints out the minimum, average, and maximum times in microseconds for each system call, followed by a count of times that each syscall was invoked and a histogram showing the distributions of times.

  # stap alias_suffixes.stp -c "sleep 1"

• ¶ general/ansi_colors.stp - Color Table for ansi_set_color2() and ansi_set_color3()
  keywords: FORMAT 
  

  The script prints a table showing the available color combinations for the ansi_set_color2() and ans_set_color3() functions in the ansi.stp tapset.

  # stap ansi_colors.stp

• ¶ general/ansi_colors2.stp - Show Attribues in Table for ansi_set_color3()
  keywords: FORMAT 
  

  The script prints a table showing the available attributes (bold, underline, and inverse) with color combinations for the ans_set_color3() function in the ansi.stp tapset.

  # stap ansi_colors2.stp

• ¶ general/badname.stp - Bad Filename Filter
  keywords: FILESYSTEM GURU 
  

  The badname.stp script shows how one could prevent the creation of files with undesirable names using guru mode.

  # stap -g badname.stp -c "touch /tmp/myXXXbadnameXXXfile.$$ 2>&1 | grep \denied"

• ¶ general/eventcount.stp - Count Specified Events
  keywords: STATISTICS THREAD PROCESS 
  

  The script periodically prints a count of specified events and their related tid's over the course of execution. Numerous configuration options exist to control filtering / reporting, see the script source.

  # stap eventcount.stp syscall.* -c 'sleep 1'

• ¶ general/func_time_stats.stp - Function Time Statistics
  keywords: FUNCTION STATISTICS 
  

  The func_time_stats.stp script tracks the wall clock time for each invocation of the function probe listed as the first command line argument. When the script exits it prints out the minimum, average, and maximum times in microseconds followed by a count of times that the function was called and a histogram showing the distributions of times.

  # stap func_time_stats.stp 'syscall.nanosleep' -c "sleep 1"

• ¶ general/graphs.stp - Graphing Disk and CPU Utilization
  keywords: DISK CPU UTILIZATION 
  

  The script tracks the disk and CPU utilization. The resulting output of the script can be piped into gnuplot to generate a graph of disk and CPU USE.

  # stap graphs.stp -c "sleep 1"

• ¶ general/helloworld.stp - SystemTap "Hello World" Program
  keywords: SIMPLE 
  

  A basic "Hello World" program implemented in SystemTap script. It prints out "hello world" message and then immediately exits.

  # stap helloworld.stp

• ¶ general/para-callgraph-verbose.stp - Callgraph Tracing with Verbose Arguments
  keywords: TRACE CALLGRAPH 
  

  Print a timed per-thread microsecond-timed callgraph, complete with pretty-printed function parameters and return values. The first parameter names the function probe points to trace. The optional second parameter names the probe points for trigger functions, which acts to enable tracing for only those functions that occur while the current thread is nested within the trigger.

  # stap para-callgraph-verbose.stp 'kernel.function("*@fs/proc*.c")' \'kernel.function("vfs_read")' -c "cat /proc/sys/vm/* || true"

• ¶ general/para-callgraph.stp - Callgraph Tracing with Arguments
  keywords: TRACE CALLGRAPH 
  

  Print a timed per-thread microsecond-timed callgraph, complete with function parameters and return values. The first parameter names the function probe points to trace. The optional second parameter names the probe points for trigger functions, which acts to enable tracing for only those functions that occur while the current thread is nested within the trigger.

  # stap para-callgraph.stp 'kernel.function("*@fs/proc*.c")' \'kernel.function("vfs_read")' -c "cat /proc/sys/vm/* || true"

• ¶ general/py2example.stp - SystemTap python 2 support tapset
  keywords: SIMPLE 
  

  A python support tapset that displays backtraces and variable values

  # stap -I tapset -c '/usr/bin/python2 pyexample.py 35' py2example.stp

• ¶ general/py3example.stp - SystemTap python 3 support tapset
  keywords: SIMPLE 
  

  A python support tapset that displays backtraces and variable values

  # stap -g --suppress-time-limits -I tapset -c '/usr/bin/python3 \pyexample.py 35' py3example.stp

• ¶ general/regex.stp - Report opened files whose names match a given regex
  keywords: REGEX 
  

  Uses the regex functionality to detect opened files whose names match a pattern given on the command line. If no command line parameter is given, demonstrate by filtering for files that end with an extension showing them to be an archive.

  # stap regex.stp -c "sleep 1"

• ¶ general/sizeof.stp - Print the Size of a C Type
  keywords: STATISTICS MEMORY 
  

  This script prints the size of a type, based on dwarf debuginfo for any kernel or userspace module, or trial-compilation of a given header file name.

  # stap sizeof.stp FILE '</usr/include/stdio.h>'

• ¶ general/stopwatches.stp - See the amount of wall clock time a process spends in various states
  keywords: TIME 
  

  The stopwatch.stp script illustrates how to use multiple stopwatches record how much wallclock time a process spends in kernel- and user-space. On exit the script prints out the time in seconds, milliseconds, microseconds, and nanoseconds. Note that this output of this script is not directly comparable to the time command because time records the time that the process is actually active in kernel- and user-space.

  # stap stopwatches.stp -c "sleep 1"

• ¶ general/varwatch.stp - Watch a Variable Changing Value in a Thread
  keywords: MONITORING 
  

  This script places a set of probes (specified by $1), each of which monitors the state of some context $variable expression (specified by $2). Whenever the value changes, with respect to the active thread, the event is traced.

  # stap -w varwatch.stp 'kernel.statement("do_sys_open@fs/open.c:*")' \'$$vars' -c "sleep 1"

• ¶ general/watchdog.stp - Watchdog Timer for Arbitrary Events
  keywords: WATCHDOG BACKTRACE 
  

  The watchdog.stp script provides a watchdog timer mechanism for arbitrary events. The script takes three arguments: the events to start watchdog timer, the event to stop the watchdog timer, and the time in millseconds for the watchdog. If the watchdog timer is exceed, the script will trigger a stack backtrace of the user-process that timed out using pstack. This script can be used to diagnose what the userspace application is doing when a slower than expected operation occurs.

