birowo / node-gc-profiler

Allows you to profile when the garbage collector runs, and how long it takes.

node-gc-profiler

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 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
};