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Issue 770844 link

Starred by 1 user
Status: Duplicate
Merged: issue 770454
Owner: ----
Closed: Oct 2017
Cc:
kouhei@chromium.org
█ nednguyen@chromium.org
ksakamoto@chromium.org
charliea@chromium.org
EstimatedDays: ----
NextAction: ----
OS: ----
Pri: 2
Type: Bug-Regression



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3.6%-40% regression in timeToFirst{Contentful, Meaningful}Paint at 504932:505463

Project Member Reported by majidvp@chromium.org, Oct 2 2017 
The metric has regressed on both mobile and desktop which is manifest in loading.desktop and system_health.common_mobile.
Project Member

Comment 1 by 42576172...@developer.gserviceaccount.com, Oct 2 2017 

All graphs for this bug:
  https://chromeperf.appspot.com/group_report?bug_id=770844

(For debugging:) Original alerts at time of bug-filing:
  https://chromeperf.appspot.com/group_report?sid=15f4f2403bdc94ccca310a2b4e1cf59d5f523ae2f0385d06b9efdad38d69d875


Bot(s) for this bug's original alert(s):

android-nexus5
android-nexus5X
android-nexus6
android-nexus7v2
android-one
android-webview-nexus5X
android-webview-nexus6
chromium-rel-mac-retina
chromium-rel-mac11-air
chromium-rel-mac11-pro
chromium-rel-mac12
chromium-rel-mac12-mini-8gb
chromium-rel-win10
chromium-rel-win7-dual
chromium-rel-win7-gpu-intel
chromium-rel-win7-gpu-nvidia
chromium-rel-win7-x64-dual
linux-release
win-high-dpi

Comment 3 by ksakamoto@chromium.org, Oct 3 2017

Cc: -kou...@chormium.org kouhei@chromium.org
Project Member

Comment 4 by 42576172...@developer.gserviceaccount.com, Oct 3 2017

Mergedinto: 770454
Status: Duplicate (was: Untriaged)

=== BISECT JOB RESULTS ===
Perf regression found with culprit

Suspected Commit
  Author : Marja Hölttä
  Commit : 40856948a64e2b76bc121a8841a763836dbf1b37
  Date   : Thu Sep 28 12:41:56 2017
  Subject: [parser] Skipping inner funcs: Turn off FLAG_preparser_scope_analysis.

Bisect Details
  Configuration: win_perf_bisect
  Benchmark    : loading.desktop
  Metric       : cpuTimeToFirstMeaningfulPaint_avg/warm/IGN
  Change       : 14.26% | 340.772666667 -> 389.370916667

Revision                           Result                  N
chromium@505142                    340.773 +- 30.2371      6      good
chromium@505190                    327.585 +- 29.6203      6      good
chromium@505202                    332.827 +- 41.251       6      good
chromium@505208                    328.593 +- 29.1046      6      good
chromium@505210                    324.234 +- 29.0579      6      good
chromium@505210,v8@4ba6f15ece      324.268 +- 28.9472      6      good
chromium@505210,v8@40856948a6      392.75 +- 27.4299       6      bad       <--
chromium@505210,v8@193dcf7693      398.266 +- 21.9733      6      bad
chromium@505210,v8@e1cdda2512      394.498 +- 42.3012      6      bad
chromium@505211                    393.283 +- 27.1904      6      bad
chromium@505214                    382.471 +- 21.487       6      bad
chromium@505238                    389.371 +- 9.84885      6      bad

To Run This Test
  src/tools/perf/run_benchmark -v --browser=release --output-format=chartjson --upload-results --pageset-repeat=1 --also-run-disabled-tests --story-filter=IGN loading.desktop

More information on addressing performance regressions:
  http://g.co/ChromePerformanceRegressions

Debug information about this bisect:
  https://chromeperf.appspot.com/buildbucket_job_status/8966815769233297200


For feedback, file a bug with component Speed>Bisection
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