1686036 - DAMP Perf regression in panelsInBackground.reload (100%) (+ others)

Status: RESOLVED FIXED

(DevTools :: General, defect, P2)

Description

[Julian Descottes [:jdescottes]]

Several performance changes that seem linked to the error count:
https://treeherder.mozilla.org/perfherder/alerts?id=28359&hideDwnToInv=0

Most visible is a 100% regression on panelsInBackground reload.

We should take a look and investigate this.

Comment 1

[BugBot [:suhaib / :marco/ :calixte]]

Set release status flags based on info from the regressing bug 1109362

Comment 2

[Nicolas Chevobbe [:nchevobbe]]

I'll investigate this

Comment 3

[Nicolas Chevobbe [:nchevobbe]]

Attachment: Bug 1686036 - [devtools] Avoid error count icon unnecessary render. r=jdescottes.

In setErrorCount, we used to call setToolboxButtons unconditionally, which means
that it was called each time a resource was added or updated.
This was very expensive and would cause some slowness, especially on pages with
a lot of network requests, as revealed by DAMP tests.

In this patch, we don't call setToolboxButtons if the error count did not change.
On top of that, we add a throttle mechanism so the function can't be called more
than twice per second.

Comment 4

[Pulsebot]

Pushed by [e-mail]:
https://hg.mozilla.org/integration/autoland/rev/b300d2dfebc4
[devtools] Avoid error count icon unnecessary render. r=jdescottes.

Comment 5

[Julian Descottes [:jdescottes]]

Note: we regressed the performance again with https://bugzilla.mozilla.org/show_bug.cgi?id=1685985, but the patch attached here seems to fix both regressions and bring us back to the initial baseline.

https://treeherder.mozilla.org/perfherder/alerts?id=28473&hideDwnToInv=0

Comment 6

[Cristian Brindusan [:cbrindusan]]

https://hg.mozilla.org/mozilla-central/rev/b300d2dfebc4

Comment 7

[Julian Descottes [:jdescottes]]

Alert confirms the performance improvement: https://treeherder.mozilla.org/perfherder/alerts?id=28496&hideDwnToInv=0