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Issue metadata

Status: WontFix
Owner: ----
Closed: May 2018
Cc:
Components:
EstimatedDays: ----
NextAction: ----
OS: Mac
Pri: 3
Type: Bug-Regression



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tough_webgl_cases mean_frame_times got very noisy around 9/3/2016

Project Member Reported by kbr@chromium.org, Oct 19 2016

Issue description

vmiura@ pointed out that the mean_frame_times of the tough_webgl_cases performance tests got very noisy around September 3, 2016:
https://chromeperf.appspot.com/report?sid=220fc7bd7a1074610c4caeb6960600ef162ee330cdff793edbbb3b55b0dd99c6&start_rev=415037&end_rev=426150

It's not clear what may have caused this. This regression list seems to be conservative:
http://test-results.appspot.com/revision_range?start=415884&end=416454

and it contains no changes that are obviously relevant. vmiura@ suggested perhaps throttling changes by ericrk@ and ccameron@, but this blamelist doesn't contain them. There are a few V8 rolls, which I haven't dug into, but suspect they would not be the cause.

The same issue doesn't seem to show up on other platforms, i.e., Windows:
https://chromeperf.appspot.com/report?sid=bdde1fe421bcd5434ec9e48f4869d12fe58e45e3970e17923c4cb173a61681ad

Does anyone have an idea about what might have changed? The affected tests are pretty simple and don't do much CPU or GPU work.

 

Comment 1 by kbr@chromium.org, Oct 19 2016

Cc: vmi...@chromium.org
Cc: -eisinger@chromium.org jochen@chromium.org
2 V8 rolls:
- https://chromium.googlesource.com/v8/v8/+log/31399854..3fd3ba53
- https://chromium.googlesource.com/v8/v8/+log/0e51f51f..31399854

Only interesting (don't know if the benchmark makes use of DataView_s) CL:
- https://chromium.googlesource.com/v8/v8/+/97f6266f564e0b8a6f8ecd2f12cfadfccccff511: [turbofan] Migrate remaining DataView builtins to C++.

Comment 3 by kbr@chromium.org, Oct 19 2016

None of the benchmarks should be using DataView.

Thanks for taking a look mlippautz@.

Sorry, I missed a couple of v8 rolls due to the paged rev list.

There is one more interesting commit:
https://chromium.googlesource.com/v8/v8/+/ce66eec800e7329b0967b0f8eec7db05b2b22218: [heap] Introduce hard limit for external memory

We the incremental marking phase of V8 earlier (64M), but move hard limit for doing a full GC 
to half of the V8 heap size (700M on 64bit). Previously we would start GCing incrementally at ~200M and not make any progress (which actually is buggy behavior). Can we do a bisect?

Comment 5 by kbr@chromium.org, Oct 19 2016

Kicked off a bisect between revisions 415828 and 416464.

Comment 6 by jochen@chromium.org, Oct 20 2016

Cc: jkummerow@chromium.org
Status: Available (was: Untriaged)
Labels: -Performance Performance-Loading
Project Member

Comment 9 by sheriffbot@chromium.org, May 2 2018

Labels: Hotlist-Recharge-Cold
Status: Untriaged (was: Available)
This issue has been Available for over a year. If it's no longer important or seems unlikely to be fixed, please consider closing it out. If it is important, please re-triage the issue.

Sorry for the inconvenience if the bug really should have been left as Available.

For more details visit https://www.chromium.org/issue-tracking/autotriage - Your friendly Sheriffbot

Comment 10 by kbr@chromium.org, May 2 2018

Status: WontFix (was: Untriaged)
These seem to have settled down by themselves. There have been tons of changes since this bug was reported.

https://chromeperf.appspot.com/report?sid=a84d11874fff64121609f33cc88622062606f12df602364f1250b3432c9c9143

Screen Shot 2018-05-02 at 2.40.45 PM.png
252 KB View Download

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