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https://github.com/hyj1991/v8-profiler-next
node bindings for the v8 profiler
https://github.com/hyj1991/v8-profiler-next
allocation-profile cpu-profile sampling-heap-profile snapshot v8-profiler
Last synced: 1 day ago
JSON representation
node bindings for the v8 profiler
- Host: GitHub
- URL: https://github.com/hyj1991/v8-profiler-next
- Owner: hyj1991
- License: mit
- Created: 2017-12-25T13:11:49.000Z (almost 7 years ago)
- Default Branch: master
- Last Pushed: 2024-01-10T13:31:51.000Z (11 months ago)
- Last Synced: 2024-10-30T00:33:03.845Z (about 1 month ago)
- Topics: allocation-profile, cpu-profile, sampling-heap-profile, snapshot, v8-profiler
- Language: C++
- Size: 110 KB
- Stars: 218
- Watchers: 4
- Forks: 21
- Open Issues: 4
-
Metadata Files:
- Readme: README.md
- License: LICENSE
Awesome Lists containing this project
- awesome-nodejs - v8-profiler-next - Node bindings for the v8 profiler.  (Repository / Performance Profiling/Analysis)
- awesome-github-star - v8-profiler-next
README
# v8-profiler-next
[](https://www.npmjs.com/package/v8-profiler-next)
[](http://packagequality.com/#?package=v8-profiler-next)
[](https://github.com/hyj1991/v8-profiler-next/actions?query=branch%3Amaster)
[](https://ci.appveyor.com/project/hyj1991/v8-profiler-next)
[](https://www.npmjs.com/package/v8-profiler-next)
[](LICENSE)
## Description
v8-profiler-next provides [node](https://github.com/nodejs/node) bindings for the v8 profiler.
## I. Quick Start
* **Compatibility**
* **node version:** v4.x ~ v21.x
* **platform:** mac, linux, windows
This module can also be used in `worker_threads`.
### take cpu profile
```js
'use strict';
const fs = require('fs');
const v8Profiler = require('v8-profiler-next');
const title = 'good-name';
// set generateType 1 to generate new format for cpuprofile
// to be compatible with cpuprofile parsing in vscode.
v8Profiler.setGenerateType(1);
// ex. 5 mins cpu profile
v8Profiler.startProfiling(title, true);
setTimeout(() => {
const profile = v8Profiler.stopProfiling(title);
profile.export(function (error, result) {
// if it doesn't have the extension .cpuprofile then
// chrome's profiler tool won't like it.
// examine the profile:
// Navigate to chrome://inspect
// Click Open dedicated DevTools for Node
// Select the profiler tab
// Load your file
fs.writeFileSync(`${title}.cpuprofile`, result);
profile.delete();
});
}, 5 * 60 * 1000);
```
Get `.cpuprofile` in `worker_threads`:
```js
'use strict';
const fs = require('fs');
const path = require('path');
const v8Profiler = require('v8-profiler-next');
const workerThreads = require('worker_threads');
v8Profiler.setGenerateType(1);
if (workerThreads.isMainThread) {
const w = new workerThreads.Worker(__filename, {
env: process.env,
});
v8Profiler.startProfiling('main', true);
w.once('exit', code => {
// create cpu profile in main thread
const profile = v8Profiler.stopProfiling('main');
const mainProfile = path.join(__dirname, 'main.cpuprofile');
fs.existsSync(mainProfile) && fs.unlinkSync(mainProfile);
fs.writeFileSync(mainProfile, JSON.stringify(profile));
});
} else {
v8Profiler.startProfiling('worker_threads', true);
// create cpu profile in worker_threads
const start = Date.now();
while (Date.now() - start < 2000) { }
const profile = v8Profiler.stopProfiling('worker_threads');
const workerProfile = path.join(__dirname, 'worker_threads.cpuprofile');
fs.existsSync(workerProfile) && fs.unlinkSync(workerProfile);
fs.writeFileSync(workerProfile, JSON.stringify(profile));
}
```
### take heapsnapshot
```js
'use strict';
const v8Profiler = require('v8-profiler-next');
const snapshot = v8Profiler.takeSnapshot();
// 1. not as stream
snapshot.export(function (error, result) {
if (error){
console.error(error);
return;
}
console.log(result);
snapshot.delete();
});
// 2. as stream
const transform = snapshot.export();
transform.pipe(process.stdout);
transform.on('finish', snapshot.delete.bind(snapshot));
```
Get `.heapsnapshot` in `worker_threads`:
```js
'use strict';
const fs = require('fs');
const path = require('path');
const v8Profiler = require('v8-profiler-next');
const workerThreads = require('worker_threads');
function createSnapshot(filename) {
const snapshot = v8Profiler.takeSnapshot();
const file = path.join(__dirname, filename);
const transform = snapshot.export();
transform.pipe(fs.createWriteStream(file));
transform.on('finish', snapshot.delete.bind(snapshot));
}
if (workerThreads.isMainThread) {
const w = new workerThreads.Worker(__filename, {
env: process.env,
});
// create heapsnapshot in main thread
createSnapshot('main.heapsnapshot');
} else {
const start = Date.now();
const array = [];
while (Date.now() - start < 2000) { array.push(new Array(1e3).fill('*')); }
// create heapsnapshot in worker_threads
createSnapshot('worker_threads.heapsnapshot');
}
```
### take allocation profile
**Attention:** If node version < v12.x, please use sampling heap profiling alone without cpu profiling or taking snapshot.
```js
'use strict';
const v8Profiler = require('v8-profiler-next');
// set a leak array
const arraytest = [];
setInterval(() => {
arraytest.push(new Array(1e2).fill('*').join());
}, 20);
// start 1min sampling profile
v8Profiler.startSamplingHeapProfiling();
setTimeout(() => {
// stop and get allocation profile
const profile = v8Profiler.stopSamplingHeapProfiling();
// upload shf.heapprofile into chrome dev tools -> Memory -> ALLOCATION PRODILES
require('fs').writeFileSync('./shf.heapprofile', JSON.stringify(profile));
console.log(profile);
}, 60 * 1000);
```
Get `.heapprofile` in `worker_threads`:
```js
'use strict';
const fs = require('fs');
const path = require('path');
const v8Profiler = require('v8-profiler-next');
const workerThreads = require('worker_threads');
if (workerThreads.isMainThread) {
const w = new workerThreads.Worker(__filename, {
env: process.env,
});
v8Profiler.startSamplingHeapProfiling();
w.once('exit', code => {
// create heap profile in main thread
const profile = v8Profiler.stopSamplingHeapProfiling();
const mainProfile = path.join(__dirname, 'main.heapprofile');
fs.existsSync(mainProfile) && fs.unlinkSync(mainProfile);
fs.writeFileSync(mainProfile, JSON.stringify(profile));
});
} else {
v8Profiler.startSamplingHeapProfiling();
// create heap profile in worker_threads
const start = Date.now();
const array = [];
while (Date.now() - start < 2000) { array.push(new Array(1e3).fill('*')); }
const profile = v8Profiler.stopSamplingHeapProfiling();
const workerProfile = path.join(__dirname, 'worker_threads.heapprofile');
fs.existsSync(workerProfile) && fs.unlinkSync(workerProfile);
fs.writeFileSync(workerProfile, JSON.stringify(profile));
}
```
## II. License
[MIT License](LICENSE)
Copyright (c) 2018 team of [v8-profiler](https://github.com/node-inspector/v8-profiler), hyj1991