1354255 - ElementRestyler::ComputeStyleChangeFor dynamic profiler label might have too much overhead

Status: RESOLVED FIXED

(Core :: Gecko Profiler, enhancement)

Description

[Markus Stange [:mstange]]

If the profiler is running, ComputeStyleChangeFor calls ToString() for the restyled element. This might be artificially inflating the restyle times we see in profiles.
It might be worth removing this instrumentation, until we have a way to only run it when specifically requested.

http://searchfox.org/mozilla-central/source/layout/base/GeckoRestyleManager.cpp#3061

Comment 1

[Markus Stange [:mstange]]

Attachment: Bug 1354255 - Remove ElementRestyler::ComputeStyleChangeFor profiler instrumentation due to overhead.

This only has overhead if the profiler is running, but it means that it has
the potential to skew restyle times in profiles.
We haven't measured the overhead of this, but it's probably non-zero, and at
the moment our profiling efforts are more focused on getting accurate times
than on getting useful information about restyling cost sources.

Review commit: https://reviewboard.mozilla.org/r/127356/diff/#index_header
See other reviews: https://reviewboard.mozilla.org/r/127356/

Comment 2

[(no longer active)]

Comment on attachment 8855510 [details]
Bug 1354255 - Remove ElementRestyler::ComputeStyleChangeFor profiler instrumentation due to overhead.

https://reviewboard.mozilla.org/r/127356/#review130088

Thank you!

Comment 3

[Pulsebot]

Pushed by [e-mail]:
https://hg.mozilla.org/integration/autoland/rev/596704d5da99
Remove ElementRestyler::ComputeStyleChangeFor profiler instrumentation due to overhead. r=Ehsan

Comment 4

[Carsten Book [:Tomcat]]

https://hg.mozilla.org/mozilla-central/rev/596704d5da99

Comment 5

[Carsten Book [:Tomcat]]

https://hg.mozilla.org/mozilla-central/rev/596704d5da99