第3讲并行编程模型概述与pthread

pthread编程概#include<stdio.h>staticlongnum_steps=100000;doublestep;intmain(intargc,char*{inti;doublex,pi,sum=for(i=1;i<=num_steps;i++){x=(i-sum=sum+}pi=step*returnEXIT_SUCCESS;}PthreadAF时，将首先从A的堆栈空间S中为F的局部变量分配空间。A在执行F的过程中，可以程序的全局数据、S中数据。Fstatic变量(为什么？)2IO#include<time.h>#include<stdio.h>#include<stdlib.h>#include<unistd.h>#includepthread.h> doublestep,sum=0.0;inti;sum=for(i=1;i<=num_steps;i++){x=(i-sum=sum+}returnstep*}inttotalThread; mtx; myID,lbound,ubound,i,loc_size;doublex;myID=totalThread;if(totalThread<(*(int*)arg))pthread_cond_wait(&cond,&mtx);elsepthread_cond_broadcast(&cond);loc_size=(num_steps+totalThread-1)/totalThread;lbound=1+loc_size*myID;ubound=lbound+loc_size-if(ubound>num_steps)ubound=num_steps;for(i=lbound;i<=ubound;i++){x=(i-0.5)*step;sum=sum+4.0/(1.0+x*x);}} doublesum=step=1.0/(double)num_steps;totalThread=0;if(thread_num>Max_Thread_Num)thread_num=Max_Thread_Num;for(i=0;i<thread_num;i++)for(i=0;i<thread_num;i++)pthread_join(threads[i],NULL);returnstep*} myID,lbound,ubound,i,loc_size;doubleloc_sum,x;myID=totalThread;if(totalThread<(*(int*)arg))pthread_cond_wait(&cond,&mtx);elsepthread_cond_broadcast(&cond);loc_size=(num_steps+totalThread-1)/totalThread;lbound=1+loc_size*myID;ubound=lbound+loc_size-if(ubound>num_steps)ubound=num_steps;loc_sum=0;{x=(i-loc_sum=loc_sum+}sum=sum+loc_sum;return} doublesum=step=1.0/(double)num_steps;totalThread=0;if(thread_num>Max_Thread_Num)thread_num=Max_Thread_Num;for(i=0;i<thread_num;i++)for(i=0;i<thread_num;i++)pthread_join(threads[i],NULL);returnstep*}intmain(intargc,char*{doublepi=serial_PI();serial_cost=te.tv_sec-ts.tv_sec+(double)(te.tv_nsec-ts.tv_nsec)/NANO;printf("serial:PI=%20.18f cost=%-15.10f\n",pi,serial_cost);clock_gettime(CLOCK_REALTIME,&ts);pi=pthread_PI_syn();syn_cost=te.tv_sec-ts.tv_sec+(double)(te.tv_nsec-ts.tv_nsec)/NANO; pi=pthread_PI_a