Bug 205366 – [JSC] Memory usage statistics should be attainable without WebCore

• Status: RESOLVED
• Resolution: FIXED
• Component: JavaScriptCore

[Ross Kirsling]

PerformanceLogging::memoryUsageStatistics puts together some very useful information, most of which comes from vm.heap and not from WebCore itself:
https://github.com/WebKit/webkit/blob/master/Source/WebCore/page/PerformanceLogging.cpp#L54-L76

As such it would be nice to have this information available in a JSC-only context.

There are two possible approaches I can see:
1. Add methods to $vm. $vm.globalObjectCount() already exists so we could just add a few more.
2. Add a private C API (say, JSMemoryUsageStatistics under JSBasePrivate.h) which builds a JS object of this information much like the WebCore version.

[Ross Kirsling]

Created attachment 386000 [details]
Patch

[Ross Kirsling]

Here's a patch for the private API approach.

If we feel this is useful enough to warrant a public API (and we're clear on how we'd want the ObjC version to be), I'd be happy to change it accordingly.

[Keith Miller]

Comment on attachment 386000 [details]
Patch

View in context: https://bugs.webkit.org/attachment.cgi?id=386000&action=review

> Source/JavaScriptCore/API/JSBasePrivate.h:54
> +@result An object containing data such as heap size, heap capacity, and object counts.

Can you put an @discussion that describes each of the properties on the returned object.

[Ross Kirsling]

Created attachment 386271 [details]
Patch for landing

[WebKit Commit Bot]

Comment on attachment 386271 [details]
Patch for landing

Clearing flags on attachment: 386271

Committed r253854: <https://trac.webkit.org/changeset/253854>

[WebKit Commit Bot]

All reviewed patches have been landed.  Closing bug.

[Radar WebKit Bug Importer]

<rdar://problem/58128443>