Bug 84897 – WebCore shouldn't call collectAllGarbage directly

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

[Mark Hahnenberg]

Currently, GCController calls Heap::collectAllGarbage directly, which leads to an overload of collections as the timer in GCController and the timer in GCActivityCallback compete for collection time and fire independently. As a result, we end up doing almost 600 full collections during an in-browser run of SunSpider, or 20 full collections on a single load of TechCrunch. 

We can do better by preventing WebCore from calling collectAllGarbage directly and instead going through Heap::reportAbandonedObjectGraph, since that is what WebCore is trying to do--notify the Heap that a lot of garbage may have just been generated when we left a page.

[Mark Hahnenberg]

Created attachment 138891 [details]
Patch

[Mark Hahnenberg]

With this patch, we do 133 GCs in a run of in-browser SunSpider running 20 iterations. We used to do 712 collections using this same testing setup.

We also do 10 collections vs. 20 collections when loading TechCrunch.

[Mark Hahnenberg]

I should also mention that neither our wall clock time nor our benchmark score for in-browser SunSpider are affected by this patch.

[Build Bot]

Comment on attachment 138891 [details]
Patch

Attachment 138891 [details] did not pass win-ews (win):
Output: http://queues.webkit.org/results/12520704

[Mark Hahnenberg]

Created attachment 138899 [details]
Patch

[Geoffrey Garen]

Comment on attachment 138899 [details]
Patch

r=me

[WebKit Review Bot]

Comment on attachment 138899 [details]
Patch

Clearing flags on attachment: 138899

Committed r115288: <http://trac.webkit.org/changeset/115288>

[WebKit Review Bot]

All reviewed patches have been landed.  Closing bug.