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Issue 712344 link

Starred by 3 users

Issue metadata

Status: WontFix
Owner:
Closed: Jan 2018
Cc:
Components:
EstimatedDays: ----
NextAction: ----
OS: Mac
Pri: 2
Type: Bug


Participants' hotlists:
TaskThrottling


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Renderer CPU usage doesn't drop for hidden full screen windows.

Project Member Reported by sdy@chromium.org, Apr 17 2017

Issue description

Chrome Version: 60.0.3073.0
OS: macOS 10.12.4

What steps will reproduce the problem?
(1) Open a web page that does a lot of drawing (e.g. http://listen.hatnote.com/).
(2) Send the window to another space, or miniaturize it to the Dock.
(3) Bring it back, then make it full screen and switch to another space (so that it's no longer visible).

What is the expected result?
Check the page's CPU usage with the Chrome Task Manager after each step. Its CPU usage should drop dramatically when it's not visible.

What happens instead?
CPU usage drops at step (2), but not at step (3).
 
full_screen_hidden_still_using_cpu.mp4
3.9 MB View Download
Cc: ojan@chromium.org altimin@chromium.org skyos...@chromium.org
For this particular page the problem is that it is playing audio and therefore not throttled.

Comment 3 by sdy@chromium.org, Apr 21 2017

Re. #2, minimizing the window, sending it to another desktop, or switching tabs all result in a significant drop in CPU usage. I assumed this was just a bug with full screen on Mac not setting the tab to hidden and stopping some of the rendering/compositing machinery.
Re #3: Yes, you're probably right. I wonder if there is a repro without any sound played? It'll be easier to work with.

Comment 5 by sdy@chromium.org, Apr 28 2017

Sure thing, this URI also works with the original steps:

    data:text/html,<p id=count></p><script>setInterval(() => { count.textContent = +new Date(); }, 10);</script>
Labels: Needs-Investigation
Owner: altimin@chromium.org
Status: Assigned (was: Untriaged)
altimin - mind taking this?
Owner: ----
It seems that the problem is with appropriate visibility signals not being plumbed to scheduler (and blink). I'm not the best person to deal with this and I have my hands full at the moment.

benhenry@, could you find someone from Chrome for Mac team to look into this?
Status: Available (was: Assigned)

Comment 10 by sdy@chromium.org, May 19 2017

Owner: sdy@chromium.org
Status: Assigned (was: Available)
I can own this, but feel free to take it.

Comment 11 by sdy@chromium.org, Jan 26 2018

Status: WontFix (was: Assigned)
It looks like this was fixed by macOS 10.13, so I'm suspecting an issue with occlusion reporting in older OSs.

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