Bug 90255

Summary: JSObject wastes too much memory on unused property slots
Product: WebKit Reporter: Filip Pizlo <fpizlo>
Component: JavaScriptCoreAssignee: Filip Pizlo <fpizlo>
Status: RESOLVED FIXED    
Severity: Normal CC: zan
Priority: P2    
Version: 528+ (Nightly build)   
Hardware: All   
OS: All   
Bug Depends on: 90336    
Bug Blocks:    
Attachments:
Description Flags
the patch
fpizlo: review-
the patch mhahnenberg: review+

Filip Pizlo
Reported 2012-06-29 00:43:12 PDT
1) Non-final objects should not have inline property storage, since it is used rarely and allocating out-of-line storage is cheap. 2) The initial size of out-of-line storage should not be a whopping 16 slots, or 128 bytes. It should be some sensible amount, like maybe 4 (32 bytes), or 2x the inline storage, whichever is bigger.
Attachments
the patch (20.00 KB, patch)
2012-06-29 00:49 PDT, Filip Pizlo 		fpizlo: review-
DetailsFormatted DiffDiff
the patch (26.84 KB, patch)
2012-06-29 17:07 PDT, Filip Pizlo 		mhahnenberg: review+
DetailsFormatted DiffDiff
Show Obsolete (1) View All Add attachment proposed patch, testcase, etc.
Filip Pizlo
Comment 1 2012-06-29 00:49:18 PDT
Created attachment 150108 [details] the patch
Mark Hahnenberg
Comment 2 2012-06-29 08:48:57 PDT
Comment on attachment 150108 [details] the patch View in context: https://bugs.webkit.org/attachment.cgi?id=150108&action=review Overall, looks good. r=me with suggestions :-) > Source/JavaScriptCore/runtime/JSObject.h:351 > +#if JSNonFinalObject_inlineStorageCapacity I guess this is to make it easier if we want to change back to non-zero inline storage for JSNonFinalObjects in the future? > Source/JavaScriptCore/runtime/JSObject.h:361 > + globalData, structure, Why on a separate line? > Source/JavaScriptCore/runtime/JSObject.h:574 > + if (propertyStorageCapacity() == inlineStorageCapacity()) You could assert that propertyStorageCapacity() >= inlineStorageCapacity() at the beginning of the function and then return propertyStorageCapacity() == inlineStorageCapacity(). Two less lines!
Filip Pizlo
Comment 3 2012-06-29 17:07:00 PDT
Comment on attachment 150108 [details] the patch Found some bugs. New patch on the way.
Filip Pizlo
Comment 4 2012-06-29 17:07:17 PDT
Created attachment 150276 [details] the patch
Mark Hahnenberg
Comment 5 2012-06-29 17:23:15 PDT
Comment on attachment 150276 [details] the patch r=me
Filip Pizlo
Comment 6 2012-06-29 17:25:27 PDT
Landed in http://trac.webkit.org/changeset/121605
Zan Dobersek
Comment 7 2012-06-30 04:45:32 PDT
Re-opened since this is blocked by 90336
Filip Pizlo
Comment 8 2012-06-30 20:55:42 PDT
Relanded with fixes in http://trac.webkit.org/changeset/121633.
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