695492 - Basic heap profiling tool

Status: RESOLVED DUPLICATE of bug 625846

(Core :: JavaScript Engine, defect)

Description

[Andrew McCreight [:mccr8]]

The only real tools we have right now for determining what is in the heap are the very high level about:memory, which just produces totals for various compartments, and the very fine grained heap dumping tools.  The latter produces output that is too large to get end users to upload, but the former may not give us enough information.  Chrome provides an in-between view called a heap profiler (see http://code.google.com/chrome/devtools/docs/heap-profiling.html ).

The heap profiler has categories like DOMWindow, object, closure, regexp, array, compiled code.  For each of these categories, it provides the number of objects, their "shallow size" and their "retained size".  We have some of this already in about:memory (for instance, the size of regexps and compiled code).

The chrome heap profiler has lots of fancy features like comparing things, and analyzing the heap, but I'm just thinking of some basic census, dumped out in some kind of text format that is easy for bug reporters to grab and upload.