High CPU usage

[asolopovas]

Hi,
Grunt Watch consumes about 65-70% CPU Resources.

my devDependencies are as follows.

  "devDependencies": {
    "grunt": "^0.4.5",
    "grunt-contrib-uglify": "^0.9.1",
    "grunt-contrib-watch": "^0.6.1",
    "grunt-sass": "^0.18.1",
    "load-grunt-tasks": "^3.1.0",
    "node-bourbon": "^4.2.1-beta1"
  }

my gruntfile:

var path = "C:/gdrive/apps/3oak/wp-content/themes/3flooring/";
module.exports = function(grunt) {
    require('load-grunt-tasks')(grunt); // npm install --save-dev load-grunt-tasks
    grunt.initConfig({
        pkg: grunt.file.readJSON('package.json'),
        // Watch ===========
        watch: {
            // Sass -----
            sass: {
                files: [
                    path + 'components/sass/*.{scss,sass}',
                    path + 'components/sass/styles/*.{scss,sass}',
                    path + 'components/sass/styles/custom/*.{scss,sass}',
                    path + 'components/sass/styles/custom/**/*.{scss,sass}'
                    ],
                tasks: ['sass']
            },
            // Reload -
            livereload: {
                files: [
                    path + '*.php',
                    path + '**/*.php',
                    path + '**/**/*.php',
                    path + 'js/*.{js,json}',
                    path + 'js/**/*.{js,json}',
                    path + 'components/sass/*.{scss,sass}',
                    path + 'components/sass/**/*.{scss,sass}',
                    path + 'components/sass/**/**/*.{scss,sass}'],
                options: {
                    livereload: true
                }
            },
            // Scripts -
            scripts: {
                files: [
                    path + 'components/js/*.{js,json}'
                    ],
                tasks: ['uglify']
            }, // scripts
        },
        sass: {
            dist: {
                options: {
                    sourceMap: true,
                    includePaths: [
                        require('node-bourbon').includePaths,
                        path + 'components/sass/*.{scss,sass}',
                        path + 'components/sass/**/*.{scss,sass}'
                    ],
                    outputStyle: 'nested',
                    lineNumbers: true,
                },
                files: [
                    {src: path + 'components/sass/style.scss', dest: path + 'style.css'}
                ],
            }
        },
        // Uglify 
        uglify: {
            my_target: {
                options: {
                    sourceMap: true,
                    sourceMapName: path + 'scripts.min.map'
                },
                files: [
                    {src: path + 'components/js/*.js', dest: path + 'js/scripts.min.js'}
                ],
            }
        }
    });
    grunt.loadNpmTasks('grunt-contrib-uglify');
    grunt.loadNpmTasks('grunt-contrib-watch');
    grunt.registerTask('default', 'watch');
};

[acollard]

Same problem here. CPU stays at 50% on my i7 3770. Running on Windows 7.

We are probably watching between 500-1000 files.

[Stratus3D]

I am also experiencing this issue on OSX 10.10.4 with grunt v0.4.5 and grunt-contrib-watch 0.6.1.

There are several other issues that seem to be related but apparently the underlying problem has not been fixed:
#35
#145

I tried everything mentioned in those issues and nothing helped. Grunt is always using about 70% of my CPU and fseventsd is using about 15%.

[kiril-chilingarashvili]

Have to work on few projects (4-5) with grunts running in parallel, CPU usage in total is around 100% all the time ..
single process is watching about 2000 files, and CPU goes up to 20-25 %
And that is when I don't change files.
If I comment out watch task, and leave only express running, CPU goes down to 2%
Machine: SSD stripe 240GB, i7 quad cores, 16 GB RAM

[yang]

I'm also seeing the same issue on OS X 10.10 with node 4.1.0 and grunt-contrib-watch 0.6.1.

[rogeraleite]

Same issue here, but watching just 10 files. Grunt is using 100% of the CPU.

[partnuz]

Have you tried this

options: { interval: 1000 },

[yang]

That increases the latency and hurts the instantly responsive illusion.

[netzbandit]

I have the same issue with grunt 0.4.5 and grunt-watch 0.6.1 on OSX 10.10.5
Even with the interval option the CPU usage jumps to 100% as soon as I edit a file. And I have only about 10 files to watch!

[msierks]

@partnuz: this worked for me

[eddyerburgh]

Same problem with grunt 0.4.5 and grunt-watch 0.6.1 windows 7, watching 12 files, 100% CPU usage when editing files

[HugoHeneault]

options: { interval: 1000 },

hurts the instantly responsive illusion, but using a lower number, as 300, reduced my CPU usage from 50% to 3-10%...

Good workaround until we figure something else.

[callmevlad]

Switching to https://github.com/JimRobs/grunt-chokidar (forked off of grunt-contrib-watch but uses chokidar instead of gaze for file system watching) drops my CPU usage from ~25% to somewhere near 0% with the same functionality.

@shama @tkellen Would you consider a pull request to switch the underlying lib from gaze to chokidar?

[vladikoff]

@callmevlad see #314

[callmevlad]

@vladikoff Thanks for the link! That issue is from a few years ago, and seems to make claims about Gaze >= 0.6 that don't seem to be true today at 1.0.0 (like not using native OS events instead of polling, for example), so I was hoping that decision would be revisited.

It would be great to get @shama's thoughts around which changes in jimmy-robert@a0f15e7 are incompatible two years later, or at least start a discussion around why gaze must take up so much CPU as the number of watched files grows.

[shama]

@callmevlad gaze@0.6 experimented with going fully to native events. It was certainly faster and consumed far less CPU but it caused a lot of issues. One issue is building the native addon can be challenging for users, especially on Windows. So 1.0.0 is basically an updated 0.5, tabling going full native for now.

I'm not against revisiting chokidar though. It's been awhile since I've evaluated implementing it here. AFAIK, chokidar requires the native addon fsevents to be built on OSX (which isn't too bad) and just uses fs.watch for other platforms. If chokidar is actually passing all the tests here as a drop in replacement for gaze, then they've certainly came a long way and I'd be really open to consider it.