1777427 - 5.69% assorted-dom (Windows) regression on Thu June 16 2022

Status: RESOLVED INVALID

(Core :: JavaScript Engine: JIT, defect)

Description

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

Perfherder has detected a browsertime performance regression from push 103f879d45ff94ed79464af1fce977e54e6ac6e9. As author of one of the patches included in that push, we need your help to address this regression.

Regressions:

Ratio	Test	Platform	Options	Absolute values (old vs new)
6%	assorted-dom	windows10-64-shippable-qr	fission webrender	19.43 -> 20.54

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.

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Comment 1

[Jan de Mooij [:jandem]]

Thanks for filing. Looking at the graph, this went back to normal, but it's possible the frame pointer changes made this go up and down a bit with particular changes. Random changes in cache lines and stack alignment often affect micro-benchmarks a lot unfortunately.