1770758 - 3.59% build times (Windows) regression on Tue May 17 2022

Status: NEW

(Developer Infrastructure :: Source Code Analysis, defect, P3)

Description

[Andra Esanu (needinfo me)]

Perfherder has detected a build_metrics performance regression from push 1254448a9518995f5922080912755262c984bdfd. 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)
4%	build times	windows2012-64	plain taskcluster-c4.4xlarge	2,923.97 -> 3,029.00

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) (OOO until 2024-10-06)]

I believe maybe it's busy emitting warning to stderr? Bug 1769290 will ultimately reduce the warning count to zero, and we are discussing how to do that.

Could be also that the type name stringification is slowing things down, I wonder what could solve that.

Comment 2

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

Set release status flags based on info from the regressing bug 1766038

Comment 3

[Masayuki Nakano [:masayuki] (he/him)(JST, +0900)]

(In reply to Kagami :saschanaz from comment #1)

I believe maybe it's busy emitting warning to stderr?

On Windows, the prompt blocks the process until painting whole lines coming from stdout/stderr. Therefore, if the treeherder uses the prompt, this is the cost on Windows specific. Otherwise, if the treeherder does not use the prompt (e.g., just putting only into a file), it means that the build speed for developers is now slower than what this bug reports.

Comment 4

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

Set release status flags based on info from the regressing bug 1766038

Comment 5

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

The severity field is not set for this bug.
:andi, could you have a look please?

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