Is linux memcpy multithreaded?
Name:
Anonymous
2012-06-30 22:25
it does perform slower than windows and macosx versions..
Name:
Anonymous
2012-07-01 2:05
>>4
#define NUM_CPY_THREADS 4
HANDLE hCopyThreads[NUM_CPY_THREADS] = {0};
HANDLE hCopyStartSemaphores[NUM_CPY_THREADS] = {0};
HANDLE hCopyStopSemaphores[NUM_CPY_THREADS] = {0};
typedef struct
{
int ct;
void * src, * dest;
size_t size;
} mt_cpy_t;
mt_cpy_t mtParamters[NUM_CPY_THREADS] = {0};
DWORD WINAPI thread_copy_proc(LPVOID param)
{
mt_cpy_t * p = (mt_cpy_t * ) param;
while(1)
{
WaitForSingleObject(hCopyStartSemaphores[p->ct], INFINITE);
memcpy(p->dest, p->src, p->size);
ReleaseSemaphore(hCopyStopSemaphores[p->ct], 1, NULL);
}
return 0;
}
int startCopyThreads()
{
for(int ctr = 0; ctr < NUM_CPY_THREADS; ctr++)
{
hCopyStartSemaphores[ctr] = CreateSemaphore(NULL, 0, 1, NULL);
hCopyStopSemaphores[ctr] = CreateSemaphore(NULL, 0, 1, NULL);
mtParamters[ctr].ct = ctr;
hCopyThreads[ctr] = CreateThread(0, 0, thread_copy_proc, &mtParamters[ctr], 0, NULL);
}
return 0;
}
void * mt_memcpy(void * dest, void * src, size_t bytes)
{
//set up parameters
for(int ctr = 0; ctr < NUM_CPY_THREADS; ctr++)
{
mtParamters[ctr].dest = (char *) dest + ctr * bytes / NUM_CPY_THREADS;
mtParamters[ctr].src = (char *) src + ctr * bytes / NUM_CPY_THREADS;
mtParamters[ctr].size = (ctr + 1) * bytes / NUM_CPY_THREADS - ctr * bytes / NUM_CPY_THREADS;
}
//release semaphores to start computation
for(int ctr = 0; ctr < NUM_CPY_THREADS; ctr++)
ReleaseSemaphore(hCopyStartSemaphores[ctr], 1, NULL);
//wait for all threads to finish
WaitForMultipleObjects(NUM_CPY_THREADS, hCopyStopSemaphores, TRUE, INFINITE);
return dest;
}
int stopCopyThreads()
{
for(int ctr = 0; ctr < NUM_CPY_THREADS; ctr++)
{
TerminateThread(hCopyThreads[ctr], 0);
CloseHandle(hCopyStartSemaphores[ctr]);
CloseHandle(hCopyStopSemaphores[ctr]);
}
return 0;
}
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