Openmp并行编程的入门资料

         因为学校开设了并行程序设计的课，所以结识了Openmp编程。发现了周伟明老师的博客很好 。，收藏以下。转载地址：

http://blog.csdn.net/drzhouweiming/archive/2006/08/28/1131537.aspx

        1 问题一：下面的例子运行结果和周老师不一样，暂时想不明白：望高人指点：

        例子代码：

          #include<iostream> #include<omp.h>using namespace std;void test(){ int a = 0; clock_t t1 = clock(); for (int i = 0; i < 100000000; i++) { a = i+1; } clock_t t2 = clock(); cout<<"Time = "<<t2-t1<<endl; }int main(){ clock_t t1 = clock(); for(int i = 0; i<2: i++) { test(); } clock_t t2 = clock(); cout<<"The Total Time is "<<t2-t1<<endl; test(); return 0; }

运行之后的结果是：

Time = 570000
Time = 580000
The Total Time is  580000
Time = 280000

     2  问题二：关于sections的讲解中说 各个section里的代码都是并行执行的，并且各个section被分配到不同的线程 执行。

         例子代码为:

           1 #include<iostream> 2 #include<omp.h> 3 using namespace std; 4 int main() 5 { 6 #pragma omp parallel sections num_threads(4) 7 { 8 #pragma omp section 9 cout<<"section 1 Threadid = "<<omp_get_thread_num()<<endl; 10 #pragma omp section 11 cout<<"section 2 Threadid = "<<omp_get_thread_num()<<endl; 12 #pragma omp section 13 cout<<"section 3 Threadid = "<<omp_get_thread_num()<<endl; 14 #pragma omp section 15 cout<<"section 4 Threadid = "<<omp_get_thread_num()<<endl; 16 17 } 18 return 0; 19 } 

        运行的结果是：

                  section 1 Threadid = 3
                  section 2 Threadid = 3
                  section 3 Threadid = 3
                  section 4 Threadid = 3

 

 

由于是刚刚开始学习，暂时遇到了这两个问题，望高人指教！

loopmove dx i ; 将i置入dx寄存器inc dx ; 将dx寄存器加1mov i dx ; 将dx中的值赋回icmp i n ; 比较i和njl loop ; i 小于n时则重复循环