1354961 - Make ProfileGatherer grab the profile of the parent process on a background thread

Status: RESOLVED INVALID

(Core :: Gecko Profiler, enhancement)

Description

[Markus Stange [:mstange]]

I'm going to attach a few patches that make us call the profile gathering functions on a background thread. This is in preparation for bug 1330185, which will hopefully create a communication channel from a background thread in the parent process to a background thread on each other process.

Generating the JSON for the parent process profile on a background thread might be a good thing to do anyway, in order to reduce the jank that occurs during profile gathering. However, as is, these patches don't help much with the jank because the main thread sooner or later calls a function that accesses the profiler state, like profiler_is_active(), and then it just blocks until the background thread is done with the profile collection.

Comment 1

[Markus Stange [:mstange]]

Attachment: Bug 1354961 - Use MozPromise to make ProfileGatherer more generic.

Review commit: https://reviewboard.mozilla.org/r/128200/diff/#index_header
See other reviews: https://reviewboard.mozilla.org/r/128200/

Comment 2

[Markus Stange [:mstange]]

Attachment: Bug 1354961 - Do profile gathering on a separate thread.

Review commit: https://reviewboard.mozilla.org/r/128202/diff/#index_header
See other reviews: https://reviewboard.mozilla.org/r/128202/

Comment 3

[Markus Stange [:mstange]]

Attachment: Bug 1354961 - Disable main thread asserts and some other main thread stuff when serializing the profile.

Review commit: https://reviewboard.mozilla.org/r/128204/diff/#index_header
See other reviews: https://reviewboard.mozilla.org/r/128204/

Comment 4

[Markus Stange [:mstange]]

This makes things too complicated and isn't worth doing at this point. I'm going to go ahead with keeping the collection of the *parent process* profile on its main thread, and only do profile collection for *content processes* on a background thread.