Bug 101782
| Summary: | [v8?] 37% SunSpider regression | ||
|---|---|---|---|
| Product: | WebKit | Reporter: | Ojan Vafai <ojan> |
| Component: | Tools / Tests | Assignee: | Nobody <webkit-unassigned> |
| Status: | RESOLVED WONTFIX | ||
| Severity: | Normal | CC: | abarth, andersca, dglazkov, esprehn, ggaren, haraken, morrita, shinyak |
| Priority: | P2 | Keywords: | PerfRegression |
| Version: | 528+ (Nightly build) | ||
| Hardware: | Unspecified | ||
| OS: | Unspecified | ||
Ojan Vafai
It shows in some of the other sunspider tests as well, but here are the most clear graphs.
http://build.chromium.org/f/chromium/perf/chromium-rel-win7-webkit/sunspider/report.html?rev=166898&graph=math-spectral-norm&trace=t&history=150
http://build.chromium.org/f/chromium/perf/chromium-rel-win7-webkit/sunspider/report.html?rev=166898&graph=access-fannkuch&trace=t&history=150
http://build.chromium.org/f/chromium/perf/chromium-rel-win7-webkit/sunspider/report.html?rev=166898&graph=bitops-3bit-bits-in-byte&trace=t&history=150
It's clearly not a chromium side change. Chromium regression range: http://build.chromium.org/f/chromium/perf/dashboard/ui/changelog.html?url=/trunk/src&mode=html&range=166683:166688
WebKit regression range: http://trac.webkit.org/log/?verbose=on&rev=133904&stop_rev=133902
Looks pretty clearly to be http://trac.webkit.org/changeset/133904/, since we got the equivalent performance gain when http://trac.webkit.org/changeset/133429/ was committed.
It would be good to understand what http://trac.webkit.org/changeset/133429/ does better so we can understand:
a) Why it makes sunspider so much faster.
b) Why it made the other tests slower and use more memory.
| Attachments | ||
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| Add attachment proposed patch, testcase, etc. |
Ojan Vafai
This is also probably V8 only, but I don't have an easy way to verify that.
Ojan Vafai
Also a 7% *improvement* on dom_perf CreateNodes: http://build.chromium.org/f/chromium/perf/linux-release-webkit-latest/dom_perf/report.html?rev=166857&graph=CreateNodes&trace=score&history=150
And a 20% regression on dom_perf GetElements:
http://build.chromium.org/f/chromium/perf/mac-release-10.6-webkit-latest/dom_perf/report.html?rev=166869&graph=Get%20Elements&trace=score&history=150
Adam Barth
Huh? I don't understand how http://trac.webkit.org/changeset/133429/ could have affected SunSpider.
Ojan Vafai
Yeah, if you look at when the patch was landed and reverted though, it's clearly this revision. I think the v8 properties we're changing must have an effect we don't understand?
Adam Barth
Maybe the feature itself slows down sunspider and that patch just happened to turn it off?
Dimitri Glazkov (Google)
wat. This makes no sense :-\
Ojan Vafai
To be clear, these tests take ~2ms to run, so a 30% regression is relatively small. We should considering changing our sunspider harness on these bots to do runs/second so we can get more useful numbers.
I think someone needs to take a look at what the IDL changes affect in terms of the code generator output to make sense of this. Just a guess though.
Kentaro Hara
(In reply to comment #7)
> I think someone needs to take a look at what the IDL changes affect in terms of the code generator output to make sense of this. Just a guess though.
The IDL change just changed DOM attributes that have [Conditional=SHADOW_DOM]. So at the very least, it will affect behaviors where SHADOW_DOM is enabled. On the other hand, SunSpider is not yet using SHADOW_DOM, right?
Hajime Morrita
(In reply to comment #8)
> (In reply to comment #7)
> > I think someone needs to take a look at what the IDL changes affect in terms of the code generator output to make sense of this. Just a guess though.
>
> The IDL change just changed DOM attributes that have [Conditional=SHADOW_DOM]. So at the very least, it will affect behaviors where SHADOW_DOM is enabled. On the other hand, SunSpider is not yet using SHADOW_DOM, right?
Anders Carlsson
V8 is gone.