  # stap watchdog.stp 'syscall.nanosleep' 'syscall.nanosleep.return' 1000 \-c "sleep 1"

• ¶ interrupt/interrupts-by-dev.stp - Record Interrupts on a Per-Device Basis
  keywords: INTERRUPT 
  

  The interrupts-by-dev.stp script profiles interrupts received by each device per 100 ms.

  # stap interrupts-by-dev.stp -c "sleep 1"

• ¶ interrupt/scf.stp - Tally Backtraces for Inter-Processor Interrupt
  keywords: INTERRUPT BACKTRACE 
  

  The Linux kernel function smp_call_function causes expensive inter-processor interrupts (IPIs). The scf.stp script tallies the processes and backtraces causing the interprocessor interrupts to identify the cause of the expensive IPI. On exit the script prints the tallies in descending frequency.

  # stap scf.stp -c "sleep 1"

• ¶ io/deviceseeks.stp - Histograms of Seek Behavior for Each Device
  keywords: DISK 
  

  The deviceseeks.stp script generates a histogram showing the frequency of different sized seeks (in sectors) on each device.

  # stap deviceseeks.stp -c "sleep 1"

• ¶ io/disktop.stp - Summarize Disk Read/Write Traffic
  keywords: DISK 
  

  Get the status of reading/writing disk every 5 seconds, output top ten entries during that period.

  # stap disktop.stp -c "sleep 1"

• ¶ io/eatmydata.stp - disable fsync
  keywords: IO GURU SIMPLE 
  

  Suppresses fsync() syscalls from processes identified by stap -c/-x by turning them into presumed-faster fsync() on file descriptor 1 (stdout).

  # stap -g eatmydata.stp -c 'strace ls || true'

• ¶ io/enospc.stp - Report an disk out-of-space condition.
  keywords: DISK FILESYSTEM 
  

  This script monitors a filesystem implementations for early internal indications of ENOSPC, and reports these to the system logger and the systemtap console.

  # stap enospc.stp -c "sleep 1"

• ¶ io/inodewatch.stp - Monitoring Reads and Writes to a File
  keywords: IO 
  

  The inodewatch.stp outputs the executable name and process id each time a read or write occurs to the specified inode on the specified major/minor device.

  # stap inodewatch.stp 0x08 0x01 100 -c "sleep 1"

• ¶ io/inodewatch2.stp - Monitoring Attribute Changes to a File
  keywords: IO 
  

  The inodewatch2.stp script outputs the executable name, process id, and attributes each time the attributes are changed on the specified inode on the specified major/minor device.

  # stap inodewatch2.stp 0x08 0x01 100 -c "sleep 1"

• ¶ io/io_submit.stp - Tally Reschedule Reason During AIO io_submit Call
  keywords: IO BACKTRACE 
  

  When a reschedule occurs during an AIO io_submit call, accumulate the traceback in a histogram. When the script exits prints out a sorted list from most common to least common backtrace.

  # stap io_submit.stp -c "sleep 1"

• ¶ io/ioblktime.stp - Average Time Block IO Requests Spend in Queue 
  keywords: IO 
  

  The ioblktime.stp script tracks the amount of time that each block IO requests spend waiting for completion. The script computes the average waiting time for block IO per device and prints list every 10 seconds. In some cases there can be too many outstanding block IO operations and the script may exceed the default number of MAXMAPENTRIES allowed. In this case the allowed number can be increased with "-DMAXMAPENTRIES=10000" option on the stap command line.

  # stap ioblktime.stp -c "sleep 1"

• ¶ io/iodevstats.stp - List Executables Reading and Writing the Most Data by Device
  keywords: IO PROFILING 
  

  The iodevstats.stp script measures the amount of data successfully read and written by all the executables for each io device on the system. The output is sorted from greatest sum of bytes read and written to a device by an executable to the least. The output contains device major/minor number, the count of operations (reads and writes), the totals and averages for the number of bytes read and written.

  # stap iodevstats.stp -c "sleep 1"

• ¶ io/iostat-scsi.stp - IO Statistics for SCSI Devices
  keywords: IO PROFILING SCSI 
  

  The iostat-scsi.stp script provides a breakdown of the number of blks read and written on the machine's various SCSI devices. The script takes one argument which is the number of seconds between reports.

  # stap -g iostat-scsi.stp 1 -c "sleep 1"

• ¶ io/iostats.stp - List Executables Reading and Writing the Most Data
  keywords: IO PROFILING 
  

  The iostat.stp script measures the amount of data successfully read and written by all the executables on the system. The output is sorted from most greatest sum of bytes read and written by an executable to the least. The output contains the count of operations (opens, reads, and writes), the totals and averages for the number of bytes read and written.

  # stap iostats.stp -c "sleep 1"

• ¶ io/iotime.stp - Trace Time Spent in Read and Write for Files 
  keywords: PROFILING SYSCALL IO FILE 
  

  The script watches each open, close, read, and write syscalls on the system. For each file the scripts observes opened it accumulates the amount of wall clock time spent in read and write operations and the number of bytes read and written. When a file is closed the script prints out a pair of lines for the file. Both lines begin with a timestamp in microseconds, the PID number, and the executable name in parentheses. The first line with the "access" keyword lists the file name, the attempted number of bytes for the read and write operations. The second line with the "iotime" keyword list the file name and the number of microseconds accumulated in the read and write syscalls.

  # stap iotime.stp -c "sleep 1"

• ¶ io/iotop.stp - Periodically Print IO Activity by Process Name
  keywords: IO 
  

  Every five seconds print out the top ten executables generating I/O traffic during that interval sorted in descending order.

