Bug 21633

Summary:

Avoid using a HashMap when there is only a single transition

Product:

WebKit

Reporter:

Cameron Zwarich (cpst) <zwarich>

Component:

JavaScriptCore

Assignee:

Cameron Zwarich (cpst) <zwarich>

Status:

RESOLVED FIXED

Severity:

Normal

Priority:

Version:

528+ (Nightly build)

Hardware:

All

OS:

All

Bug Depends on:

Bug Blocks:

21513

Attachments:

Description	Flags
Proposed patch	mjs: review+

Cameron Zwarich (cpst)

Reported 2008-10-15 17:43:52 PDT

We have determined through testing that the vast majority of StructureIDs have only 0 or 1 transition. We should not create a whole HashMap in these cases.

Attachments
Proposed patch (5.60 KB, patch) 2008-10-15 19:10 PDT, Cameron Zwarich (cpst)	mjs: review+	Details Formatted Diff Diff
View All Add attachment proposed patch, testcase, etc.

Cameron Zwarich (cpst)

Comment 1 2008-10-15 19:10:55 PDT

Created attachment 24382 [details] Proposed patch It would be nice if someone else (Maciej?) ran benchmarks on his own machine to verify.

Maciej Stachowiak

Comment 2 2008-10-15 20:46:42 PDT

Comment on attachment 24382 [details] Proposed patch r=me But it would be nice if we could abstract away the single-transition optimization a bit, by having some helper functions that hide the core logic (e.g. one to get an existing transition for a property - it could check either the single entry or the hashtable as appropriate) etc.

Cameron Zwarich (cpst)

Comment 3 2008-10-15 21:38:07 PDT

Landed in r37627.

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