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Issue 615594 link

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Issue metadata

Status: Archived
Owner: ----
Closed: Sep 2017
Cc:
Components:
EstimatedDays: ----
NextAction: ----
OS: ----
Pri: 3
Type: Bug



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Very strange blink_perf.layout large-table-with-collapsed-borders results

Project Member Reported by sullivan@chromium.org, May 28 2016

Issue description

The dashboard accidentally filed two bugs and kicked off two bisects on the exact same regression:

  https://chromeperf.appspot.com/group_report?bug_id=615418

The bisects are http://build.chromium.org/p/tryserver.chromium.perf/builders/win_perf_bisect/builds/6541 and http://build.chromium.org/p/tryserver.chromium.perf/builders/win_perf_bisect/builds/6540

They both got really similar results, with r395578 taking longer than the other runs. But r395578 just marks some tests flaky:


===== TESTED REVISIONS =====
Revision         Mean     Std Dev  N  Good?
chromium@395578  301.978  1.90187  5  good
chromium@395579  294.852  2.51474  5  bad    <--
chromium@395580  292.373  2.50669  5  bad
chromium@395582  289.705  2.00795  5  bad
chromium@395586  295.306  1.23845  5  bad
chromium@395594  292.013  2.57381  5  bad


chromium@395578  302.725  2.71425  12  good
chromium@395579  295.684  3.35878  8   bad    <--
chromium@395580  293.139  2.39214  5   bad
chromium@395582  290.119  2.07695  5   bad
chromium@395586  295.575  3.11144  5   bad
chromium@395594  298.497  5.14943  12  bad

Looking farther down the graphs, another thing is weird: the ref build on both graphs jumps around r395965 even though there are no changes to the test or telemetry, that's just the same build of chrome stable we used for all the runs before it.

I think something is strange about this test. Emil, any ideas?
 
It's possible that someone update the html resources of this test?

Comment 3 by aiolos@chromium.org, May 28 2016

Cc: aiolos@chromium.org
Annie: it's possible that the jump to both TOT & ref is due to some hardware change then.

Comment 5 by e...@chromium.org, May 31 2016

That's truly bizarre. Really looks like either the test itself or the way we run it changed between those two runs. Can't find anything relevant anywhere near that regression range though.
Hmhh, I think that there is a bug in telemetry or the recipe that make the ref build system no longer work. I am looking at  issue 614858  & found that the tracing_over_head of ref build just regressed, which seems impossible due to just hardware/test change.
At least for this case, I can confirm this is either a bug in recipe or a bug in dashboard. I clicked on the graph of large-table-with-collapsed-borders-and-colspans.html_ref, then click on "Buildbot stdio" link & here is the log:

https://build.chromium.org/p/chromium.perf/builders/Win%207%20Low-End%20Perf%20%282%29/builds/3818/steps/blink_perf.layout/logs/stdio

The benchmark command in the log is:
C:\b\build\slave\Win_7_Low-End_Perf__2_\build\src\tools\perf\run_benchmark' -v '--output-format=chartjson' --upload-results blink_perf.layout '--browser=release'
TUUj8ctv0Dm.png
508 KB View Download

Comment 8 by e...@chromium.org, Jun 1 2016

Components: -Blink>Layout -Tests>AutoBisect

Comment 9 by dtu@chromium.org, Sep 13 2017

Status: Archived (was: Untriaged)

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