通过C++将线程固定到cpuset中的核心

Question

我有/cgroup/cpuset/set1。set1有2-5,8。我想将一个进程绑定到cpuset，然后将该进程中的线程固定到，比方说，核心4。cpuset的名称、线程名称以及我应该将线程绑定到的核心在m配置文件中。有没有C语言的API来解析cpuset？使用C代码实现钉住的正确方法是什么？

Answer 1

看一下pthread_setaffinity_np和pthread_getaffinity_np函数。

示例：

   #define _GNU_SOURCE
   #include <pthread.h>
   #include <stdio.h>
   #include <stdlib.h>
   #include <errno.h>

   #define handle_error_en(en, msg) \
           do { errno = en; perror(msg); exit(EXIT_FAILURE); } while (0)

   int
   main(int argc, char *argv[])
   {
       int s, j;
       cpu_set_t cpuset;
       pthread_t thread;

       thread = pthread_self();

       /* Set affinity mask to include CPUs 0 to 7 */

       CPU_ZERO(&cpuset);
       for (j = 0; j < 8; j++)
           CPU_SET(j, &cpuset);

       s = pthread_setaffinity_np(thread, sizeof(cpu_set_t), &cpuset);
       if (s != 0)
           handle_error_en(s, "pthread_setaffinity_np");

       /* Check the actual affinity mask assigned to the thread */

       s = pthread_getaffinity_np(thread, sizeof(cpu_set_t), &cpuset);
       if (s != 0)
           handle_error_en(s, "pthread_getaffinity_np");

       printf("Set returned by pthread_getaffinity_np() contained:\n");
       for (j = 0; j < CPU_SETSIZE; j++)
           if (CPU_ISSET(j, &cpuset))
               printf("    CPU %d\n", j);

       exit(EXIT_SUCCESS);
   }

有关更多详细信息，请参阅man page。

Answer 2

调用以下函数并传递您想要传递的任何核心ID。另外，无论你在哪里调用这个函数，都要检查它的返回值是否为1。

short CorePin(int coreID)
{
  short status=0;
  int nThreads = std::thread::hardware_concurrency();
  //std::cout<<nThreads;
  cpu_set_t set;
  std::cout<<"\nPinning to Core:"<<coreID<<"\n";
  CPU_ZERO(&set);

  if(coreID == -1)
  {
    status=-1;
    std::cout<<"CoreID is -1"<<"\n";
    return status;
  }

  if(coreID > nThreads)
  {
    std::cout<<"Invalid CORE ID"<<"\n";
    return status;
  }

  CPU_SET(coreID,&set);
  if(sched_setaffinity(0, sizeof(cpu_set_t), &set) < 0)
  {
    std::cout<<"Unable to Set Affinity"<<"\n";
    return -1;
  }
  return 1;
}