pthread多线程加速示例(大型矩阵乘法)
#include
#include
#include "MatrixLib.h"
#pragma comment(lib,"MatrixLib.lib")
#pragma warning(disable:4996)
void checkResult(char* str, int value, FILE* pflog)
{
if (value != 0)
{
fprintf(pflog, "Failed with %d at %s", value, str);
exit(1);
}
}
typedef struct
{
FILE* pflog;
double** R;
double** A;
double** B;
int start_row;
int end_row;
int num_col;
} threadParm_t;
void *oneThread(void *param)
{
threadParm_t *p = (threadParm_t *)param;
fprintf(p->pflog, "# Thread \'%.8X %.8X\' is now running.\n", getpid());
double** R = p->R;
double** A = p->A;
double** B = p->B;
int start_row = p->start_row;
int end_row = p->end_row;
int num_col = p->num_col;
double tmp;
for (int i = start_row; i < end_row; ++i)
{
for (int j = 0; j < num_col; ++j)
{
tmp = 0;
for (int k = 0; k < num_col; ++k)
{
tmp += A[i][k] * B[j][k];
}
R[i][j] = tmp;
}
}
return NULL;
}
void OneTry(const int N, const int C,FILE* pflog)
{
fprintf(pflog,"== %4d * %4d Matrix Multiply, %d Threads. ==\n", N, N, C);
clock_t start = clock();
double** X = NewSquareMatrix(N);
double** Y = NewSquareMatrix(N);
double** Z = NewSquareMatrix(N);
TransformSquareMat(Z, N); // 转置一次
int start_row = 0, end_row = 0;
int inc_row = N / C;
end_row = start_row + inc_row;
int i, rc;
pthread_t* threads = new pthread_t[C];
threadParm_t* tparams = new threadParm_t[C];
for (i = 0; i < C; ++i)
{
tparams[i].pflog = pflog;
tparams[i].R = X;
tparams[i].A = Y;
tparams[i].B = Z;
tparams[i].num_col = N;
tparams[i].start_row = start_row;
tparams[i].end_row = end_row;
start_row = end_row + 1;
end_row += inc_row;
rc = pthread_create(&threads[i], NULL, oneThread, & tparams[i]);
checkResult("!! pthread_create()\n", rc,pflog);
fprintf(pflog,"********** %2d of %2d threads created **********\n", i + 1,C);
}
fprintf(pflog,"@ Waiting for worker threads' end...\n");
int* status = new int[C];
for (i = 0; i < C; ++i)
{
rc = pthread_join(threads[i], (void**)(&status[i]));
checkResult("!! pthread_join()\n", rc,pflog);
}
fprintf(pflog,"@ Check all thread's results\n");
for (i = 0; i < C; ++i)
{
if (status[i] != NULL)
{
fprintf(pflog,"!! Unexpected thread status\n");
}
}
//TransformSquareMat(Z, N); // 恢复
SafeDeleteSquareMat(X, N);
SafeDeleteSquareMat(Y, N);
SafeDeleteSquareMat(Z, N);
clock_t finish = clock();
fprintf(pflog,"@ All finished. Total time:%.8f(sec).\n\n",(finish-start)/(1.0*CLOCKS_PER_SEC));
}
int main(int argc, char **argv)
{
FILE* pflog = fopen("trace_log.txt", "a");
const int N = 4096, C = 32;
printf("Matrix N=%d,Thread C=%d, now running...", N, C);
time_t rawtime;
time(&rawtime);
tm* tminfo = localtime(&rawtime);
fprintf(pflog, "NEW LOG @%s", asctime(tminfo));
OneTry(4096,32,pflog);
fflush(pflog);
fclose(pflog);
printf("finshed!\n");
system("pause");
return 0;
} cmnheader.h同之前有关pthread的文章
MatrixLib.dll是自己写的，代码如下
Matrix.h文件内容
/*
* 矩阵操作的定义
* 用于导出DLL
*/
#ifndef MATRIX_LIB_H
#define MATRIX_LIB_H
// 兼容C版本导出符号
#ifdef __cplusplus
// 定义DLLEXPORT时启用导出
#ifdef DLLEXPORT
#define MAPI extern "C" __declspec (dllexport)
// 未定义DLLEXPORT宏时即为导入
#else /* DLLEXPORT */
#define MAPI extern "C" __declspec (dllimport)
#endif /* DLLEXPORT */
#else /* __cplusplus */
#ifdef DLLIMPORT
#define MAPI __declspec (dllexport)
#else /* DLLIMPORT */
#define MAPI __declspec (dllimport)
#endif /* DLLIMPORT */
#endif /* __cplusplus */
#include
#include
#include
MAPI double** NewSquareMatrix(const int n);
MAPI void TransformSquareMat(double** mat,const int n);
MAPI double SafeDeleteSquareMat(double** mat, const int n);
MAPI double SquareMatMultiply(double** R, double** A, double** B, const int n);
MAPI double SquareMatMultiplyTrans(double** R,double** A,double** B,const int n);
