1640100 - 8% Heap Unclassified (linux1804-64-shippable-qr) regression on push 0caead34be39e30750098ceaf5738dd0d1850273 (Fri May 15 2020)

Status: RESOLVED WONTFIX

(Core :: Graphics: WebRender, defect)

Description

[Florin Strugariu [:Bebe]]

Perfherder has detected a awsy performance regression from push 0caead34be39e30750098ceaf5738dd0d1850273. As author of one of the patches included in that push, we need your help to address this regression.

Regressions:

8% Heap Unclassified linux1804-64-shippable-qr opt tp6 234,925,751.24 -> 253,726,649.87

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 1555356

Comment 2

[Dzmitry Malyshau [:kvark]]

Florin, push https://hg.mozilla.org/integration/autoland/pushloghtml?changeset=0caead34be39e30750098ceaf5738dd0d1850273 doesn't appear to be relevant. Is this a mistake?
Marking as S2 to figure out if this needs to be fixed, or expected, soonish.

Comment 3

[Florin Strugariu [:Bebe]]

Sorry for the confusion here is the correct commit message:
https://treeherder.mozilla.org/#/jobs?repo=autoland&group_state=expanded&revision=a86dcd6715c9e52fdd8e4a937b5e94ea2b9a5fcb&selectedTaskRun=VwpKOLjhSw6v73fx3tGwfg-0

Here is graph with the commit selected:
https://treeherder.mozilla.org/perf.html#/graphs?highlightAlerts=1&highlightedRevisions=a86dcd6715c9e52fdd8e4a937b5e94ea2b9a5fcb&series=autoland,2242027,1,4&timerange=1209600&zoom=1589549501823,1589575638224,206729629.64152265,271494101.1454798

Comment 4

[Dzmitry Malyshau [:kvark]]

Thank you!. Leaving for Bert to look at.

Comment 5

[Bert Peers [:bpeers]]

Thanks Florin, please revert this, I won't have an answer for this on short notice.

Comment 6

[Aria Beingessner [:Gankra]]

PSA: when i started this patch, it was to even see if it was good/bad for perf. So, test "successful" I suppose.

Comment 7

[Darkspirit]

(In reply to Bert Peers [:bpeers] from comment #5)

Thanks Florin, please revert this, I won't have an answer for this on short notice.

But a backout of bug 1555356 would revert all other improvements (bug 1555356 comment 19) and reintroduce bug 1603899.

Comment 8

[Tim Spurway [:tspurway]]

S1 or S2 bugs need an assignee - could you find someone for this bug?

Comment 9

[Jessie [:jbonisteel] pls NI]

Bert to confirm, was this perf hit on Linux only?

Comment 10

[Darkspirit]

bug 1555356 comment 17 was pushed 2020-05-15. It changed WebRender display list items.
https://treeherder.mozilla.org/perf.html#/graphs?highlightAlerts=1&highlightedRevisions=a86dcd6715c9e52fdd8e4a937b5e94ea2b9a5fcb&series=autoland,2242027,1,4&series=autoland,2242077,1,4&series=autoland,2242228,1,4&timerange=2592000
You can see the regression on Linux-WR (only enabled on Nightly), but not on Linux or Windows-WR. Therefore I had set 78 and 79 status flags to disabled.

Comment 11

[Bert Peers [:bpeers]]

I believe Jan Andre has answered this one, assuming Windows-WR and Linux-WR measure the same things with the same fidelity?
If so, thanks Jan Andre! :)

Comment 12

[Julien Cristau [:jcristau] (back August 18)]

Florin, what's the next step here?

Comment 13

[Florin Strugariu [:Bebe]]

if we accept this regression we can close this as won't fix.

Comment 14

[Julien Cristau [:jcristau] (back August 18)]

WR is not shipping on linux in 78 so I guess we can call this disabled.

Comment 15

[Robert Longson [:longsonr]]

The code path in bug 1555356 has been preffed off in by bug 1684625. That will fix this regression temporarily till the pref gets switched on.

Comment 16

[Glenn Watson [:gw]]

Too long ago to do anything about this now.