https://github.com/vweevers/gctime

Record time spent on GC in high resolution.
https://github.com/vweevers/gctime

garbage-collection gc nodejs nodejs-addon npm-package prebuilt-binaries

Last synced: 2 months ago
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Record time spent on GC in high resolution.

• Host: GitHub
• URL: https://github.com/vweevers/gctime
• Owner: vweevers
• License: mit
• Created: 2018-09-10T21:00:02.000Z (over 6 years ago)
• Default Branch: master
• Last Pushed: 2020-12-11T17:46:07.000Z (over 4 years ago)
• Last Synced: 2025-03-28T21:39:05.671Z (2 months ago)
• Topics: garbage-collection, gc, nodejs, nodejs-addon, npm-package, prebuilt-binaries
• Language: JavaScript
• Size: 4.88 KB
• Stars: 1
• Watchers: 1
• Forks: 0
• Open Issues: 0
• Metadata Files:
  • Readme: readme.md
  • License: LICENSE

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README

        
# gctime

> **Record time spent on GC in high resolution.**  

> Yields a statistic set with `min`, `max` and `sum` of duration and `size` (number of cycles).

[![npm status](http://img.shields.io/npm/v/gctime.svg)](https://www.npmjs.org/package/gctime)

[![node](https://img.shields.io/node/v/gctime.svg)](https://www.npmjs.org/package/gctime)

[![Travis build status](https://img.shields.io/travis/vweevers/gctime.svg?label=travis)](http://travis-ci.org/vweevers/gctime)

[![AppVeyor build status](https://img.shields.io/appveyor/ci/vweevers/gctime.svg?label=appveyor)](https://ci.appveyor.com/project/vweevers/gctime)

[![JavaScript Style Guide](https://img.shields.io/badge/code_style-standard-brightgreen.svg)](https://standardjs.com)

[![Dependency status](https://img.shields.io/david/vweevers/gctime.svg)](https://david-dm.org/vweevers/gctime)

## Usage

Continuously log GC cycles and duration:

```js

const gctime = require('gctime')

const nano = require('nanoseconds')

const diffy = require('diffy')()

const fmt = require('util').format

const stats = gctime.get()

diffy.render(function () {

  // Update stats. Alternatively call .get() to get a new object.

  gctime.accumulate(stats)

  return fmt(

    'cycles: %d. min: %dns. max: %dns. avg: %dns',

    stats.size,

    nano(stats.min),

    nano(stats.max),

    nano(stats.sum) / stats.size | 0

  )

})

gctime.start()

setInterval(() => Array(1e6).fill(1), 100)

setInterval(() => diffy.render(), 500)

```

```

$ node example.js

cycles: 174. min: 45488ns. max: 843813ns. avg: 131384ns

```

When you're done, call `gctime.stop()`. For a single run, you can skip `get()` as `stop()` returns stats too: `stats = gctime.stop()`.

The statistics follow the format of [`process.hrtime()`](https://nodejs.org/api/process.html#process_process_hrtime_time): an array of `[seconds, nanoseconds]` where `nanoseconds` is the remaining part of the time that can't be represented in second precision.

The state of `start()`, `get()` and `stop()` is global. They throw if already started or stopped, respectively.

## Install

With [npm](https://npmjs.org) do:

```

npm install gctime

```

## License

[MIT](LICENSE) © 2017-present Vincent Weevers. Contains 8 lines of code from Node.js [© many people](https://github.com/nodejs/node/blob/master/LICENSE).