NAME

js_objgc.d - trace JavaScript Object GC using DTrace.

SYNOPSIS

js_objgc.d

DESCRIPTION

This traces JavaScript activity from all running browers on the system which support the JavaScript DTrace provider.

This script provides information on which objects are not being garbage collected, an issue which causes the browser to steadily leak memory. We trace object creation (+1) and destruction (-1), and provide a summary each second of the running tally of the object class and originating filename. If over the period of several minutes an object type is still steadily increasing, then that would be of interest. Be patient, depending on the rate of object creation it can take over ten minutes for garbage collect to kick in.

OS

Any

STABILITY

Evolving - uses the DTrace JavaScript provider, which may change as additional features are introduced. Check JavaScript/Readme to see what version these scripts are based on.

EXAMPLES

Default output,: # js_objgc.d

FIELDS

FILE: Filename that contained the function
CLASS: Class to which this new object belongs
TOTAL: Object entropy (positive == uncollected)

NOTES

- it is possible that you will see negative entropy. That happens when you begin tracing after some objects have already been created, and then trace their destruction. - there are other Things that GC handles, other than Objects; extra probes can be added to trace them, should the need arise.

DOCUMENTATION

See the DTraceToolkit for further documentation under the Examples, Notes and Docs directories. The example files may be especially useful as they aim to demonstrate how to interpret the output.

EXIT

js_objgc.d will run until Ctrl-C is hit.

AUTHOR

Brendan Gregg [CA, USA]