1169742 - 3% Win7 tp5o private bytes regression on Mozilla-Inbound-Non-PGO on May 26, 2015 from push 57acaa90d7c6

Status: RESOLVED WONTFIX

(Core :: Audio/Video, defect)

Description

[Joel Maher ( :jmaher ) (UTC -8)]

Talos has detected a Firefox performance regression from your commit 57acaa90d7c6 in bug 1153123.  We need you to address this regression.

This is a list of all known regressions and improvements related to your bug:
http://alertmanager.allizom.org:8080/alerts.html?rev=57acaa90d7c6&showAll=1

On the page above you can see Talos alert for each affected platform as well as a link to a graph showing the history of scores for this test. There is also a link to a treeherder page showing the Talos jobs in a pushlog format.

To learn more about the regressing test, please see: https://wiki.mozilla.org/Buildbot/Talos/Tests#tp5

Reproducing and debugging the regression:
If you would like to re-run this Talos test on a potential fix, use try with the following syntax:
try: -b o -p win32 -u none -t tp5o  # add "mozharness: --spsProfile" to generate profile data

To run the test locally and do a more in-depth investigation, first set up a local Talos environment:
https://wiki.mozilla.org/Buildbot/Talos/Running#Running_locally_-_Source_Code

Then run the following command from the directory where you set up Talos:
talos --develop -e <path>/firefox -a tp5o

Making a decision:
As the patch author we need your feedback to help us handle this regression.
*** Please let us know your plans by Monday, or the offending patch will be backed out! ***

Our wiki page oulines the common responses and expectations:
https://wiki.mozilla.org/Buildbot/Talos/RegressionBugsHandling

Comment 1

[Joel Maher ( :jmaher ) (UTC -8)]

this is just a single patch which landed:
http://hg.mozilla.org/integration/mozilla-inbound/pushloghtml?fromchange=c8053cb8ac32&tochange=57acaa90d7c6

I did some retriggers and the private bytes went up from ~183Mb -> ~189Mb:
http://graphs.mozilla.org/graph.html#tests=[[257,132,25],[257,131,25]]&sel=1432510888776.4778,1432695140408.5251,150000000,228260869.56521738&displayrange=7&datatype=geo

Matt, can you comment on this?

Comment 2

[Joel Maher ( :jmaher ) (UTC -8)]

Matt, we will be backing this out today due to inactivity in the bug.  Please comment ASAP if there is a misunderstanding.

Comment 3

[Matt Woodrow (:mattwoodrow)]

Sorry, been a bit swamped recently.

This patch was a really big performance improvement for HTML5 video for affected machines, I think it justifies the small memory hit.

Comment 4

[Joel Maher ( :jmaher ) (UTC -8)]

ah, ok- that makes a lot of sense.  mind if we just resolve this as wontfix, or is there any desire to investigate a bit more.

Comment 5

[Matt Woodrow (:mattwoodrow)]

WONTFIX sounds fine to me.