Gem5的基础知识（1）

1、通过下面的命令可以查看se模式和fs模式下的各种可用选项（se和fs的输出内容基本一致）

se：

./build/X86/gem5.opt ./configs/example/se.py -h

fs：

./build/X86/gem5.opt ./configs/example/fs.py -h

输出内容：

gem5 Simulator System.  http://gem5.orggem5 is copyrighted software; use the --copyright option for details.gem5 compiled Mar  2 2016 15:22:55gem5 started Jul 15 2016 10:09:52gem5 executing on cyh-Lenovocommand line: ./build/X86/gem5.opt ./configs/example/se.py -hUsage: se.py [options]Options:  -h, --help            show this help message and exit  --list-cpu-types      List available CPU types  --cpu-type=CPU_TYPE   type of cpu to run with  --checker               -n NUM_CPUS, --num-cpus=NUM_CPUS  --sys-voltage=SYS_VOLTAGE                        Top-level voltage for blocks running at system                        power supply  --sys-clock=SYS_CLOCK                        Top-level clock for blocks running at system                        speed  --cpu-clock=CPU_CLOCK                        Clock for blocks running at CPU speed  --smt                                        Only used if multiple programs                        are specified. If true,                       then the                        number of threads per cpu is same as the                        number of programs.  --list-mem-types      List available memory types  --mem-type=MEM_TYPE   type of memory to use  --mem-channels=MEM_CHANNELS                        number of memory channels  --mem-size=MEM_SIZE   Specify the physical memory size (single memory)  --caches                --l2cache               --fastmem               --num-dirs=NUM_DIRS     --num-l2caches=NUM_L2CACHES  --num-l3caches=NUM_L3CACHES  --l1d_size=L1D_SIZE     --l1i_size=L1I_SIZE     --l2_size=L2_SIZE       --l3_size=L3_SIZE       --l1d_assoc=L1D_ASSOC  --l1i_assoc=L1I_ASSOC  --l2_assoc=L2_ASSOC     --l3_assoc=L3_ASSOC     --cacheline_size=CACHELINE_SIZE  --ruby                  -m TICKS, --abs-max-tick=TICKS                        Run to absolute simulated tick specified including                        ticks from a restored checkpoint  --rel-max-tick=TICKS  Simulate for specified number of ticks relative to the                        simulation start tick (e.g. if restoring a checkpoint)  --maxtime=MAXTIME     Run to the specified absolute simulated time in                        seconds  -I MAXINSTS, --maxinsts=MAXINSTS                        Total number of instructions to                        simulate (default: run forever)  --work-item-id=WORK_ITEM_ID                        the specific work id for exit & checkpointing  --work-begin-cpu-id-exit=WORK_BEGIN_CPU_ID_EXIT                        exit when work starts on the specified cpu  --work-end-exit-count=WORK_END_EXIT_COUNT                        exit at specified work end count  --work-begin-exit-count=WORK_BEGIN_EXIT_COUNT                        exit at specified work begin count  --init-param=INIT_PARAM                        Parameter available in simulation with m5                        initparam  --simpoint-profile    Enable basic block profiling for SimPoints  --simpoint-interval=SIMPOINT_INTERVAL                        SimPoint interval in num of instructions  --take-checkpoints=TAKE_CHECKPOINTS                        <M,N> take checkpoints at tick M and every N ticks                        thereafter  --max-checkpoints=MAX_CHECKPOINTS                        the maximum number of checkpoints to drop  --checkpoint-dir=CHECKPOINT_DIR                        Place all checkpoints in this absolute directory  -r CHECKPOINT_RESTORE, --checkpoint-restore=CHECKPOINT_RESTORE                        restore from checkpoint <N>  --checkpoint-at-end   take a checkpoint at end of run  --work-begin-checkpoint-count=WORK_BEGIN_CHECKPOINT_COUNT                        checkpoint at specified work begin count  --work-end-checkpoint-count=WORK_END_CHECKPOINT_COUNT                        checkpoint at specified work end count  --work-cpus-checkpoint-count=WORK_CPUS_CHECKPOINT_COUNT                        checkpoint and exit when active cpu count is reached  --restore-with-cpu=RESTORE_WITH_CPU                        cpu type for restoring from a checkpoint  --repeat-switch=REPEAT_SWITCH                        switch back and forth between CPUs with period <N>  -s STANDARD_SWITCH, --standard-switch=STANDARD_SWITCH                        switch from timing to Detailed CPU after warmup period                        of <N>  -p PROG_INTERVAL, --prog-interval=PROG_INTERVAL                        CPU Progress Interval  -W WARMUP_INSTS, --warmup-insts=WARMUP_INSTS                        Warmup period in total instructions (requires                        --standard-switch)  --bench=BENCH         base names for --take-checkpoint and --checkpoint-                        restore  -F FAST_FORWARD, --fast-forward=FAST_FORWARD                        Number of instructions to fast forward before                        switching  -S, --simpoint        Use workload simpoints as an instruction offset for                        --checkpoint-restore or --take-checkpoint.  --at-instruction      Treat value of --checkpoint-restore or --take-                        checkpoint as a                 number of                        instructions.  -c CMD, --cmd=CMD     The binary to run in syscall emulation mode.  -o OPTIONS, --options=OPTIONS                        The options to pass to the binary, use " "                        around the entire string  -i INPUT, --input=INPUT                        Read stdin from a file.  --output=OUTPUT       Redirect stdout to a file.  --errout=ERROUT       Redirect stderr to a file.

2、在se模式下，执行自己写的程序

#include <stdio.h>int main(){    printf("hello world!\n");    return 0;}

编译：./build/X86/gem5.opt ./configs/example/se.py -c ./gem5_test/helloworld

注意：模拟器只能运行静态编译的程序，不能是动态编译，所以在编译的时候加上-static

运行helloworld

./build/X86/gem5.opt ./configs/example/se.py -c ./gem5_test/helloworld

输出结果：

Global frequency set at 1000000000000 ticks per second0: system.remote_gdb.listener: listening for remote gdb #0 on port 7000**** REAL SIMULATION ****info: Entering event queue @ 0.  Starting simulation...hello world!hack: be nice to actually delete the event hereExiting @ tick 5461500 because target called exit()

3、指定CPU的个数

 ./build/X86/gem5.opt ./configs/example/se.py --cmd=./gem5_test/fft --num-cpus=4

输出结果：

gem5 Simulator System.  http://gem5.orggem5 is copyrighted software; use the --copyright option for details.gem5 compiled Mar  2 2016 15:22:55gem5 started Jul 15 2016 15:23:34gem5 executing on cyh-Lenovocommand line: ./build/X86/gem5.opt ./configs/example/se.py --cmd=./gem5_test/fft --num-cpus=4Global frequency set at 1000000000000 ticks per second0: system.remote_gdb.listener: listening for remote gdb #0 on port 70000: system.remote_gdb.listener: listening for remote gdb #1 on port 70010: system.remote_gdb.listener: listening for remote gdb #2 on port 70020: system.remote_gdb.listener: listening for remote gdb #3 on port 7003**** REAL SIMULATION ****info: Entering event queue @ 0.  Starting simulation...fatal: syscall set_tid_address (#218) unimplemented. @ cycle 1085000[unimplementedFunc:build/X86/sim/syscall_emul.cc, line 83]Memory Usage: 636228 KBytes

注意：这里的fft是parsec benchmark中的一个benchmark。