1645967 - 1.24 - 3.06% ts_paint_webext (windows10-64-shippable) regression on push 6be570e963dec97af0d0ceffd0b3526d284304aa (Wed June 10 2020)

Status: RESOLVED FIXED

(Firefox :: Address Bar, defect, P2)

Description

[Alexandru Ionescu (needinfo me) [:alexandrui]]

Perfherder has detected a talos performance regression from push 6be570e963dec97af0d0ceffd0b3526d284304aa. As author of one of the patches included in that push, we need your help to address this regression.

Regressions:

3% ts_paint_webext windows10-64-shippable opt e10s stylo 304.92 -> 314.25
1% ts_paint_webext windows10-64-shippable opt e10s stylo 309.83 -> 313.67

Details of the alert can be found in the alert summary, including links to graphs and comparisons for each of the affected tests. Please follow our guide to handling regression bugs and let us know your plans within 3 business days, or the offending patch(es) will be backed out in accordance with our regression policy.

For more information on performance sheriffing please see our FAQ.

Comment 1

[Marco Bonardo [:mak] (Away 10-21 August)]

ah, this is really strange, unless ts_paint is wrongly opening the empty urlbar, but them we should have seen a similar increase much sooner.

Comment 2

[Marco Bonardo [:mak] (Away 10-21 August)]

the bad news is that it's not possible to get a profile because g5-profiling times out with something similar to bug 1599588.

Comment 3

[BugBot [:suhaib / :marco]]

Set release status flags based on info from the regressing bug 1631848

Comment 4

[Marco Bonardo [:mak] (Away 10-21 August)]

I got a profile locally, I see a couple things
UrlbarProviderSearchTips.jsm is reported for the lastBrowserUpdateDate that seems quite expensive to do during Ts. Also isBrowserShowingNotifications appears. Both are invoked from onLocationChange. We should look at ideas to improve that, but it's not strictly related to this bug, so I'll file it apart.

Related to this bug, the UrlbarProvidersManager initializes the various providers, among which also UrlbarProviderTopSites that immediately runs "resource://activity-stream/common/Reducers.jsm", because of the defineLazyPreferenceGetter (the default value is not lazy!)

Comment 5

[Marco Bonardo [:mak] (Away 10-21 August)]

Attachment: Bug 1645967 - Avoid immediate import of Reducers.jsm in UrlbarProviderTopSites.jsm. r=adw

Comment 6

[Pulsebot]

Pushed by [e-mail]:
https://hg.mozilla.org/integration/autoland/rev/fc7a7af72814
Avoid immediate import of Reducers.jsm in UrlbarProviderTopSites.jsm. r=adw

Comment 7

[Razvan Maries]

https://hg.mozilla.org/mozilla-central/rev/fc7a7af72814