  # stap iotop.stp -c "sleep 1"

• ¶ io/mbrwatch.stp - Monitor Read/Write of the Boot Sector Area of Block Devices
  keywords: IO MONITORING DISK 
  

  The mbrwatch.stp script reports any attempted reads/writes of the first few sectors of a raw block device.

  # stap mbrwatch.stp -c "dd of=/dev/null count=1 if=/dev/`grep -v major \/proc/partitions | grep . | awk '{print $4}' | head -1`"

• ¶ io/nfs_func_users.stp - Tally the Number of NFS Functions Used by Each Process
  keywords: IO PROFILING 
  

  The nfs_func_users.stp script counts the uses of NFS functions in the kernel on a per process bases. The output is sorted from the process with the greatest number of NFS functions called to the least. The output contains the executable name, the process number, and the total number of NFS functions called by the process.

  # stap nfs_func_users.stp -c "sleep 1"

• ¶ io/traceio.stp - Track Cumulative IO Activity by Process Name
  keywords: IO 
  

  Every second print out the top ten executables sorted in descending order based on cumulative I/O traffic observed.

  # stap traceio.stp -c "sleep 1"

• ¶ io/traceio2.stp - Watch IO Activity on a Particular Device
  keywords: IO 
  

  Print out the executable name and process number as reads and writes to the specified device occur.

  # stap traceio2.stp 0x0801 -c "sleep 1"

• ¶ io/ttyspy.stp - Monitor TTY Typing
  keywords: IO TTY MONITORING GURU 
  

  The ttyspy.stp script uses tty_audit hooks to monitor recent typing activity on the system, printing a scrolling record of recent keystrokes, on a per-tty basis.

  # stap --skip-badvars -g ttyspy.stp -c "sleep 1"

• ¶ locks/bkl.stp - Tracing Contention on Big Kernel Lock
  keywords: LOCKING 
  

  The bkl.stp script can help determine whether the Big Kernel Lock (BKL) is causing serialization on a multiprocessor system due to excessive contention of the BKL. The bkl.stp script takes one argument which is the number of processes waiting for the Big Kernel Lock (BKL). When the number of processes waiting for the BKL is reached or exceeded, the script will print a time stamp, the number of processes waiting for the BKL, the holder of the BKL, and the amount of time the BKL was held.

  # stap bkl.stp -c "sleep 1" 1

• ¶ locks/bkl_stats.stp - Per Process Statistics on Big Kernel Lock Use
  keywords: LOCKING 
  

  The bkl_stats.stp script can indicate which processes have excessive waits for the Big Kernel Lock (BKL) and which processes are taking the BKL for long periods of time. The bkl_stats.stp script prints lists of all the processes that require the BKL. Every five seconds two tables are printed out. The first table lists the processes that waited for the BKL followed by the number of times that the process waited, the minimum time of the wait, the average and the maximum time waited. The second table lists has similar information for the time spent in holding the lock for each of the processes.

  # stap bkl_stats.stp -c "sleep 1"

• ¶ memory/hw_watch_addr.stp - Watch a Kernel Address Using Breakpoint Hardware
  keywords: MEMORY WATCHPOINT 
  

  The script will watch accesses to a single kernel address and prints a traceback each time the address is accessed. This script needs to be run as root to allow access to the breakpoint hardware.

  # stap --all-modules hw_watch_addr.stp 0x`grep "vm_dirty_ratio" \/proc/kallsyms` -c "sleep 5"

• ¶ memory/hw_watch_sym.stp - Watch a Kernel Symbol Using Breakpoint Hardware
  keywords: MEMORY WATCHPOINT 
  

  The script will watch accesses to the starting address of a single kernel symbol and prints a traceback each time the symbol is accessed. This script needs to be run as root to allow access to the breakpoint hardware.

  # stap --all-modules hw_watch_sym.stp vm_dirty_ratio -c "sleep 5"

• ¶ memory/kmalloc-top - Show Paths to Kernel Malloc Invocations
  keywords: MEMORY 
  

  The kmalloc-top perl program runs a small systemtap script to collect stack traces for each call to the kmalloc function and counts the time that each stack trace is observed. When kmalloc-top exits it prints out sorted list. The output can be filtered to print only the first N stack traces (-t), stack traces with a minimum counts (-m), or exclude certain stack traces (-e).

  # ./kmalloc-top -c "sleep 1"

• ¶ memory/last_100_frees.stp - Log recent free(3) calls.
  keywords: MEMORY PROCESS BACKTRACE 
  

  This script reports on the last few free(3) libc calls done by processes (possibly restricted by stap -x/-c), along with a userspace backtrace at those moments.

  # stap last_100_frees.stp -c "stap -V" -d `which stap` --ldd

• ¶ memory/mmanonpage.stp - Track Virtual Memory System Actions on Anonymous Pages
  keywords: MEMORY 
  

  The mmanonpage.stp script uses the virtual memory tracepoints available in some kernels to track the number of faults, user space frees, page ins, copy on writes and unmaps for anonymous pages. When the script is terminated the counts are printed for each process that allocated pages while the script was running. This script displays the anonymous page statistics for each process that ran while the script is active. It's useful in debugging leaks in the anonymous regions of a process.

  # stap mmanonpage.stp -c "sleep 1"

• ¶ memory/mmfilepage.stp - Track Virtual Memory System Actions on File Backed Pages
  keywords: MEMORY 
  

  The mmfilepage.stp script uses the virtual memory tracepoints available in some kernels to track the number of faults, copy on writes mapping, and unmapping operations for file backed pages. When the script is terminated the counts are printed for each process that allocated pages while the script was running. The mmfilepage.stp script is useful in debugging leaks in the mapped file regions of a process.

