1969771 - WebGLRenderCapability FPP/RFP target limits frame rate to 60FPS for certain content (ex. www.vsynctester.com)

Status: UNCONFIRMED

(Core :: Privacy: Anti-Tracking, defect, P3)

Description

[celenity [:celenity]]

On Linux (GNOME Wayland), when the WebGLRenderCapability target is active, it appears that the content for certain websites (ex. https://www.vsynctester.com/) is still restricted to 60 FPS. This occurs regardless of whether the FrameRate target is active, and even regardless of whether WebGL is disabled.

Here's how I reproduced (tested on a 240hz display):

1. Ensure privacy.fingerprintingProtection is set to true.
2. Set privacy.fingerprintingProtection.overrides to +WebGLRenderCapability (or you could use something like +AllTargets,-FrameRate).
3. Restart Firefox.
4. Navigate to https://www.vsynctester.com/, observe that the FPS is always limited to 60.
5. Set privacy.fingerprintingProtection.overrides to -WebGLRenderCapability (or something like +AllTargets,-FrameRate,-WebGLRenderCapability).
6. Restart Firefox.
7. Navigate to https://www.vsynctester.com/, observe that the FPS is no longer limited to 60.

Comment 1

[lucas]

To me, I'm not sure it is restriction or limiting, it seems like honestly just raw performance lost. I can feel the rest of the page getting slow when it is enabled, and my FPS starts reporting as much lower, I don't have that great of a PC.

Unless it is intended/normal that performance is lost, I'm not sure it's even a limit

In that same test website, you can also observe it breaking V-Sync (it's nice to also disable 'ReduceTimerPrecision' in that website for visualization)

Comment 2

[lucas]

Attachment: perf-lost.png

Here's an example, 36 FPS.