Slajd8 (27)

Explicit Threading

np. P0$1X threads (Pthreads), Windows Threads

ttinclude <stdio.h> ttinclude <pthreads.h>

ttdefine NUM_RECTS 100000 ttdefine NUM_THREADS 4

double gArea = 0.0; pthread_mutex_t gLock;

void *threadFunction(void *pArg) { int myNum = *((int *) pArg) ;

double partialHeight = 0.0, lWidth =1.0 / NUM_RECTS, x;

for (int i = myNum; i < NUM_RECTS; i += NUM_THREADS) {

X = (i + 0.5f)    / NUM_RECTS;

partialHeight += 4.0f / (l.Of + x * x);

}

pthread_mutex_lock(SgLock) ;

gArea += partialHeigth * lWidth; pthread_mutex_unlock(&gLock);

>

/* cd. następny slajd */

T2-2 - Modele obliczeń rozproszonych Marek Nowak 8