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Issue metadata

Status: Untriaged
Owner: ----
Components:
EstimatedDays: ----
NextAction: ----
OS: Mac
Pri: 3
Type: Bug



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FPS meter inaccurate when painting enabled

Reported by james.th...@gmail.com, Jan 12 2018

Issue description

UserAgent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10_13_2) AppleWebKit/604.4.7 (KHTML, like Gecko) Version/11.0.2 Safari/604.4.7

Steps to reproduce the problem:
1. Enable FPS meter and paint flashing
2. Website will always show nearly 60fps regardless of actual performance of website.

What is the expected behavior?
To see which repaints caused a negative outcome on the FPS.

What went wrong?
The FPS meter always shows nearly 60fps. 

Did this work before? N/A 

Chrome version: <Copy from: 'about:version'>  Channel: stable
OS Version: OS X 10.13.2
Flash Version: 

Issue was reported on stackoverflow years ago but seems to have no fix. From what I can see from my OS (macOS) the paint flashing creates a new process to overlay the boxes which the FPS meter then watches instead of the underlying website. This returns the false positive the website is running at 60 fps when it could be much lower.

https://stackoverflow.com/questions/38908269/why-does-enabling-paint-flashing-substantially-increase-frame-rate
 

Comment 1 by kozy@chromium.org, Jan 17 2018

Owner: alph@chromium.org
Status: Assigned (was: Unconfirmed)

Comment 2 by alph@chromium.org, Jan 17 2018

Components: -Platform>DevTools Internals>GPU
Owner: ----
Status: Untriaged (was: Assigned)

Comment 3 by piman@chromium.org, Jan 19 2018

Components: -Internals>GPU Internals>Compositing
Labels: -Pri-2 Pri-3
Status: Available (was: Untriaged)
Paint flashing is done with impl-side animations, which trigger frames, picked up by the FPS meter, even though the page itself doesn't update (slow commits or raster or whatever).
Project Member

Comment 4 by sheriffbot@chromium.org, Yesterday (46 hours ago)

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

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