test/cpp/qps/limit_cores.cc

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#include "test/cpp/qps/limit_cores.h"

#include <grpc/support/cpu.h>
#include <grpc/support/log.h>
#include <grpc/support/port_platform.h>

#ifdef GPR_CPU_LINUX
#ifndef _GNU_SOURCE
#define _GNU_SOURCE
#endif
#include <sched.h>

namespace grpc {
namespace testing {

int LimitCores(const int* cores, int cores_size) {
  const int num_cores = gpr_cpu_num_cores();
  int cores_set = 0;

  cpu_set_t* cpup = CPU_ALLOC(num_cores);
  GPR_ASSERT(cpup);
  const size_t size = CPU_ALLOC_SIZE(num_cores);
  CPU_ZERO_S(size, cpup);

  if (cores_size > 0) {
    for (int i = 0; i < cores_size; i++) {
      if (cores[i] < num_cores) {
        CPU_SET_S(cores[i], size, cpup);
        cores_set++;
      }
    }
  } else {
    for (int i = 0; i < num_cores; i++) {
      CPU_SET_S(i, size, cpup);
      cores_set++;
    }
  }
  bool affinity_set = (sched_setaffinity(0, size, cpup) == 0);
  CPU_FREE(cpup);
  return affinity_set ? cores_set : num_cores;
}

}  // namespace testing
}  // namespace grpc
#else
namespace grpc {
namespace testing {

// LimitCores is not currently supported for non-Linux platforms
int LimitCores(const int*, int) { return gpr_cpu_num_cores(); }

}  // namespace testing
}  // namespace grpc
#endif