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Issue metadata

Status: Untriaged
Owner: ----
Components:
EstimatedDays: ----
NextAction: ----
OS: Linux
Pri: 2
Type: Bug-Regression



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Headless: Page screencast frame rate throttled in M69

Reported by char...@tokbox.com, Sep 12

Issue description

UserAgent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10_13_6) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/68.0.3440.106 Safari/537.36

Steps to reproduce the problem:
1. Launch chrome in headless
2. From chrome-devtools-frontend frontend, navigate anywhere with a high refresh rate -- https://codepen.io/jasonleewilson/details/gPrxwX/ demonstrates this particularly well
3. Observe the screencast

What is the expected behavior?
Behavior of earlier milestones seems to be to draw frames as fast as possible, typically providing significantly better screencast performance than 10 frames per second.

What went wrong?
Page screencasting seems to be throttled to at 10 fps limit.

Did this work before? Yes 67.0.3396.79 Linux

Chrome version: 69.0.3497.92  Channel: beta
OS Version: Ubuntu 16.04.5 LTS
Flash Version: 

Regression reproduces in 70.0.3538.9 dev and 71.0.3549.0 canary, on OS X and Linux.
 
Labels: Needs-Triage-M69
Components: Internals>Headless
Status: Untriaged (was: Unconfirmed)
I see that headless chrome displays the clock very much slower than using chrome.
Components: -Blink
What do the internals stats say? What's the captured vs encoded frame rate? Any cpu overuse etc?
In general, how is the sending client set up?
@sprang Which internals are you interested in?

For reference, I'm still using the URL in the original post:

* Running with the --show-fps-counter switch indicates that the page is rendering at 60 fps.
* CPU usage from the performance tab is minimal; there's not much to do here.
* I haven't quite figured out how to extract tracing data while this is happening, but if it's helpful to you I can follow up with this later today.

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