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danielkhan/cpuprofiler.js

Created October 18, 2015 10:01
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  1. danielkhan created this gist Oct 18, 2015.
    52 changes: 52 additions & 0 deletions cpuprofiler.js
    View file
    Original file line number Diff line number Diff line change
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    /**
    * Simple userland CPU profiler using v8-profiler
    * Usage: require('[path_to]/CpuProfiler').init('datadir')
    *
    * @module CpuProfiler
    * @type {exports}
    */

    var fs = require('fs');
    var profiler = require('v8-profiler');
    var _datadir = null;

    /**
    * Init and schedule profiler runs
    *
    * @param datadir Folder to save the data to
    */
    module.exports.init = function (datadir) {
    _datadir = datadir;
    setInterval(startProfiling, 30 * 1000);
    };

    /**
    * Starts profiling and schedules its end
    */
    function startProfiling() {
    var stamp = Date.now();
    var id = 'profile-' + stamp;

    // Use stdout directly to bypass eventloop
    fs.writeSync(1, 'Start profiler with Id [' + id + ']\n');

    // Start profiling
    profiler.startProfiling(id);


    // Schedule stop of profiling in x seconds
    setTimeout(function () {
    stopProfiling(id)
    }, 5000);
    }

    /**
    * Stops the profiler and writes the data to a file
    * @param id the id of the profiler process to stop
    */
    function stopProfiling(id) {
    var profile = profiler.stopProfiling(id);
    fs.writeFile(_datadir + '/' + id + '.cpuprofile', JSON.stringify(profile), function () {
    console.log('Profiler data written');
    });
    }