994560 - CPU Priority is computed according to previous priority value

Status: RESOLVED FIXED

(Core :: General, defect)

Description

[Patrick Wang (Chih-Kai Wang) (:kk1fff)]

Attachment: Proposed patch

CPU priority is computed before we set priority to a process[1], but it is computed according to current priority[2], instead of the new priority value that we are going to set.

[1] http://dxr.mozilla.org/mozilla-central/source/dom/ipc/ProcessPriorityManager.cpp?from=processprioritymanager.cpp#985
[2] http://dxr.mozilla.org/mozilla-central/source/dom/ipc/ProcessPriorityManager.cpp?from=processprioritymanager.cpp#961

Comment 1

[Gabriele Svelto [:gsvelto]]

Comment on attachment 8404523 [details] [diff] [review]
Proposed patch

This looks good to me as it fixes some transactions we were doing incorrectly but before we land it we should really add some unit-tests to cover this particular issue. Bug 870181 had some tests which reside under dom/browser-element/mochitest/priority, see attachment 747243 [details] [diff] [review]. Those should be extended to cover this particular case.

Comment 2

[Patrick Wang (Chih-Kai Wang) (:kk1fff)]

Attachment: Proposed Patch v2

Adding cpu priority check in test case of preallocated process can cover this case. I have run the test locally, although this test is not running on TBPL before bug 987164 has been fixed.

Comment 3

[Gabriele Svelto [:gsvelto]]

Comment on attachment 8408044 [details] [diff] [review]
Proposed Patch v2

Looks good to me; BTW I've tested a few different scenarios on my phone with an w/o your patch applied and this saves us quite a few transactions while also making certain high->low transactions faster which should improve responsiveness.

Comment 4

[Patrick Wang (Chih-Kai Wang) (:kk1fff)]

Yeah, hope this can improve some in the transaction of turing preallocated to foreground as well.

Comment 5

[Patrick Wang (Chih-Kai Wang) (:kk1fff)]

https://hg.mozilla.org/integration/mozilla-inbound/rev/24496a6b3fea

Comment 6

[Ryan VanderMeulen (PTO, back July 27)]

https://hg.mozilla.org/mozilla-central/rev/24496a6b3fea