  # stap mmfilepage.stp -c "sleep 1"

• ¶ memory/mmreclaim.stp - Track Virtual Memory System Page Reclamation
  keywords: MEMORY 
  

  The mmreclaim.stp script uses the virtual memory tracepoints available in some kernels to track page reclaim activity that occurred while the script was running. It's useful in debugging performance problems that occur due to page reclamation.

  # stap mmreclaim.stp -c "sleep 1"

• ¶ memory/mmwriteback.stp - Track Virtual Memory System Writing to Disk
  keywords: MEMORY 
  

  The mmwriteback.stp script uses the virtual memory tracepoints available in some kernels to report all of the file writebacks that occur form kupdate, pdflush and kjournald while the script is running. It's useful in determining where writes are coming from on a supposedly idle system that is experiencing unexpected IO.

  # stap mmwriteback.stp -c "sleep 1"

• ¶ memory/numa_faults.stp - Summarize Process Misses across NUMA Nodes
  keywords: MEMORY NUMA 
  

  The numa_faults.stp script tracks the read and write pages faults for each process. When the script exits it prints out the total read and write pages faults for each process. The script also provide a break down of page faults per node for each process. This script is useful for determining whether the program has good locality (page faults limited to a single node) on a NUMA computer.

  # stap numa_faults.stp -c "sleep 1"

• ¶ memory/overcommit.stp - Log Failed Process Memory Allocation Due to Overcommit Limits
  keywords: MEMORY LIMITS 
  

  The overcommit.stp script prints a line each time the kernel refuses a memory allocation request from a process because of /proc/sys/vm/overcommit* limits.

  # stap overcommit.stp -c "sleep 1"

• ¶ memory/pfaults.stp - Generate Log of Major and Minor Page Faults
  keywords: MEMORY 
  

  The pfaults.stp script generates a simple log for each major and minor page fault that occurs on the system. Each line contains a timestamp (in microseconds) when the page fault servicing was completed, the pid of the process, the address of the page fault, the type of access (read or write), the type of fault (major or minor), and the elapsed time for page fault. This log can be examined to determine where the page faults are occurring.

  # stap pfaults.stp -c "sleep 1"

• ¶ memory/vm.tracepoints.stp - Collect Slab Allocation Statistics
  keywords: MEMORY SLAB STATISTICS 
  

  The script will probe all memory slab/slub allocations and collects information about the size of the object (bytes requested) and user-space process in execution. When run over a period of time, it helps to correlate kernel-space memory consumption owing to user-space processes.

  # stap vm.tracepoints.stp -c "sleep 10"

• ¶ network/autofs4.stp - Watch autofs4 Operations
  keywords: NETWORK AUTOFS NFS 
  

  Trace key autofs4 operations such as mounting or unmounting remote filesystems.

  # stap autofs4.stp -c "sleep 1"

• ¶ network/connect_stat.stp - Show Process Ancestry for IP Connections
  keywords: NETWORK SOCKET PROCESS 
  

  The connect_stat.stp script prints a task's entire ancestry (parent process name/uid/gid) whenever it attempts an outgoing socket connection to a given IP address.

  # stap connect_stat.stp 127.0.0.1 -c "sleep 1"

• ¶ network/dropwatch.stp - Watch Where Socket Buffers Are Freed in the Kernel
  keywords: NETWORK TRACEPOINT SOCKET 
  

  Every five seconds the dropwatch.stp script lists the number of socket buffers freed at locations in the kernel.

  # stap dropwatch.stp -c "sleep 1"

• ¶ network/netdev.stp - Trace Activity on Network Devices
  keywords: NETWORK DEVICE TRAFFIC 
  

  The netdev.stp script traces configuration and transmit/receive activity on network devices.

  # stap netdev.stp -c "sleep 1"

• ¶ network/netfilter_drop.stp - System-Wide Network Packet Dropping Tool
  keywords: NETWORK PACKETS GURU 
  

  The script drops the specified number of packets of the specified protocol. Valid protocols are TCP, UDP, or ALL. If ALL is specified, all incoming packets are dropped. The number of packets to drop can be specified with a positive integer. A value of 0 indicates that packets should be dropped until the user manually exits.

  # stap -g netfilter_drop.stp TCP 1 -c "sleep 2"

• ¶ network/netfilter_summary.stp - System-Wide Count of Network Packets by IPs
  keywords: NETWORK TRAFFIC 
  

  The script watches all IPv4 network traffic on the system. On exit the script prints a list showing the number of packets sent along source IP address / destination IP address pair encountered, and the total number of bytes sent among the pair. The list is ordered from greatest to least number of packets seen among the source/destination pairs.

  # stap netfilter_summary.stp -c "sleep 1"

• ¶ network/nettop.stp - Periodic Listing of Processes Using Network Interfaces
  keywords: NETWORK TRAFFIC 
  

  Every five seconds the nettop.stp script prints out a list of processed (PID and command) with the number of packets sent/received and the amount of data sent/received by the process during that interval.

  # stap nettop.stp -c "sleep 1"

• ¶ network/nfsd-recent.stp - Keep track of NFS server statistics
  keywords: NFS STATISTICS 
  

  This script tracks all nfsd server operations by client_ip address, and periodically lists those clients that have made recent requests. It's a way of finding out which nfs clients might be considered still connected.

  # stap nfsd-recent.stp -c "sleep 1"

• ¶ network/nfsd_unlink.stp - Find Which Client Is Removing NFS Files on Server
  keywords: NFS DISK 
  

  The nfsd_unlink.stp script lists the ip address and file name each time time a file is being removed or unlinked by the nfsd. This script is run on the nfs server.

