[Nodejs] - Compare library of cpu utils for nodejs

CPU Time

CPU time (or process time) is the amount of time for which a central processing unit (CPU) was used for processing instructions of a computer program or operating system, as opposed to elapsed time, which includes for example, waiting for input/output (I/O) operations or entering low-power (idle) mode. The CPU time is measured in clock ticks or seconds. Often, it is useful to measure CPU time as a percentage of the CPU's capacity

Library

Built-in

os.cpus()

os-utils

https://github.com/oscmejia/os-utils

Example

var os     = require('os-utils');
os.cpuUsage(function(v){
    console.log( 'CPU Usage (%): ' + v );
});
os.cpuFree(function(v){
    console.log( 'CPU Free:' + v );
});

exports.cpuUsage = function(callback){
    getCPUUsage(callback, false);
}

function getCPUUsage(callback, free){

    var stats1 = getCPUInfo();
    var startIdle = stats1.idle;
    var startTotal = stats1.total;

    setTimeout(function() {
        var stats2 = getCPUInfo();
        var endIdle = stats2.idle;
        var endTotal = stats2.total;

        var idle     = endIdle - startIdle;
        var total     = endTotal - startTotal;
        var perc    = idle / total;

        if(free === true)
            callback( perc );
        else
            callback( (1 - perc) );

    }, 1000 );
    // 1초 동안 사용된 cpu idle 값
}

function getCPUInfo(callback){
    var cpus = _os.cpus();

    var user = 0;
    var nice = 0;
    var sys = 0;
    var idle = 0; // A computer processor is described as idle when it is not being used by any program.
    var irq = 0;
    var total = 0;

    for(var cpu in cpus){
        if (!cpus.hasOwnProperty(cpu)) continue;
        user += cpus[cpu].times.user;
        nice += cpus[cpu].times.nice;
        sys += cpus[cpu].times.sys;
        irq += cpus[cpu].times.irq;
        idle += cpus[cpu].times.idle;
    }

    var total = user + nice + sys + idle + irq;

    return {
        'idle': idle,
        'total': total
    };
}

Times

an object containing the number of CPU ticks spent in: user, nice, sys, idle, and irq

https://nodejs.org/docs/latest/api/os.html#os_os_cpus

Get average load

os.loadavg(1)
os.loadavg(5)
os.loadavg(15)

Node-os-utils

https://github.com/SunilWang/node-os-utils

CPU average usage

• [interval]: number - interval millisecond. defaulta: 1000

usage: function (interval) {
    var self = this

    if (!interval) {
      interval = bucket.options.INTERVAL
    }

    return new Promise(function (resolve) {
      if (typeof interval !== 'number') {
        throw new TypeError('interval must be a number!')
      }

      var startMeasure = self.average()

      setTimeout(function () {
        var endMeasure = self.average()
        var idleDifference = endMeasure.avgIdle - startMeasure.avgIdle
        var totalDifference = endMeasure.avgTotal - startMeasure.avgTotal
        var cpuPercentage = (10000 - Math.round(10000 * idleDifference / totalDifference)) / 100

        return resolve(cpuPercentage)
      }, interval)
    })
},

• support interval range
• interval is millsecond
  • get cpuUsage during interval millisecond default interval is 1second

Example

export class CpuUtil {
  private static cpuUsageObservable = new Observable<number>(this.sendCpuUsageEvent);
  static sendCpuUsageEvent(subscriber: Subscriber<number>) {
    const CPU_USAGE_INTERVAL = 1000;
    const CPU_USAGE_EVENT_INTERVAL = 1000;

    setInterval(async () => {
      const cpuUsage = await osu.cpu.usage(CPU_USAGE_INTERVAL)
      subscriber.next(cpuUsage);
    }, CPU_USAGE_EVENT_INTERVAL);
  }

  static subscribe(callback: (value: number) => void) {
    this.cpuUsageObservable.subscribe(callback);
  }
}

CpuUtil.subscribe((value) => {
  console.log('1', value);
});

CpuUtil.subscribe((value) => {
  console.log('2', value);
});

output

const temp = () => {
  return new Promise((resolve, reject) => {
    setTimeout(() => {
      resolve('asdf');
    }, 1000);
  });
};

setInterval(async () => {
  const data = await temp();
  console.log(data);
}, 1000);

Reference

• https://stackoverflow.com/questions/36816181/get-view-memory-cpu-usage-via-nodejs
• https://stackoverflow.com/questions/9565912/convert-the-output-of-os-cpus-in-node-js-to-percentage