多线程程序正在阻塞

Question

嗨,我正在尝试在C中编写一个多线程程序,我使用4个线程来处理浮点数组的某些计算.所以,我开始只创建4个线程并使用一些参数来定义线程将在哪个数组部分工作.那时程序运行正常.

现在,我尝试仅使用加载和存储指令(256位Intel内在函数).然后,程序永远不会完成,虽然看起来线程例程正在完成他们的工作.

void *routine(void *thread_info)
{
   int n;
   unsigned t_start,t_stop;
   unsigned ind1, ind2, ind3;
   float *arr_in , *arr_out;
   struct thread_data *mydata;

   mydata = (struct thread_data*) thread_info;
   t_start = mydata->start;
   t_stop  = mydata->stop;
   arr_in  = mydata->input;
   arr_out = mydata->output;

   for (n = t_start; n < t_stop; n += 8)
   {  
      ind1 = 256 + n;
      ind2 = 512 + n;

      vec_a = _mm256_load_ps((float *) (&arr_in[n   ]) );
      vec_b = _mm256_load_ps((float *) (&arr_in[ind1]) );
      vec_c = _mm256_load_ps((float *) (&arr_in[ind2]) );

      _mm256_store_ps((float *) (&arr_out[n   ]), (vec_a) );
      _mm256_store_ps((float *) (&arr_out[ind1]), (vec_b) );
      _mm256_store_ps((float *) (&arr_out[ind2]), (vec_c) );
    }   
    printf("EXECUTION FINISHED ===== Thread : %u \n",t_start);
    pthread_exit(NULL);
}

void foo(float* in,float* out)
{
   unsigned t,i=0;
   for(t=0;t<256;t+=64)
   {
      thread_data_array[i].start    = t;
      thread_data_array[i].stop = t+QUARTER;
      thread_data_array[i].input    = in;
      thread_data_array[i].output   = out;
      pthread_create(&threads[i],NULL,routine,(void*)&thread_data_array[i]);
      i++;
   }
   pthread_exit(NULL);
}

int main()
{
   float *data1;
   float *data2;

   posix_memalign((void**)&data1, 32, 1024 * sizeof(float));
   posix_memalign((void**)&data2, 32, 1024 * sizeof(float));

   Load_inputs(reals,imags);//load data into the two arrays
   foo(data1,data2);
   printf("PROGRAM EXECUTION FINISHED");
   return EXIT_SUCCESS;
}

编译很好没有错误,但执行给我以下内容:

EXECUTION FINISHED ===== Thread : 0 
EXECUTION FINISHED ===== Thread : 64 
EXECUTION FINISHED ===== Thread : 128 
EXECUTION FINISHED ===== Thread : 192

该计划没有终止,仍然缺失 PROGRAM EXECUTION FINISHED

Answer 1

在你的foo函数中,你调用pthread_exit(NULL);哪个将立即终止主线程(foo从主线程调用).这就是为什么你没有在输出中看到"PROGRAM EXECUTION FINISHED"的原因,主线程永远不会有机会将其打印出来,因为它已经终止了foo.你要做的是加入线程,pthread_join使主线程等待其他线程完成.