MAPI double RndInitSquareMat(double **mat, const int n);
MAPI void TraceLogInfo(char* strInfo, FILE* pflog = stdout);
MAPI void TraceLogDuration(double durationTime, FILE* pflog = stdout);
#endif /* MATRIX_LIB_H */ MatrixLib.cpp文件内容
// 启用DLLEXPORT宏定义，声明将要导出DLL
#define DLLEXPORT
#include "MatrixLib.h"
// 创建一个n阶方阵mat并分配内存，返回首地址
MAPI double **NewSquareMatrix(const int n)
{
double** mat = new double*[n];
for (int i = 0; i < n; ++i)
{
mat[i] = new double[n];
}
return mat;
}
// 方阵的转置
MAPI void TransformSquareMat(double** mat,const int n)
{
double tmp;
for(int i=0;i日志片段
NEW LOG @Fri Apr 18 16:42:44 2014
== 4096 * 4096 Matrix Multiply, 32 Threads. ==
********** 1 of 32 threads created **********
********** 2 of 32 threads created **********
********** 3 of 32 threads created **********
********** 4 of 32 threads created **********
# Thread '00000C48 00B728A0' is now running.
# Thread '00000C48 00B72B80' is now running.
********** 5 of 32 threads created **********
# Thread '00000C48 00B72E60' is now running.
# Thread '00000C48 00B73140' is now running.
********** 6 of 32 threads created **********
********** 7 of 32 threads created **********
********** 8 of 32 threads created **********
********** 9 of 32 threads created **********
********** 10 of 32 threads created **********
********** 11 of 32 threads created **********
********** 12 of 32 threads created **********
********** 13 of 32 threads created **********
********** 14 of 32 threads created **********
********** 15 of 32 threads created **********
********** 16 of 32 threads created **********
********** 17 of 32 threads created **********
# Thread '00000C48 00B73640' is now running.
********** 18 of 32 threads created **********
********** 19 of 32 threads created **********
********** 20 of 32 threads created **********
********** 21 of 32 threads created **********
********** 22 of 32 threads created **********
********** 23 of 32 threads created **********
********** 24 of 32 threads created **********
********** 25 of 32 threads created **********
********** 26 of 32 threads created **********
********** 27 of 32 threads created **********
********** 28 of 32 threads created **********
********** 29 of 32 threads created **********
********** 30 of 32 threads created **********
********** 31 of 32 threads created **********
********** 32 of 32 threads created **********
@ Waiting for worker threads' end...
# Thread '00000C48 00B73920' is now running.
# Thread '00000C48 00B731E8' is now running.
# Thread '00000C48 00B73290' is now running.
# Thread '00000C48 00B73338' is now running.
# Thread '00000C48 00B74248' is now running.
# Thread '00000C48 00B747F0' is now running.
# Thread '00000C48 00B74AD0' is now running.
# Thread '00000C48 00B74DB0' is now running.
# Thread '00000C48 00B78AB0' is now running.
# Thread '00000C48 00B7B8A8' is now running.
# Thread '00000C48 00B7BAA0' is now running.
# Thread '00000C48 00B7B950' is now running.
# Thread '00000C48 00B704C0' is now running.
# Thread '00000C48 00B781E0' is now running.
# Thread '00000C48 00B7ACD8' is now running.
# Thread '00000C48 00B7AED0' is now running.
# Thread '00000C48 00B7AE28' is now running.
# Thread '00000C48 00B7B170' is now running.
# Thread '00000C48 00B7B800' is now running.
# Thread '00000C48 00B7AD80' is now running.
# Thread '00000C48 00B7B9F8' is now running.
# Thread '00000C48 00B7B218' is now running.
# Thread '00000C48 00B7AF78' is now running.
# Thread '00000C48 00B7B020' is now running.
# Thread '00000C48 00B7B0C8' is now running.
# Thread '00000C48 00B7B2C0' is now running.
# Thread '00000C48 00B74510' is now running.
@ Check all thread's results
@ All finished. Total time:44.18600000(sec).