[c++]无锁队列

/* * lock free queue, thread safe * this paper "A practical nonblocking queue algorithm using compare-and-swap" provide the main idea * queue.hpp * enqueue into the tail * dequeue from head */#ifndef __QUEUE_HPP__#define __QUEUE_HPP__typedef int int_t;typedef long long int_2t;#define sync_get_2t(val_ptr)__sync_fetch_and_add((val_ptr),0)#define sync_inc_t(val_ptr)__sync_fetch_and_add((val_ptr),1)#define sync_dec_t(val_ptr)__sync_fetch_and_sub((val_ptr),1)#define sync_cas_2t(val_ptr,old_val,new_val)__sync_bool_compare_and_swap((val_ptr),(old_val),(new_val))#define int_2t_low_part_ptr(x)((int_t*)(&(x)))#define int_2t_high_part_ptr(x)(((int_t*)(&(x)))+1)#define int_2t_low_part(x)(*(int_2t_low_part_ptr(x)))#define int_2t_high_part(x)(*(int_2t_high_part_ptr(x)))template<typename T>class queue{private:T *m_data_queue;int_2t *m_free_array;int_2t *m_data_array;int_2t m_free_head;int_2t m_free_tail;int_2t m_data_head;int_2t m_data_tail;const int_t m_capacity;int_t m_size;public:queue(const int_t size=1024):m_capacity(size+1){if(m_capacity>1){m_data_queue = new T[m_capacity-1];m_free_array = new int_2t[m_capacity];m_data_array = new int_2t[m_capacity];int_2t_low_part(m_free_tail)=m_capacity-1;int_2t_high_part(m_free_tail)=0;m_free_head=0;m_data_head=0;m_data_tail=0;m_size=0;for(int i=0;i<m_capacity;++i){int_2t_low_part(m_free_array[i])=i;int_2t_high_part(m_free_array[i])=0;int_2t_low_part(m_data_array[i])=-1;int_2t_high_part(m_data_array[i])=0;}int_2t_low_part(m_free_array[m_capacity-1])=-1;}}~queue(){if(m_capacity>1){delete [] m_data_queue;delete [] m_free_array;delete [] m_data_array;}}//enqueue one free node back to the tailbool enqueue_free(const T *p){int_t index = p - m_data_queue;while(true){int_2t tail = sync_get_2t(&m_free_tail);int_2t head = sync_get_2t(&m_free_head);int_t tail_ptr = int_2t_low_part(tail);int_t head_ptr = int_2t_low_part(head);int_t tail_next_ptr = tail_ptr+1;if(tail_next_ptr==m_capacity) tail_next_ptr=0;if(tail!=sync_get_2t(&m_free_tail)) continue;if(tail_next_ptr==head_ptr) return false;int_2t tail_ptr_old_val = sync_get_2t(&(m_free_array[tail_ptr]));int_t tail_ptr_old_val_ptr = int_2t_low_part(tail_ptr_old_val);if(tail_ptr_old_val_ptr==-1){int_2t tail_ptr_new_val = tail_ptr_old_val;int_2t_low_part(tail_ptr_new_val) = index;int_2t_high_part(tail_ptr_new_val) = int_2t_high_part(tail_ptr_old_val)+1;if(sync_cas_2t(&(m_free_array[tail_ptr]),tail_ptr_old_val,tail_ptr_new_val)){int_2t tail_new = tail;int_2t_low_part(tail_new)=tail_next_ptr;int_2t_high_part(tail_new)=int_2t_high_part(tail)+1;sync_cas_2t(&m_free_tail,tail,tail_new);return true;}}else{int_2t tail_new = tail;int_2t_low_part(tail_new)=tail_next_ptr;int_2t_high_part(tail_new)=int_2t_high_part(tail)+1;sync_cas_2t(&m_free_tail,tail,tail_new);}}}//dequeue one free node from the headbool dequeue_free(T *(&p)){while(true){int_2t head = sync_get_2t(&m_free_head);int_2t tail = sync_get_2t(&m_free_tail);int_t head_ptr = int_2t_low_part(head);int_t tail_ptr = int_2t_low_part(tail);if(head!=sync_get_2t(&m_free_head)) continue;if(head_ptr==tail_ptr) return false;int_2t head_ptr_old_val = sync_get_2t(&(m_free_array[head_ptr]));int_t head_ptr_old_val_ptr = int_2t_low_part(head_ptr_old_val);if(head_ptr_old_val_ptr!=-1){int_2t head_ptr_new_val = head_ptr_old_val;int_2t_low_part(head_ptr_new_val)=-1;int_2t_high_part(head_ptr_new_val)=int_2t_high_part(head_ptr_old_val)+1;if(sync_cas_2t(&(m_free_array[head_ptr]),head_ptr_old_val,head_ptr_new_val)){int_2t head_new = head;int_t head_new_ptr = int_2t_low_part(head_new)+1;if(head_new_ptr==m_capacity) head_new_ptr=0;int_2t_low_part(head_new)=head_new_ptr;int_2t_high_part(head_new)=int_2t_high_part(head)+1;sync_cas_2t(&m_free_head,head,head_new);p=head_ptr_old_val_ptr + m_data_queue;return true;}}else{int_2t head_new = head;int_t head_new_ptr = int_2t_low_part(head_new)+1;if(head_new_ptr==m_capacity) head_new_ptr=0;int_2t_low_part(head_new)=head_new_ptr;int_2t_high_part(head_new)=int_2t_high_part(head)+1;sync_cas_2t(&m_free_head,head,head_new);}}}//enqueue one data node back to the tailbool enqueue_data(const T *p){int_t index = p - m_data_queue;while(true){int_2t tail = sync_get_2t(&m_data_tail);int_2t head = sync_get_2t(&m_data_head);int_t tail_ptr = int_2t_low_part(tail);int_t head_ptr = int_2t_low_part(head);int_t tail_next_ptr = tail_ptr+1;if(tail_next_ptr==m_capacity) tail_next_ptr=0;if(tail!=sync_get_2t(&m_data_tail)) continue;if(tail_next_ptr==head_ptr) return false;int_2t tail_ptr_old_val = sync_get_2t(&(m_data_array[tail_ptr]));int_t tail_ptr_old_val_ptr = int_2t_low_part(tail_ptr_old_val);if(tail_ptr_old_val_ptr==-1){int_2t tail_ptr_new_val = tail_ptr_old_val;int_2t_low_part(tail_ptr_new_val) = index;int_2t_high_part(tail_ptr_new_val) = int_2t_high_part(tail_ptr_old_val)+1;if(sync_cas_2t(&(m_data_array[tail_ptr]),tail_ptr_old_val,tail_ptr_new_val)){int_2t tail_new = tail;int_2t_low_part(tail_new)=tail_next_ptr;int_2t_high_part(tail_new)=int_2t_high_part(tail)+1;sync_cas_2t(&m_data_tail,tail,tail_new);sync_inc_t(&m_size);return true;}}else{int_2t tail_new = tail;int_2t_low_part(tail_new)=tail_next_ptr;int_2t_high_part(tail_new)=int_2t_high_part(tail)+1;sync_cas_2t(&m_data_tail,tail,tail_new);}}}//dequeue one data node from the headbool dequeue_data(T *(&p)){while(true){int_2t head = sync_get_2t(&m_data_head);int_2t tail = sync_get_2t(&m_data_tail);int_t head_ptr = int_2t_low_part(head);int_t tail_ptr = int_2t_low_part(tail);if(head!=sync_get_2t(&m_data_head)) continue;if(head_ptr==tail_ptr) return false;int_2t head_ptr_old_val = sync_get_2t(&(m_data_array[head_ptr]));int_t head_ptr_old_val_ptr = int_2t_low_part(head_ptr_old_val);if(head_ptr_old_val_ptr!=-1){int_2t head_ptr_new_val = head_ptr_old_val;int_2t_low_part(head_ptr_new_val)=-1;int_2t_high_part(head_ptr_new_val)=int_2t_high_part(head_ptr_old_val)+1;if(sync_cas_2t(&(m_data_array[head_ptr]),head_ptr_old_val,head_ptr_new_val)){int_2t head_new = head;int_t head_new_ptr = int_2t_low_part(head_new)+1;if(head_new_ptr==m_capacity) head_new_ptr=0;int_2t_low_part(head_new)=head_new_ptr;int_2t_high_part(head_new)=int_2t_high_part(head)+1;sync_cas_2t(&m_data_head,head,head_new);p=head_ptr_old_val_ptr + m_data_queue;sync_dec_t(&m_size);return true;}}else{int_2t head_new = head;int_t head_new_ptr = int_2t_low_part(head_new)+1;if(head_new_ptr==m_capacity) head_new_ptr=0;int_2t_low_part(head_new)=head_new_ptr;int_2t_high_part(head_new)=int_2t_high_part(head)+1;sync_cas_2t(&m_data_head,head,head_new);}}}const int_t size(){ return m_size; }};#endif

