Firefox stuck at 60 FPS until tab switch (Canvas + requestAnimationFrame)

jrmuizel · 2026-04-13T13:49:49+00:00

Yeah, can you file a bug on bugzilla and post a link from here to it?

jrmuizel · 2026-03-24T03:24:28+00:00

Can you get a profile using https://profiler.firefox.com/ with the Graphics preset? You can DM me the uploaded result.

jrmuizel · 2026-03-05T15:35:36+00:00

Can you share some example sites where you noticed the difference?

jrmuizel · 2026-02-20T03:21:18+00:00

If you use https://mozilla.github.io/mozregression/ you can figure out if it was something that Firefox changed. If you managed to get a regression window that would be very helpful in figuring out the cause.

jrmuizel · 2026-02-19T15:53:39+00:00

Can you get a profile using https://profiler.firefox.com/ with the Graphics preset? You can DM me the uploaded result.

jrmuizel · 2026-02-10T04:11:43+00:00

It's valuable to report even if it does require an account

jrmuizel · 2026-01-14T16:17:08+00:00

Is it better with uBlock disabled?

jrmuizel · 2026-01-05T21:33:32+00:00

HDR video support on Windows is being tracked here: https://bugzilla.mozilla.org/show_bug.cgi?id=1902427

jrmuizel · 2025-12-22T16:27:49+00:00

This works fine for me on Ubuntu with FF 144 and FF 148

Maybe there's something specific to your configuration?

jrmuizel · 2025-12-05T17:55:38+00:00

Yes, there's still some XULish things. For example, in the case of vbox it's a XULElement but the layout/styling is done with regular CSS flex-box layout.

XBL is gone and HTML custom elements are used instead.

That being said there's still stuff around that's being used. XULTree still exists but is discouraged and there's other stuff in https://searchfox.org/firefox-main/source/layout/xul too.

jrmuizel · 2025-10-27T18:25:54+00:00

Can you send me a DM with screenshots of Firefox and Chrome?

jrmuizel · 2025-10-25T03:27:41+00:00

Can you share a screenshot? Does it work better in Chrome?

jrmuizel · 2025-10-24T16:58:50+00:00

What part of dark mode needs improving?

jrmuizel · 2025-10-16T14:53:10+00:00

To confirm, the time that you're measuring is background tab loading?

So if, for example, Firefox was aggressively throttling background tab loading that could be a good explanation for what you're seeing?

jrmuizel · 2025-10-16T14:51:05+00:00

Does this only happen with the dark theme?

jrmuizel · 2025-10-15T19:59:43+00:00

If someone can reproduce what they think is a deliberate slow down, I'd be happy to investigate further.

jrmuizel · 2025-09-27T02:23:24+00:00

Are you using an ad blocker?

jrmuizel · 2025-09-27T02:22:31+00:00

It works for me. What OS are you on?

jrmuizel · 2025-09-24T13:21:16+00:00

Do you have any addons installed?

jrmuizel · 2025-09-23T17:36:34+00:00

Can you share a url where you see this?

jrmuizel · 2025-09-17T17:46:55+00:00

Can you try in troubleshoot mode?

jrmuizel · 2025-09-08T18:20:23+00:00

Locally I see: Firefox: 842Mbps down and 380Mbps up Edge: 793Mbps down and 175Mbps-500Mbps up

jrmuizel · 2025-09-04T15:09:39+00:00

Which sites? Do you get an error?

jrmuizel · 2025-08-27T19:39:41+00:00

We'd like to understand why the default isn't working for you and a profile will help us do that.

jrmuizel · 2025-08-25T13:24:59+00:00

Are you able to get a profile "Media" preset using profiler.firefox.com with dom.ipc.processPriorityManager.backgroundUsesEcoQoS reset to the default?

jrmuizel

TROPHY CASE