1685539 - 8.3 - 10.64% Base Content Resident Unique Memory / Resident Memory (macosx1014-64-shippable-qr) regression on push ed96e8c21b5a64eea14f8efe7b595fd76117fb80 (Tue January 5 2021)

Status: RESOLVED WONTFIX

(Core :: JavaScript: GC, defect)

Description

[Andra Esanu (needinfo me)]

Perfherder has detected a awsy performance regression from push ed96e8c21b5a64eea14f8efe7b595fd76117fb80. 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)
11%	Resident Memory		macosx1014-64-shippable-qr	tp6	725,120,144.23 -> 802,272,238.55
9%	Base Content Resident Unique Memory		macosx1014-64-shippable-qr		16,610,816.00 -> 18,112,000.00
8%	Resident Memory		macosx1014-64-shippable-qr	tp6	734,640,536.30 -> 795,646,398.75

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

[Steve Fink [:sfink] [:s:]]

This regression is expected, see bug 1682947 comment 7. (Is there a better way to warn of things like this?)

The regression is entirely due to improved reporting of RSS. OSX requires an additional system call in order to update its memory accounting properly. Our previous numbers were incorrect.