------------------------------------------

测试程序

-----------------------------------------

#include<iostream>#include<unistd.h>#include<pthread.h>#include"queue.hpp"using namespace std;#define QUEUE_SIZE100#define THREAD_NUM100#define LOOP_NUM1000000queue<long long> q(QUEUE_SIZE);long long total=1;void* producer(void*p){long long *d;for(int i=0;i<LOOP_NUM;++i){while(q.dequeue_free(d)==false);*d=__sync_fetch_and_add(&total,1);while(q.enqueue_data(d)==false);}}void* consumer(void*p){long long*d;long long*cnt=(long long*)p;for(int i=0;i<LOOP_NUM;++i){while(q.dequeue_data(d)==false);*cnt += *d;while(q.enqueue_free(d)==false);}}int main(){pthread_t threads[THREAD_NUM*2];long long cnt[THREAD_NUM];long long sum=0;long long expect=THREAD_NUM*LOOP_NUM;for(int i=0;i<THREAD_NUM;++i) cnt[i]=0;for(int i=0;i<THREAD_NUM;++i){if(pthread_create(threads+i,NULL,producer,NULL)) cout << "Error at create thread " << i << endl;}for(int i=0;i<THREAD_NUM;++i){if(pthread_create(threads+i+THREAD_NUM,NULL,consumer,cnt+i)) cout << "Error at create thread " << i+THREAD_NUM << endl;}for(int i=0;i<THREAD_NUM*2;++i){if(pthread_join(threads[i],NULL)) cout << "Error at join thread " << i << endl;}for(int i=0;i<THREAD_NUM;++i){sum+=cnt[i];cout << i << "=" << cnt[i] << endl;}cout << "Actual Value : " << sum << endl;expect=(expect*(expect+1))/2;cout << "Expect Value : " << expect << endl;return 0;}