A cross-platform (tested on Linux, Windows, and OSX) profiler for the v8 garbage collector running inside Node.js. It will emit an event after every GC cycle providing you information about the duration and type of cycle.
npm install cavisson-gc-profiler
Example:
var profiler = require('gc-profiler');
profiler.on('gc', function (info) {
console.log(info);
});The info object contains the following properties:
| Property | Type | Description |
|---|---|---|
| date | Date | The approximate start time of the GC cycle. This uses the c++ time library internally, which only has one-second resolution. |
| duration | number | The duration of the GC cycle in milliseconds. |
| type | string | Either Scavenge or MarkSweepCompact depending on the type of GC cycle. |
| forced | boolean | True for a forced cycle. |
| flags | number | The raw GCCallbackFlags provided from v8. |
The profiler.GCCallbackFlags enumeration is provided to help decode the flags property.
profiler.GCCallbackFlags = {
kNoGCCallbackFlags: 0,
kGCCallbackFlagCompacted: 1 << 0, // this flag is never set in v8 versions >= 3.6.5
kGCCallbackFlagConstructRetainedObjectInfos: 1 << 1,
kGCCallbackFlagForced: 1 << 2
};