tmux-mem-cpu-load/openbsd/cpu.cc

/*
 * Copyright 2012 Matthew McCormick
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 * */
// This file was Authored by Justin Crawford <Justasic@gmail.com>
// Based on: github.com/freebsd/freebsd/blob/master/usr.bin/top/machine.c
// Based on: Apple.cpp for load_string/mem_string and apple's documentation

#include <sys/types.h>
#include <unistd.h> // usleep

#include <sys/sysctl.h>
#include <sys/types.h>

#include "error.h"
#include "cpu.h"

uint8_t get_cpu_count() 
{
  int cpu_count = 1; // default to 1
  int mib[2] = { CTL_HW, HW_NCPU };
  size_t len = sizeof( cpu_count );

  if(sysctl(mib, 2, &cpu_count, &len, NULL, 0) < 0)
  {
	error("sysctl: error getting cpu count");
  }

  return cpu_count;
}

float cpu_percentage( unsigned int cpu_usage_delay )
{
  int cpu_ctl[] = { CTL_KERN, KERN_CPTIME };

  int32_t load1[CPUSTATES];
  int32_t load2[CPUSTATES];

  size_t size = sizeof( load1 );

  // get cpu times
  if(sysctl(cpu_ctl, 2, &load1, &size, NULL, 0) < 0)
  {
	error("sysctl: error getting cpu stats");
  }

  usleep(cpu_usage_delay);

  // update cpu times
  if(sysctl(cpu_ctl, 2, &load2, &size, NULL, 0) < 0)
  {
	error("sysctl: error getting cpu stats");
  }

  // Current load times
  unsigned long long current_user = load1[CP_USER];
  unsigned long long current_system = load1[CP_SYS];
  unsigned long long current_nice = load1[CP_NICE];
  unsigned long long current_idle = load1[CP_IDLE];
  // Next load times
  unsigned long long next_user = load2[CP_USER];
  unsigned long long next_system = load2[CP_SYS];
  unsigned long long next_nice = load2[CP_NICE];
  unsigned long long next_idle = load2[CP_IDLE];
  // Difference between the two
  unsigned long long diff_user = next_user - current_user;
  unsigned long long diff_system = next_system - current_system;
  unsigned long long diff_nice = next_nice - current_nice;
  unsigned long long diff_idle = next_idle - current_idle;

  return static_cast<float>(diff_user + diff_system + diff_nice) /
	static_cast<float>(diff_user + diff_system + diff_nice + diff_idle) *
	100.0;
}