Bug 15865

Summary: Store .lut.h hashfile keys as UTF16 stings for faster key compares
Product: WebKit Reporter: Eric Seidel (no email) <eric>
Component: JavaScriptCoreAssignee: Nobody <webkit-unassigned>
Status: RESOLVED INVALID    
Severity: Normal CC: emacemac7
Priority: P2    
Version: 528+ (Nightly build)   
Hardware: Mac   
OS: OS X 10.4   
Attachments:
Description Flags
the fix
none
naive fix (0.5% slower according to SunSpider) none

Eric Seidel (no email)
Reported 2007-11-06 20:01:03 PST
Store .lut.h hashfile keys as UTF16 stings for faster key compares I've attached a patch which does that, I've not yet perf tested it. (About to do so.)
Attachments
the fix (4.50 KB, patch)
2007-11-06 20:01 PST, Eric Seidel (no email) 		no flags
DetailsFormatted DiffDiff
naive fix (0.5% slower according to SunSpider) (5.67 KB, patch)
2007-11-06 20:40 PST, Eric Seidel (no email) 		no flags
DetailsFormatted DiffDiff
Show Obsolete (1) View All Add attachment proposed patch, testcase, etc.
Eric Seidel (no email)
Comment 1 2007-11-06 20:01:48 PST
Created attachment 17077 [details] the fix
Eric Seidel (no email)
Comment 2 2007-11-06 20:40:06 PST
Created attachment 17079 [details] naive fix (0.5% slower according to SunSpider)
Eric Seidel (no email)
Comment 3 2007-11-06 21:02:37 PST
Hum.. well, the shark diff makes no sense at all. spectral-norm: 2.2% *slower* 126.8ms +/- 0.8% 129.6ms +/- 0.9% significant is the worst regression. four others are more than 1.0% slower. Overall 0.2% slower according to my most recent run.
Eric Seidel (no email)
Comment 4 2007-11-08 13:16:38 PST
A good test to try and optimize this with might be string-validate-input.js. I see that test spending 2.4% of total time in findEntry()
Darin Adler
Comment 5 2008-04-02 02:29:48 PDT
I did a fancier version of this optimization recently. I think this bug is probably obsolete.
Alexey Proskuryakov
Comment 6 2009-03-24 10:57:45 PDT
Eric, is this bug still valid?
Eric Seidel (no email)
Comment 7 2009-03-24 11:29:24 PDT
Yeah, I think we tried this and it was slower.
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