  # stap nfsd_unlink.stp -c "sleep 1"

• ¶ network/nfsdtop.stp - Keep track of NFS server statistics
  keywords: NFS STATISTICS 
  

  The nfsdtop.stp script gathers and displays NFS lookups,

  # stap nfsd_unlink.stp -c "sleep 1"

• ¶ network/sk_stream_wait_memory.stp - Track Start and Stop of Processes Due to Network Buffer Space
  keywords: NETWORK TCP PROCESS 
  

  The sk_stream-wait_memory.stp prints a time stamp, executable, and pid each time a process blocks due to the send buffer being full. A similar entry is printed each time a process continues because there is room in the buffer.

  # stap sk_stream_wait_memory.stp -c "sleep 1"

• ¶ network/socket-trace.stp - Trace Functions Called in Network Socket Code
  keywords: NETWORK SOCKET 
  

  The script instruments each of the functions in the Linux kernel's net/socket.c file. The script prints out trace data. The first element of a line is time delta in microseconds from the previous entry. This is followed by the command name and the PID. The "->" and "<-" indicates function entry and function exit, respectively. The last element of the line is the function name.

  # stap socket-trace.stp -c "sleep 1"

• ¶ network/socktop - Periodically Summarize Socket Activity on the System
  keywords: NETWORK SOCKET 
  

  The socktop script periodically prints out a list of the processes with the highest socket activity. Command line options for the script allow filtering to focus on particular types of sockets. The "-h" option lists socktop script's filtering options.

  # ./socktop -c 1

• ¶ network/tcp_connections.stp - Track Creation of Incoming TCP Connections
  keywords: NETWORK TCP SOCKET 
  

  The tcp_connections.stp script prints information for each new incoming TCP connection accepted by the computer. The information includes the UID, the command accepting the connection, the PID of the command, the port the connection is on, and the IP address of the originator of the request.

  # stap tcp_connections.stp -c "sleep 1"

• ¶ network/tcp_init_cwnd.stp - Increase Initial TCP Congestion Window to 10
  keywords: NETWORK TCP SOCKET GURU 
  

  Run the tcp_init_cwnd.stp script in the background to override a kernel's default tcp cwnd value to 10, which has been found to improve latency for web server type workloads. The script prints a count of cwnd value changes when it is stopped.

  # stap -g tcp_init_cwnd.stp -c "sleep 1"

• ¶ network/tcp_trace.stp - TCP Connection Tracing Utility
  keywords: NETWORK TRACE 
  

  This scripts traces a given TCP connection based on the filter parameters given by the user. The indexing is done by the 4 tuples local address, remote address, local port, remote port.

  # stap tcp_trace.stp 127.0.0.1:*-127.0.0.1:* timeout=1

• ¶ network/tcpdumplike.stp - Dump of Received UDP/TCP Packets
  keywords: NETWORK TRAFFIC 
  

  The tcpdumplike.stp prints out a line for each TCP & UDP packet received. Each line includes the source and destination IP addresses, the source and destination ports, and flags.

  # stap tcpdumplike.stp -c "sleep 1"

• ¶ network/tcpipstat.stp - Display Network Statistics for Individual TCP Sockets
  keywords: NETWORK STATISTICS 
  

  The tcpipstat script collects and displays network statistics related to individual TCP sockets or groups of sockets. The statistics that are collected are simular to that of the command netstat -s, only sorted and grouped by individual sockets.

  # stap tcpipstat.stp timeout=1

• ¶ process/auditbt.stp - Generate backtraces for kernel audit events
  keywords: MONITORING SECURITY AUDIT BACKTRACE 
  

  Attaches to the kernel audit-log paths (also used by libaudit), and log every record being sent, along with a user-space backtrace of the process that caused it.

  # stap auditbt.stp -d /usr/bin/sudo --ldd -c "sudo true"

• ¶ process/chng_cpu.stp - Monitor Changes in Processor Executing a Task
  keywords: SCHEDULER 
  

  The chng_cpu.stp script takes an argument which is the executable name of the task it should monitor. Each time a task with that executable name is found running on a different processor, the script prints out the thread id (tid), the executable name, the processor now running the task, the thread state, and a backtrace showing the kernel functions that triggered the running of the task on the processor.

  # stap chng_cpu.stp -c "sleep 1" bash

• ¶ process/cycle_thief.stp - Track IRQ's and Other Processes Stealing Cycles from a Task
  keywords: PROCESS SCHEDULER TIME TRACEPOINT INTERRUPT 
  

  The cycle_thief.stp script instruments the scheduler and IRQ handler to determine which processes and interrupts are competing with the specified task for the cpu cycles. This script uses the '-c' or '-x' options to focus on a specific task. The script output the number of times the task migrates between processors, histograms showing the length of time on and off processor, lists of processes running while the task is off the processor, and the interrupts that occurred while the task was running.

  # stap cycle_thief.stp -c "sleep 1"

• ¶ process/errsnoop.stp - Tabulate System Call Errors
  keywords: PROCESS SYSCALL 
  

  Prints a periodic tabular report about failing system calls, by process and by syscall failure. The first optional argument specifies the reporting interval (in seconds, default 5); the second optional argument gives a screen height (number of lines in the report, default 20).

  # stap errsnoop.stp 1 10 -c "sleep 1"

• ¶ process/forktracker.stp - Trace Creation of Processes
  keywords: PROCESS SCHEDULER 
  

  The forktracker.stp script prints out a time-stamped entry showing each fork and exec operation on the machine. This can be useful to determine what process is creating a flurry of short-lived processes.

  # stap forktracker.stp -c "sleep 1"

• ¶ process/futexes.stp - System-Wide Futex Contention
  keywords: SYSCALL LOCKING FUTEX 
  

  The script watches the futex syscall on the system. On exit the futex's address, the number of contentions, and the average time for each contention on the futex are printed from lowest pid number to highest.

  # stap futexes.stp -c "sleep 1"

• ¶ process/futexes2.stp - System-Wide Shared Futex Contention
  keywords: SYSCALL LOCKING FUTEX 
  

  The script watches just shared futex syscalls on the system. On exit the futex's key, the number of contentions, and the average time for each contention on the futex are printed from lowest pid number to highest.

