1315658 - Implement option to simulate CPU throttling

Status: REOPENED

(DevTools :: Performance Tools (Profiler/Timeline), enhancement, P3)

Description

[Soledad Penades [:sole] [:spenades]]

Slow networks don't accurately represent low-end devices on a slow connection. We also need to slow down code execution.

Comment 1

[Mark]

Don't forget that besides slow code execution, you also need slow rendering capabilities (for animated effects) and slow event dispatching.

Comment 2

[:Harald Kirschner :digitarald]

Moving to Profiler as CPU performance is more contextual (can be exposed elsewhere, of course)

Comment 3

[Gerald Squelart (he/him) (not at Mozilla since 2022-09-15)]

Tech detail: Another product is simulating CPU throttling by regularly suspending their main thread. It should be possible to do that from our profiler sampling loop, somewhere around there: https://searchfox.org/mozilla-central/rev/5a4aaccb28665807a6fd49cf48367d47fbb5a19a/tools/profiler/core/platform.cpp#3220
(And all that code could be copied/reused elsewhere if we wanted to throttle without using the profiler.)

Comment 4

[Jan Honza Odvarko [:Honza] (always need-info? me)]

This report is related to the old DevTools Profiler.
The Performance panel now points to the new Firefox profiler available at profiler.firefox.com
Closing as Invalid bug

Comment 5

[Julien Wajsberg [:julienw]]

I believe this is still valid.

Comment 6

[matthewrister]

The new Firefox profiler doesn't provide a mechanism to simulate CPU throttling similar to Chrome DevTools.