1691421 - 4.08 - 22.74% Explicit Memory / Heap Unclassified (windows10-64-shippable-qr) regression on push 2f575c3c4353b2c5adc27519e55ca4f3c125a1d2 (Fri February 5 2021)

Status: RESOLVED FIXED

(Core :: Graphics: WebRender, defect)

Description

[Andra Esanu (needinfo me)]

Perfherder has detected a awsy performance regression from push 2f575c3c4353b2c5adc27519e55ca4f3c125a1d2. 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)
23%	Heap Unclassified		windows10-64-shippable-qr	tp6	58,169,417.77 -> 71,398,471.81
21%	Heap Unclassified		windows10-64-shippable-qr	tp6	58,601,231.23 -> 71,068,188.49
10%	Heap Unclassified		windows10-64-shippable-qr		51,628,678.47 -> 56,956,852.12
4%	Explicit Memory		windows10-64-shippable-qr	tp6	448,803,321.86 -> 467,119,287.80

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

[Nicolas Silva [:nical]]

There's a few low hanging fruits to avoid retaining too many staging textures.

Comment 2

[Nicolas Silva [:nical]]

Attachment: Bug 1691421 - Report staging texture memory. r=jrmuizel

Comment 3

[Nicolas Silva [:nical]]

Attachment: Bug 1691421 - Improve the way stalls are avoided in the staging texture pool. r=jnicol

Instead of using a triple buffering scheme, tag each texture with a frame index and only reuse a texture that hasn't been used for more than two frames.

Depends on D104420

Comment 4

[Nicolas Silva [:nical]]

Attachment: Bug 1691421 - Shrink the staging texture pool automatically. r=jnicol

If we have more than 8 unused/reusable staging textures and buffers for more than 120 consecutive frames, start deallocation them, spreading the deallocation over multiple frames.
The vast majority of frames require less than 4 staging textures and buffers (most don't require any), but some SVG animations can put a lot of pressure on uploads, requiring 30+ staging textures per frame. This patch avoids staying at this kind of peak memory usage for too long.

Depends on D104421

Comment 5

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

Set release status flags based on info from the regressing bug 1690247

Comment 6

[Pulsebot]

Pushed by [e-mail]:
https://hg.mozilla.org/integration/autoland/rev/05436e3d6db9
Report staging texture memory. r=gfx-reviewers,jrmuizel
https://hg.mozilla.org/integration/autoland/rev/802a5cf1ca38
Improve the way stalls are avoided in the staging texture pool. r=jnicol
https://hg.mozilla.org/integration/autoland/rev/b9370586b586
Shrink the staging texture pool automatically. r=jnicol

Comment 7

[Natalia Csoregi [:nataliaCs]]

https://hg.mozilla.org/mozilla-central/rev/05436e3d6db9
https://hg.mozilla.org/mozilla-central/rev/802a5cf1ca38
https://hg.mozilla.org/mozilla-central/rev/b9370586b586

Comment 8

[Andra Esanu (needinfo me)]

== Change summary for alert #28747 (as of Thu, 11 Feb 2021 12:21:25 GMT) ==

Improvements:

Ratio	Suite	Test	Platform	Options	Absolute values (old vs new)
18%	Heap Unclassified		windows10-64-shippable-qr	tp6	71,793,894.86 -> 58,721,642.48
17%	Heap Unclassified		windows10-64-shippable-qr	tp6	70,957,530.93 -> 58,745,692.46
7%	Heap Unclassified		windows10-64-shippable-qr		56,838,791.71 -> 52,856,789.97

For up to date results, see: https://treeherder.mozilla.org/perfherder/alerts?id=28747