All graphs for this bug:
  https://chromeperf.appspot.com/group_report?bug_id=752418

(For debugging:) Original alerts at time of bug-filing:
  https://chromeperf.appspot.com/group_report?sid=cc56fb4340a497e3b1666b5b86af7e9624e6051795110fe48a1c42e73008ce96


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

chromium-rel-win7-gpu-ati
chromium-rel-win7-gpu-intel
chromium-rel-win7-gpu-nvidia

Started bisect job https://chromeperf.appspot.com/buildbucket_job_status/8972207370475485872

=== Auto-CCing suspected CL author ulan@chromium.org ===

Hi ulan@chromium.org, the bisect results pointed to your CL, please take a look at the
results.


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

Suspected Commit
  Author : Ulan Degenbaev
  Commit : 2cc8fdfb47226101b958da465d64803368fb7c76
  Date   : Thu Jul 27 11:09:24 2017
  Subject: [heap] Re-implement weak cell tracking in the marker.

Bisect Details
  Configuration: winx64intel_perf_bisect
  Benchmark    : memory.long_running_idle_gmail_tbmv2
  Metric       : v8-gc-incremental-finalize_avg/v8-gc-incremental-finalize_avg
  Change       : 85.38% | 1.85032678571 -> 0.270445833333

Revision                           Result                    N
chromium@490004                    1.85033 +- 0.820529       6      good
chromium@490020                    1.85179 +- 1.06694        6      good
chromium@490024                    2.06173 +- 0.674353       6      good
chromium@490026                    1.99243 +- 1.50344        6      good
chromium@490027                    2.04854 +- 0.818227       6      good
chromium@490027,v8@2cc8fdfb47      0.14425 +- 0.206086       6      bad       <--
chromium@490027,v8@6a75fcd4df      0.159454 +- 0.26591       6      bad
chromium@490027,v8@e4bbf92be3      0.208586 +- 0.378123      6      bad
chromium@490027,v8@9836cdb1ad      0.134288 +- 0.139019      6      bad
chromium@490028                    0.1554 +- 0.277611        6      bad
chromium@490036                    0.134562 +- 0.143427      6      bad
chromium@490067                    0.270446 +- 0.441338      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_tbmv2

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

Debug information about this bisect:
  https://chromeperf.appspot.com/buildbucket_job_status/8972207370475485872


For feedback, file a bug with component Speed>Bisection

This is an improvement.