1094763 - ThreadSources.prototype._sourceForScript dominates profiler

Status: RESOLVED WONTFIX

(DevTools :: Debugger, defect)

Description

[The 8472]

Attachment: profiler output with devtools dominating CPU time

When attempting to profile an addon through the toolbox it seems that the toolbox itself is dominating in the profiler results.

This distorts the call tree since it appears in several leaf calls and gets accumulated into the total time.
And I guess this might also point at some inefficiency in the Debugger/Profiler.


Workaround: Use the inverted tree, ignore ThreadSources (the dominating entry) and focus on self-time of the methods.

Comment 1

[Nick Fitzgerald [:fitzgen] [⏰PST; UTC-8]]

What is the bug being reported here? That there is jank/performance degradation caused by ThreadSources.prototype._sourceForScript, or that non-addon related frames are shown in the profiler's call tree?

Comment 2

[The 8472]

>That there is jank/performance degradation caused by ThreadSources.prototype._sourceForScript

Yes.

And the devtools themselves distorting profiler results while you're using the devtools is also an issue in itself. I mean I can't profile when I turn the devtools off to eliminate this, can I?

I am actually experiencing jank simply by having the toolbox open, not just when profiling, but this was the most obvious issue to report.

>or that non-addon related frames are shown in the profiler's call tree?

No

Comment 3

[Jason Laster [:jlast]]

Closing as _sourceForScript no longer exists and either way we should re-profile after 5 years :)