All graphs for this bug:
  https://chromeperf.appspot.com/group_report?bug_id=753981

(For debugging:) Original alerts at time of bug-filing:
  https://chromeperf.appspot.com/group_report?sid=b3d65a0568c8b55479fe2a6de7ad52df95d38aed3a2c039ddfc3e5dfbab99897


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

android-nexus6
chromium-rel-mac-retina
chromium-rel-mac11
chromium-rel-mac11-pro
chromium-rel-mac12
chromium-rel-win10
chromium-rel-win7-gpu-intel
chromium-rel-win7-gpu-nvidia

Started bisect job https://chromeperf.appspot.com/buildbucket_job_status/8971703386208001904

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

Suspected Commit
  Author : Ulan Degenbaev
  Commit : feb3ee40d03137ffcc2be98a01f6ea936cdf45e1
  Date   : Mon Aug 07 16:21:24 2017
  Subject: [heap] Disable parallel scavenge.

Bisect Details
  Configuration: winx64intel_perf_bisect
  Benchmark    : memory.long_running_idle_gmail_background_tbmv2
  Metric       : v8-gc-scavenger_max/v8-gc-scavenger_max
  Change       : 217.55% | 4.472 -> 14.2006666667

Revision                           Result                  N
chromium@492380                    4.472 +- 1.95182        6      good
chromium@492423                    4.61233 +- 2.54351      6      good
chromium@492434                    4.25483 +- 3.73245      6      good
chromium@492440                    4.57217 +- 3.59409      6      good
chromium@492443                    4.5738 +- 2.97068       5      good
chromium@492444                    4.72533 +- 1.2048       6      good
chromium@492444,v8@a7a166e30c      3.92967 +- 2.78926      6      good
chromium@492444,v8@ceb55494bd      3.44717 +- 2.4104       6      good
chromium@492444,v8@feb3ee40d0      13.083 +- 3.18651       6      bad       <--
chromium@492444,v8@864837ff3c      12.3898 +- 4.05441      6      bad
chromium@492445                    12.175 +- 4.34374       6      bad
chromium@492466                    14.2007 +- 3.71424      6      bad

To Run This Test
  src/tools/perf/run_benchmark -v --browser=release_x64 --output-format=chartjson --upload-results --pageset-repeat=1 --also-run-disabled-tests memory.long_running_idle_gmail_background_tbmv2

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

Debug information about this bisect:
  https://chromeperf.appspot.com/buildbucket_job_status/8971703386208001904


For feedback, file a bug with component Speed>Bisection