  # stap futexes2.stp -c "sleep 1"

• ¶ process/ltrace.stp - uprobes-based ltrace
  keywords: PROCESS 
  

  The ltrace.stp script lists calls that the designated process makes through PLTs (procedure linkage tables), generally into shared libraries.

  # stap ltrace.stp -c ls || echo PR14738

• ¶ process/migrate.stp - Track the Migration of Specific Executables
  keywords: SCHEDULER 
  

  The migrate.stp script takes an argument which is the executable name of the task it should monitor. Each time a task with that executable name migrates between processors an entry is printed with the process id (pid), the executable name, the processor off loading the task, and the process taking the task. Note that the task may or may not be executing at the time of the migration.

  # stap migrate.stp -c "sleep 1" bash

• ¶ process/mutex-contention.stp - pthread mutex contention analysis
  keywords: LOCKING 
  

  Tracks pthread-mutex initialization/use and underlying futex operations, to identify (with backtraces/symbol-names) the mutexes suffering most contention. Invoke with "-d SHLIB --ldd", perhaps with -DMAXMAPENTRIES=NNNN for some large NNNN, if the arrays overflow due to heavy activity.

  # stap mutex-contention.stp -c "sleep 1"

• ¶ process/noptrace.stp - Disable ptrace from Hierarchies of Processes
  keywords: PROCESS SECURITY GURU 
  

  Blocks ptrace(2) attempts from processes identified by stap -c/-x, as also specifiable from /proc/systemtap/stap_XXX/ control files. Processes may be added or removed from the blocked list.

  # stap -g noptrace.stp -c 'strace ls || true'

• ¶ process/pfiles.stp - Print Process File Descriptors
  keywords: PROCESS FILE 
  

  Run pfiles.stp to produce a human-readable summary of all open file descriptors of a given process. Specify the process-id as -x PID for fastest performance.

  # stap -g pfiles.stp -x $$

• ¶ process/plimit.stp - Print Resource Limits of Process
  keywords: PROCESS 
  

  The script prints a variety of resource limits for a given pid, like /proc/$$/limits on recent kernels.

  # stap -g plimit.stp $$

• ¶ process/procmod_watcher.stp - Monitor process creation/termination and module [un]loading
  keywords: PROCESS MONITORING SYSCALL TRACEPOINT 
  

  The procmod_watcher.stp script monitors calls to fork(), exec(), exit(), init_module(), and delete_module(). Event-specific details are also printed out (e.g. for exec(), the file being exec'ed). This script does not require debuginfo.

  # stap procmod_watcher.stp -c "sleep 1"

• ¶ process/psig.stp - Print Process File Descriptors
  keywords: PROCESS SIGNALS 
  

  Run psig.stp to produce a human-readable summary of the signal handling configuration of a given process. Specify the process-id as -x PID for fastest performance.

  # stap -DMAXACTION=10000 -g psig.stp -x $$

• ¶ process/pstrace_exec.stp - Print trace of process ancestors for matching exec commands
  keywords: PROCESS BACKTRACE 
  

  The pstrace_exec.stp script watches each exec operation. If the exec contains a substring that matches the script's command-line argument, it prints out that process and all of its ancestors.

  # stap pstrace_exec.stp -c "sleep 1" bash

• ¶ process/pstree.stp - Generates a process diagram in DOT form.
  keywords: PROCESS DIAGRAM 
  

  The pstree.stp script generates a process diagram in DOT form. For instance, it may be useful on a 'make' command to see all the processes that are started.

  # stap pstree.stp -c "sleep 1"

• ¶ process/rlimit_nofile.stp - Trace processes running out of file descriptors 
  keywords: LIMITS 
  

  This script watches processes being scheduled and which try to allocate a file descriptor without luck.

  # stap rlimit_nofile.stp -c "sleep 1"

• ¶ process/schedtimes.stp - Track Time Processes Spend in Various States Using Tracepoints
  keywords: PROCESS SCHEDULER TIME TRACEPOINT 
  

  The schedtimes.stp script instruments the scheduler to track the amount of time that each process spends in running, sleeping, queuing, and waiting for io. On exit the script prints out the accumulated time for each state of processes observed. Optionally, this script can be used with the '-c' or '-x' options to focus on a specific PID and its children.

  # stap schedtimes.stp -c "sleep 1"

• ¶ process/semop-watch.stp - Watch semop(2)/semtimedop(2) operations
  keywords: PROCESS LOCKING 
  

  Prints a timed trace of semop(2)/semtimedop(2) syscalls

  # stap semop-watch.stp -c 'sleep 2'

• ¶ process/sig_by_pid.stp - Signal Counts by Process ID
  keywords: SIGNALS 
  

  Print signal counts by process ID in descending order.

  # stap sig_by_pid.stp -c "sleep 1"

• ¶ process/sig_by_proc.stp - Signal Counts by Process Name
  keywords: SIGNALS 
  

  Print signal counts by process name in descending order.

  # stap sig_by_proc.stp -c "sleep 1"

• ¶ process/sigkill.stp - Track SIGKILL Signals
  keywords: SIGNALS 
  

  The script traces any SIGKILL signals. When that SIGKILL signal is sent to a process, the script prints out the signal name, the destination executable and process ID, the executable name and user ID that sents the signal.

  # stap sigkill.stp -c "sleep 1"

• ¶ process/sigmon.stp - Track a Particular Signal to a Specific Process
  keywords: SIGNALS 
  

  The script watches for a particular signal sent to a specific process. When that signal is sent to the specified process, the script prints out the PID and executable of the process sending the signal, the PID and executable name of the process receiving the signal, and the signal number and name.

