1818344 - Low priority timers should be dispatched at a priority lower than normal

Status: ASSIGNED

(Core :: XPCOM, enhancement)

Description

[Florian Quèze [:florian]]

Currently all timers are dispatched at a normal priority. This is confusing as the timer API exposes the following types that sounds like they would cause the timer callback to run at a lower priority:

• TYPE_REPEATING_SLACK_LOW_PRIORITY
• TYPE_ONE_SHOT_LOW_PRIORITY

Comment 1

[Florian Quèze [:florian]]

Attachment: Bug 1818344 - dispatch low priority timers to the main thread at a low priority, r=Bas

Comment 2

[Florian Quèze [:florian]]

I'm not sure what the actual priority should be. The attached patch uses EventQueuePriority::Low, but I mostly put it up there for discussion.

I think what low priority means in the nsITimer API isn't very well defined, so it's probably a matter of guessing what behavior the developers who used them wanted to have.

Comment 3

[Olli Pettay [:smaug][[e-mail]]]

lower priority timers don't have anything to do with priority on the target thread. They are there just for idle handling.
Perhaps their name should be changed though.

Comment 4

[Olli Pettay [:smaug][[e-mail]]]

I'm fine adding some mechanism to lower the priority, but let's not break the existing API.