1906756 - Profiler doesn't capture gecko log properly when playing a local video file

Status: RESOLVED WORKSFORME

(Core :: Gecko Profiler, defect, P3)

Description

[Alastor Wu [:alwu]]

STR.

1. download this videowhich is from bug 1905022
2. go to about:logging and select Media playback preset
3. start profiling
4. open new tab and play the video you downloaded from the step1.
5. make the video playing for 1 second
6. go back to about:logging and stop profiling

Expect.
7. We should see logging in the MediaDecoderStateMachine thread

Actual.
7. No logging can be seen in the MediaDecoderStateMachine thread

---

This shows an issue which is when playing a local file media, the logging won't be captured by Firefox profiler. If you play a file over internet, eg. https://bug1905022.bmoattachments.org/attachment.cgi?id=9409858. Then you can see that logs will be captured successfully.

Comment 1

[Nazım Can Altınova [:canova][:canaltinova on phabricator]]

I tried to capture a profile with a local video like you suggested and I managed to get log messages. Here's an example profile: https://share.firefox.dev/3SjkDIy

Am I doing something differently? Could you check one more time to see if you can reproduce the issue?

Comment 2

[Alastor Wu [:alwu]]

So this seems a Windows only issue. I tried it again on the latest Nightly and the issue still exists. No logging can be found in this profile.

Comment 3

[Alastor Wu [:alwu]]

Recently we have received more profiled results which are apparently lacking the necessary information. Eg. in bug 1904394 comment11, it lacks of the debug logs.

Another one from an user who was helping me profiling a Youtube issue. The weird thing for that is no any media threads captured in the Youtube tab (pid: 15636). But by looking the GPU process, the media threads and logs was indeed captured. According to the reporter, this situation only happens when the certain Youtube problem appears (video stutter for a several seconds)

Nazım, would you think of any possible reasons of missing the debug log, or entire threads and logs for the profiler? Thank you!

Comment 4

[Nazım Can Altınova [:canova][:canaltinova on phabricator]]

I couldn't get back to this yet, sorry about that. Hopefully I should be able to look at it soon. But it also feels like it might not be profiler related issue.

Comment 5

[Nazım Can Altınova [:canova][:canaltinova on phabricator]]

I believe the root cause of this is the same as bug 1914388 and considering that it's fixed, this one should be fixed as well.

@Alastor could you confirm if this is fixed now?

Comment 6

[Alastor Wu [:alwu]]

I can confirm this issue no longer happens on the latest Nightly, close this bug.