  # stap sigmon.stp -c "sleep 1" SIGKILL

• ¶ process/sleepingBeauties.stp - Generate Backtraces of Threads Waiting for IO Operations
  keywords: IO SCHEDULER BACKTRACE 
  

  The script monitors the time that threads spend in waiting for IO operations (in "D" state) in the wait_for_completion function. If a thread spends over 10ms, its name and backtrace is printed, and later so is the total delay.

  # stap sleepingBeauties.stp -c "sleep 1"

• ¶ process/sleeptime.stp - Trace Time Spent in Nanosleep Syscalls
  keywords: SYSCALL NANOSLEEP 
  

  The script watches each nanosleep syscall on the system. At the end of each nanosleep syscall the script prints out a line with a timestamp in microseconds, the pid, the executable name in parentheses, the "nanosleep:" key, and the duration of the sleep in microseconds.

  # stap sleeptime.stp -c "sleep 1"

• ¶ process/strace.stp - Trace system calls
  keywords: PROCESS SYSCALL 
  

  The script loosely emulates strace, when applied to individual processes or hierarchies (via -c/-x), or the entire system (without -c/-x). A few output configuration parameters may be set with -G.

  # stap strace.stp -c "sleep 1"

• ¶ process/syscalls_by_pid.stp - System-Wide Count of Syscalls by PID
  keywords: SYSCALL 
  

  The script watches all syscall on the system. On exit the script prints a list showing the number of systemcalls executed by each PID ordered from greatest to least number of syscalls.

  # stap syscalls_by_pid.stp -c "sleep 1"

• ¶ process/syscalls_by_proc.stp - System-Wide Count of Syscalls by Executable
  keywords: SYSCALL 
  

  The script watches all syscall on the system. On exit the script prints a list showing the number of systemcalls executed by each executable ordered from greatest to least number of syscalls.

  # stap syscalls_by_proc.stp -c "sleep 1"

• ¶ process/syscalltimes - System-Wide Syscall Statistics with Filtering
  keywords: SYSCALL 
  

  Combination shell/systemtap script to measure system call counts and times. Can be filtered by process IDs, process names and users.

  # ./syscalltimes -c 'sleep 1'

• ¶ process/thread-business.stp - monitor syscall history
  keywords: PROCESS SYSCALL 
  

  Prints a periodic tabular report about the counts of syscall activity of all threads on the system, along with a textual recent-syscall-history for each

  # stap thread-business.stp -c "sleep 10"

• ¶ process/threadstacks.stp - Override default new-pthread stack sizes
  keywords: THREAD GURU 
  

  Overrides default NPTL pthread_create stack size for all new threads created by target processes. Reports one line per process when the related glibc variable __default_stacksize is updated. Moot for glibc versions that support $LIBC_PTHREAD_DEFAULT_STACKSIZE_NP.

  # stap -g threadstacks.stp -Gsize=65536 -c "sleep 1" -d `which stap`

• ¶ process/wait4time.stp - Trace Time Spent in wait4 Syscalls
  keywords: SYSCALL PROCESS 
  

  The script watches each wait4 syscall on the system. At the end of each wait4 syscall the script prints out a line with a timestamp in microseconds, the pid, the executable name in parentheses, the "wait4:" key, the duration of the wait and the PID that the wait4 was waiting for. If the waited for PID is not specified , it is "-1".

  # stap wait4time.stp -c "sleep 1"

• ¶ profiling/errno.stp - Show Which Processes and System Calls Return Errors Most Frequently
  keywords: PROFILING 
  

  On exit the errno.stp script provides a sorted list showing which combination of PID, system call, and error occur most frequently.

  # stap errno.stp -c "sleep 1"

• ¶ profiling/fntimes.stp - Show Functions Taking Longer Than Usual
  keywords: PROFILING 
  

  The fntimes.stp script monitors the execution time history of a given function family (assumed non-recursive). Each time (beyond a warmup interval) is then compared to the historical maximum. If it exceeds a certain threshold (250%), a message is printed.

  # stap fntimes.stp 'kernel.function("sys_*")' -c "sleep 7"

• ¶ profiling/functioncallcount.stp - Count Times Functions Are Called
  keywords: PROFILING FUNCTION 
  

  The functioncallcount.stp script takes one argument, a list of functions to probe. The script will run and count the number of times that each of the functions on the list is called. On exit the script will print a sorted list from most frequently to least frequently called function.

  # stap -w functioncallcount.stp "*@mm/*.c" -c "sleep 1"

• ¶ profiling/latencytap.stp - Show Reasons and Durations for Processes Sleeping
  keywords: PROFILING 
  

  The latencytap.stp script collects data on the intervals processes are deactivated (sleeping). The script categorizes the reasons for the sleeps by analyzing the backtraces and displays a sorted list of the top 20 causes from largest total sum time sleeping to smallest. The output is updated every 30 seconds. The script needs to be compiled with the '--all-modules' option to produce reasons for sleeps caused by modules. Optionally, this script can be used with the '-c' or '-x' options to focus on a specific PID.

  # stap latencytap.stp --all-modules -c "sleep 1"

• ¶ profiling/linetimes.stp - Show Time Spent on Each Line of a Function
  keywords: PROFILING 
  

  The linetimes.stp script takes two arguments: where to find the function and the function name. linetimes.stp will instrument each line in the function. It will print out the number of times that the function is called, a table with the average and maximum time each line takes, and control flow information when the script exits.

  # stap linetimes.stp kernel sys_nanosleep -c "sleep 1"

• ¶ profiling/perf.stp - Show performance ratios using perf.counter to access performance counters
  keywords: PROFILING 
  

  On exit the perf.stp script provides a sorted list showing cycles per insn, branches per insn, and cache refs per insn

  # stap perf.stp -c "find /usr/bin -name \"l*\" -printf \"%h/%f %s %Cx \%Ck%CM %Y\n\""

• ¶ profiling/periodic.stp - Show the Period of the Various Timers on the System
  keywords: PROFILING 
  

  The periodic.stp script uses the kernel.trace("timer_expire_entry") tracepoint to collect data on period and frequency of the various timers on the system. The script displays a sorted list of the timers observed on the system from most frequent to least frequent. The script needs to be compiled with the '--all-modules' option to produce list the function names. Optionally, this script can be used with a numerical argument to indicate the interval in seconds between printing output.

