Drno sees this in a call using whereby.com.

Here are some profiles:

WR on: https://share.firefox.dev/3fhPUWt

WR off: https://share.firefox.dev/2UsEF5m

NI-ing Jeff to take a peak at the profiles

Yeah, so there's something really bad going on in the Renderer thread. It looks like we're spending a lot of time waiting for the GPU.

Nils, how easy it for you to reproduce this? Do you have multiple GPUs in the mac where you see this?

This is trivial to repro for me: I only have to do a WebRTC based 1:1 call on whereby.com while using my external monitor.

And yes my 2018 MBP has:

• Intel UHD Graphics 630
• Radeon Pro 560X

Attaching about:support

I think this might need bug 1600178 to be fixed. Can you reproduce the problem when not using the external monitor?

Might also be noteworthy that my external monitor is 4K HDR10 and since I'm running 10.15.5 the monitor is running in HDR mode.

Can you retest this with today's Nightly? 20200708094217 or newer?

@Nils: can you check if this is still happening?

(In reply to Nils Ohlmeier [:drno] from comment #6)

@Nils: can you check if this is still happening?

Declaring NI bankruptcy.