README
v8-profiler-next
Description
v8-profiler-next provides node bindings for the v8 profiler.
I. Quick Start
- Compatibility
- node version: v4.x ~ v16.x
- platform: mac, linux, windows
take cpu profile
'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);
take heapsnapshot
'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));
take allocation profile
Attention: If node version < v12.x, please use sampling heap profiling alone without cpu profiling or taking snapshot.
'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);
II. License
Copyright (c) 2018 team of v8-profiler, hyj1991