1796525 - Set background content process to the EcoQoS on Windows 11

Status: RESOLVED FIXED

(Core :: Hardware Abstraction Layer (HAL), task)

Description

[Florian Quèze [:florian]]

This can be done by using the SetProcessInformation function. We can do it at the same time as we set the process priority to background.

Comment 1

[Florian Quèze [:florian]]

Attachment: Bug 1796525 - Set the QoS of background content processes to 'eco', r=gsvelto.

Comment 2

[Pulsebot]

Pushed by [e-mail]:
https://hg.mozilla.org/integration/autoland/rev/b91afc20f8f9
Set the QoS of background content processes to 'eco', r=gsvelto.

Comment 3

[Iulian Moraru]

https://hg.mozilla.org/mozilla-central/rev/b91afc20f8f9

Comment 4

[Florian Quèze [:florian]]

Release Note Request (optional, but appreciated)
[Why is this notable]: A green leaf icon will be visible in the Windows 11 22H2 Task Manager next to some Firefox processes.
In most cases this should either have no effect (eg. on machines running on older versions of Windows), or result in a nice power use reduction. In some extreme testcases, I saw power use caused by a background tab be divided by 5 (this was when testing on an Intel Core 12th gen CPU on Windows 11 22H2). In other tests (bug 1800412 comment 6 ; older CPU and older version of Windows 11) this patch only helped when the machine was running on battery, but provided a nice power use reduction in that case, which should help with battery life.
If for some reason some users are negatively affected (eg. if they rely on background tabs having maximum performance), the dom.ipc.processPriorityManager.backgroundUsesEcoQoS preference can be used from about:config to disable the feature.
[Affects Firefox for Android]: no
[Suggested wording]: Processes used for background tabs now use efficiency mode on Windows 11 to limit resource use.
[Links (documentation, blog post, etc)]:

Comment 5

[Florian Quèze [:florian]]

Attachment: Screenshot of how this looks like in the task manager