1704520 - 0.34 - 0.34% Base Content JS / Base Content JS (OSX) regression on Fri April 9 2021

Status: RESOLVED WONTFIX

(Core :: DOM: Device Interfaces, defect)

Description

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

Perfherder has detected a awsy performance regression from push 454b8e6f3a5d27ad6e92c17f523ddb4e18e03a0b. As author of one of the patches included in that push, we need your help to address this regression.

Regressions:

Ratio	Suite	Test	Platform	Options	Absolute values (old vs new)
0.34%	Base Content JS		macosx1015-64-shippable-qr		2,408,288.00 -> 2,416,544.00
0.34%	Base Content JS		macosx1015-64-shippable-qr		2,408,288.00 -> 2,416,544.00

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

[Kagami Rosylight [:saschanaz] (they/them)]

Hmm? I don't think the basic IDL addition can cause any perf regression, unless there is a hidden IDL layer issue. 🤔

Comment 2

[Kagami Rosylight [:saschanaz] (they/them)]

Reverting it does restore it, which is mysterious to me. There could be potential perf bottleneck in IDL side, or not 🤷‍♀️

https://treeherder.mozilla.org/perfherder/comparesubtest?originalProject=try&newProject=try&originalRevision=2009ddf265dc1645e835554496431d8051127db7&newRevision=e4b7a4d5b1ed20e84d5bc0904ec0c91e97753747&originalSignature=3183256&newSignature=3183256&framework=4

NI'ing :smaug for visibility.

Comment 3

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

Set release status flags based on info from the regressing bug 1697093

Comment 4

[Kagami Rosylight [:saschanaz] (they/them)]

Okay, so it seems that we are at a boundary that adding more attributes doubles the dynamic slot. Since we are expected to add more and more attributes, this regression should be accepted.