C++: How to Get Per-Core CPU Usage in Mac

C++: Mac環境でコア単位のCPU使用率を測定する

 

環境

• OS X: 10.9

 

コード

#include <stdio.h>
#include <unistd.h>
#include <mach/mach_host.h>
#include <mach/processor_info.h>
#include <iostream>

using namespace std;

class CpuUsage {
 public:
  CpuUsage(int core): core_(core) {
    prev = updated_ticks_(core);
  }

  float get() {
    Ticks t = updated_ticks_(core_);
    unsigned long long int used = t.used() - prev.used();
    unsigned long long int total = t.total() - prev.total();
    prev = t;
    return (float)used / (float)total * 100.0f;
  }

 private:
  struct Ticks {
    unsigned long long int usertime;
    unsigned long long int nicetime;
    unsigned long long int systemtime;
    unsigned long long int idletime;

    unsigned long long int used() { return usertime + nicetime + systemtime; }
    unsigned long long int total() { return usertime + nicetime + systemtime + idletime; }
  } prev;

  int core_;

  Ticks updated_ticks_(int core) {
    unsigned int cpu_count;
    processor_cpu_load_info_t cpu_load;
    mach_msg_type_number_t cpu_msg_count;

    int rc =  host_processor_info(
      mach_host_self( ),
      PROCESSOR_CPU_LOAD_INFO,
      &cpu_count,
      (processor_info_array_t *) &cpu_load,
      &cpu_msg_count
    );
    if (rc != 0) {
      printf("Error: failed to scan processor info (rc=%d)\n", rc);
      exit(1);
    }

    if (core < 0 || cpu_count <= core) {
      printf("Error: invalid core number: %d\n", core);
      exit(1);
    }
    unsigned long long int usertime = cpu_load[core].cpu_ticks[CPU_STATE_USER];
    unsigned long long int nicetime = cpu_load[core].cpu_ticks[CPU_STATE_NICE];
    unsigned long long int systemtime = cpu_load[core].cpu_ticks[CPU_STATE_SYSTEM];
    unsigned long long int idletime = cpu_load[core].cpu_ticks[CPU_STATE_IDLE];

    Ticks t = {usertime, nicetime, systemtime, idletime};
    return t;
  }

};

int main() {
  CpuUsage a(0), b(1), c(2), d(3);
  sleep(1);
  printf("%6.2f, %6.2f, %6.2f, %6.2f\n", a.get(), b.get(), c.get(), d.get());
  sleep(1);
  printf("%6.2f, %6.2f, %6.2f, %6.2f\n", a.get(), b.get(), c.get(), d.get());
  sleep(1);
  printf("%6.2f, %6.2f, %6.2f, %6.2f\n", a.get(), b.get(), c.get(), d.get());
  return 0;
}

(need improvement)

 

実行例

 78.00,  72.73,  85.00,  72.00
 78.00,  57.00,  72.00,  56.57
 82.00,  83.00,  90.00,  88.00

 

 

References

• htop-osx/ProcessList.c at master · max-horvath/htop-osx