Enable dom.ipc.processPriorityManager.enabled by default on Windows

RESOLVED FIXED in Firefox 69



2 months ago
21 days ago


(Reporter: mconley, Assigned: mconley)


(Blocks 1 bug)

Dependency tree / graph

Firefox Tracking Flags

(relnote-firefox ?, firefox69 fixed)



(1 attachment)

The report in bug 1532767 shows that, according to our Beta experiment, the process priority manager had no measurable impact on page load time, tab switch time, or user retention.

So, the good news is that it doesn't appear to make things worse. However, I'm a bit sad to say that it also didn't appear to make things better (via the probes that we measure).

We do know, however, that lowering background tab process priority allows the OS to prioritize work in foreground tabs. So at the very least, this should be a resource usage win.

So I think we should go ahead and enable this and let it ride out.

Type: defect → enhancement

esmyth signed off on letting this ride the trains in Slack.

Release Note Request (optional, but appreciated)
[Why is this notable]:
This enables a component that allows Firefox to give Windows hints on how best to prioritize CPU usage. Specifically, content processes that only host tabs that are in the background will have their priorities lowered so that foreground processes can get more processor time if they need it.

[Suggested wording]:
Firefox will give Windows hints to appropriately set content process priority levels, meaning more processor time spent on the tasks you're actively working on, and less processor time spent on things in the background (with the exception of video and audio playback).

relnote-firefox: --- → ?

Comment 4

26 days ago
Pushed by mconley@mozilla.com:
Let the Process Priority Manager ride out to the release channel on Windows. r=gsvelto

Comment 5

26 days ago
Closed: 26 days ago
Resolution: --- → FIXED
Target Milestone: --- → mozilla69
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