1805932 - Put all background process Main Threads on Macos in the background

Status: RESOLVED FIXED

(Core :: XPCOM, enhancement)

Description

[Kris Wright :KrisWright]

Followup for bug 1748378, we can use this API to put all XPCOM threads in the background. We follow a few particular steps:

• Identify some IsOperatingInBackground atomic, likely held by the thread manager
• When threads see this value (eg not doing any work), they may put themselves in the background
• Threads may save their previous operating state to restore when leaving the background.

I think this process may also work for the main thread by sending a task directly to the main thread to set/unset itself.

Comment 1

[Kris Wright :KrisWright]

Attachment: Bug 1805932 - Put the main thread in the background when the ProcessPriorityManager sets background priority. r?florian,nika

Depends on D146534

Comment 2

[Kris Wright :KrisWright]

Attachment: WIP: Bug 1805932 - Implement background behavior for all nsThreads.

This part is especially tricky and what exists here so far is what I am using to test the behavior. Notifying the threads that they need to go into the background is where the main hangup is - preventing spurious wakeups while also noticing the change. To solve this I am dealing with a global background value which threads can check during dispatch. If they notice there has been a measurable change, they can dispatch to their own event target first a method to set themselves into the background. I haven't worked out yet how we'll be notifying the mechanism of the changes.

Depends on D167952

Comment 3

[Pulsebot]

Pushed by [e-mail]:
https://hg.mozilla.org/integration/autoland/rev/7f1af097474e
Put the main thread in the background when the ProcessPriorityManager sets background priority. r=nika,florian

Comment 4

[Sandor Molnar[:smolnar]]

https://hg.mozilla.org/mozilla-central/rev/7f1af097474e

Comment 5

[Phabricator Automation]

Comment on attachment 9326333 [details]
WIP: Bug 1805932 - Implement background behavior for all nsThreads.

Revision D174309 was moved to bug 1832368. Setting attachment 9326333 [details] to obsolete.

Comment 6

[Kris Wright :KrisWright]

We split up the mainthread work and any offthread work so we can move forward with testing new changes. Work on offthread changes will continue in bug 1832368.