1647611 - 15.11 - 4925.11% tp5n main_normal_fileio / ts_paint|_webext (linux64-shippable|-qr, windows10-64-shippable|-qr, windows7-32-shippable) regression on push ed8d5ec80203d89a34e68220e7d8476a22f9b867 (Mon June 22 2020)

Status: RESOLVED FIXED

(Core :: Layout: Text and Fonts, defect)

Description

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

Perfherder has detected a talos performance regression from push ed8d5ec80203d89a34e68220e7d8476a22f9b867. As author of one of the patches included in that push, we need your help to address this regression.

Regressions:

4925% tp5n main_normal_fileio windows7-32-shippable opt e10s stylo 5,682,736.42 -> 285,563,973.08
2584% tp5n main_normal_fileio windows10-64-shippable-qr opt e10s stylo 934,300.92 -> 25,077,590.42
2070% tp5n main_normal_fileio windows10-64-shippable opt e10s stylo 1,026,835.92 -> 22,284,416.08
19% ts_paint_webext linux64-shippable-qr opt e10s stylo 271.33 -> 321.67
18% ts_paint_webext linux64-shippable-qr opt e10s stylo 271.33 -> 320.58
18% ts_paint linux64-shippable-qr opt e10s stylo 268.42 -> 316.67
16% ts_paint linux64-shippable opt e10s stylo 187.42 -> 217.50
15% ts_paint_webext linux64-shippable opt e10s stylo 190.25 -> 219.00

Improvements:

68% perf_reftest bloom-basic.html macosx1014-64-shippable opt e10s stylo 14.18 -> 4.47
12% perf_reftest_singletons bidi-resolution-1.html linux64-shippable opt e10s stylo 351.94 -> 311.26
11% perf_reftest_singletons bidi-resolution-1.html linux64-shippable-qr opt e10s stylo 393.16 -> 348.64
3% startup_about_home_paint_realworld_webextensions linux64-shippable-qr opt e10s stylo 1,006.54 -> 973.00
3% startup_about_home_paint linux64-shippable-qr opt e10s stylo 992.88 -> 961.75
3% startup_about_home_paint linux64-shippable opt e10s stylo 886.58 -> 859.67
2% startup_about_home_paint_cached linux64-shippable-qr opt e10s stylo 961.33 -> 937.50

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

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

Set release status flags based on info from the regressing bug 1533462

Comment 2

[Jonathan Kew [:jfkthame]]

For the time being, I am intending to back out the pref change that triggered this, while investigating several issues that resulted. So that should revert all these regressions (and improvements) for now.