  # stap periodic.stp --all-modules -c "sleep 1"

• ¶ profiling/pf2.stp - Profile Kernel Functions
  keywords: PROFILING 
  

  The pf2.stp script sets up time-based sampling. Every five seconds it prints out a sorted list with the top ten kernel functions with samples.

  # stap pf2.stp -c "sleep 1"

• ¶ profiling/pf3.stp - Profile Kernel/User Functions
  keywords: PROFILING 
  

  The pf3.stp script sets up time-based sampling. Every five seconds it prints out a sorted list with the top twenty kernel and/or user functions with samples. Use any of --ldd, --all-modules, -d MODULE, -d /PATH/TO/EXEC to add more symbolic info.

  # stap pf3.stp -c "sleep 6" --all-modules --ldd

• ¶ profiling/pf4.stp - Profile Kernel/User Backtraces
  keywords: PROFILING 
  

  The pf4.stp script sets up time-based sampling. Every five seconds it prints out a sorted list with the top twenty kernel and/or user stack backtraces (on a per-cpu basis). Use any of --ldd, --all-modules, -d MODULE, -d /PATH/TO/EXEC to add more symbolic info.

  # stap pf4.stp -c "sleep 6" --all-modules --ldd

• ¶ profiling/sched_switch.stp - Display the Task Switches Happening in the Scheduler
  keywords: PROFILING FUNCTION 
  

  The sched_switch.stp script takes two arguments, first argument can be "pid" or "name" to indicate what is being passed as second argument. The script will trace the process based on pid/name and print the scheduler switches happening with the process. If no arguments are passed, it displays all the scheduler switches. This can be used to understand which tasks schedule out the current process being traced, and when it gets scheduled in again.

  # stap  sched_switch.stp -c "sleep 1"

• ¶ profiling/thread-times.stp - Profile Kernel Functions
  keywords: PROFILING 
  

  The thread-times.stp script sets up time-based sampling. Every five seconds it prints out a sorted list with the top twenty threads occupying the CPUs, broken down as a percentage of user and kernel time.

  # stap thread-times.stp -c "sleep 1"

• ¶ profiling/timeout.stp - Show Processes Doing Polling Operations
  keywords: PROFILING 
  

  The timeout.stp script is based on a blog entry (http://udrepper.livejournal.com/19041.html) mentioning a need for a tool to help developers find applications that are polling. The timeout.stp script monitors systemcall used for polling and records the systemcalls that timed out rather than returned because some action occurred. The script updates the screen once a second with the top twenty processes.

  # stap timeout.stp -c "sleep 1"

• ¶ profiling/topsys.stp - Show Processes Doing Polling Operations
  keywords: PROFILING 
  

  The topsys.stp script lists out the top twenty systemcalls for the previous 5 seconds. The output is sorted from most frequent to least frequent.

  # stap topsys.stp -c "sleep 1"

• ¶ stapgames/2048.stp - 2048
  keywords: STAPGAMES 
  

  The modern classic 2048 sliding-tiles game, using local keyboard and ansi animation.

  # stap -p4 2048.stp

• ¶ stapgames/block.stp - block breaker game
  keywords: STAPGAMES 
  

  A block game where you progressively break the ceiling blocks until clearing the level

  # stap -p4 -Itapset/ block.stp

• ¶ stapgames/eater.stp - eater game
  keywords: STAPGAMES 
  

  walk through a maze, eat stuff

  # stap -p4 -Itapset/ eater.stp

• ¶ stapgames/lifegame.stp - life game
  keywords: STAPGAMES 
  

  watch as your creation morphes into different forms

  # stap -p4 -Itapset/ lifegame.stp

• ¶ stapgames/pingpong.stp - pingpong game
  keywords: STAPGAMES 
  

  A simulated ball bounces around the terminal reflecting at the edges

  # stap -p4 -Itapset/ pingpong.stp

• ¶ virtualization/kvm_service_time.stp - Time Statistics on KVM Exit Reasons
  keywords: VIRTUALIZATION KVM 
  

  The kvm_service_time.stp script tracks the statistics about the amount of time that the processor left the guest virtual machine for each exit reason (for example fixing up a page table or handling an IO operation). When the script exits it prints out the number of times each exit reason was encountered, the total duration of time it left the guest VM, the minimum time, the average time, and the maximum time in microseconds for that exit reason. On Linux 2.6.38 and newer kernel the script can automatically determine whether it is running on Intel or AMD processors. For older kernels with a kernel.trace("kvm_exit") tracepoint that does not have the $isa parameter you can explicitly state the kvm type with a "-G kvm=intel" or "-G kvm=amd" on the command line.

  # stap kvm_service_time.stp -c "sleep 1"

• ¶ virtualization/qemu_count.stp - Tally the Number of User-Space QEMU Events
  keywords: VIRTUALIZATION QEMU KVM 
  

  The qemu_count.stp script tallies the number of times each of the user-space qemu probepoints is encountered. When the script exits, it prints a list of the number of times each user-space qemu probepoint is encountered.

  # stap qemu_count.stp -c "sleep 1"

• ¶ virtualization/qemu_io.stp - Tally the Number of User-Space QEMU IO on Each IO Port
  keywords: VIRTUALIZATION QEMU KVM IO 
  

  The qemu_io.stp script tallies the number of times each of the IO port on the guest virtual machines is touched by a input or output operation. When the script exits, it prints a count of the number of times each IO port read and written.

  # stap qemu_io.stp -c "sleep 1"