1508205 - Make sure that markers don't leak when profiler stops and/or thread should not be profiled

Status: RESOLVED FIXED

(Core :: Gecko Profiler, enhancement, P3)

Description

[Gerald Squelart (he/him) (not at Mozilla since 2022-09-15)]

Markers are recorded when the profiler is active and the thread is marked for profiling.

But because these conditions are read from "racy" atomic variables (they are not tied to the profiler lock) before some work is done, it may be possible for some thread to observe not-up-to-date values, or more likely observe values but then by the time the actual work is happening these values may have changed.
In particular, some markers could get recorded after the profiler is stopped.

We should make sure that these spurious late markers are not a problem:
- If captured in a profile, the front-end should be able to deal with them (either discard them, or correctly display them),
- We should make sure that they don't leak.

Comment 1

[Gerald Squelart (he/him) (not at Mozilla since 2022-09-15)]

Marking this bug FIXED thanks to Markers 2.0 and the new ProfileChunkedBuffer storage, which guarantees that markers cannot take space when the profiler is not running.