All graphs for this bug:
  https://chromeperf.appspot.com/group_report?bug_id=768153

(For debugging:) Original alerts at time of bug-filing:
  https://chromeperf.appspot.com/group_report?sid=9e78b0f0e869db59d2f7053de0af5a5aa7e363e0370e0a1b012b24b7fdd954c4


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

chromium-rel-mac12

Started bisect job https://chromeperf.appspot.com/buildbucket_job_status/8967653869144011216

=== Auto-CCing suspected CL author v8-autoroll@chromium.org ===

Hi v8-autoroll@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 : v8-autoroll
  Commit : c089d14822c4827ea48867069fa0446679791b15
  Date   : Thu Sep 21 13:49:53 2017
  Subject: Version 6.3.187

Bisect Details
  Configuration: mac_10_12_perf_bisect
  Benchmark    : speedometer
  Metric       : Total/Total
  Change       : 2.67% | 2909.43658333 -> 2831.90008333

Revision                           Result                  N
chromium@503429                    2909.44 +- 37.2591      6      good
chromium@503472                    2892.73 +- 42.6411      9      good
chromium@503483                    2935.11 +- 52.3742      6      good
chromium@503489                    2910.71 +- 39.6567      6      good
chromium@503491                    2926.76 +- 42.4601      6      good
chromium@503491,v8@a76d0a771e      2917.21 +- 150.936      6      good
chromium@503491,v8@c089d14822      2842.13 +- 40.7928      6      bad       <--
chromium@503492                    2847.83 +- 29.0239      6      bad
chromium@503494                    2842.6 +- 38.6874       6      bad
chromium@503515                    2831.9 +- 68.8747       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 speedometer

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

Debug information about this bisect:
  https://chromeperf.appspot.com/buildbucket_job_status/8967653869144011216


For feedback, file a bug with component Speed>Bisection

Started bisect job https://chromeperf.appspot.com/buildbucket_job_status/8967522451188173440

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

Suspected Commit
  Author : Ulan Degenbaev
  Commit : a76d0a771e430dbc8716624febc549aede738d96
  Date   : Thu Sep 21 12:35:10 2017
  Subject: Reland "[heap] Enable concurrent marking for x86 and x64."

Bisect Details
  Configuration: mac_retina_perf_bisect
  Benchmark    : speedometer
  Metric       : React-TodoMVC/React-TodoMVC
  Change       : 4.32% | 634.044333333 -> 606.643583333

Revision                           Result                  N
chromium@503432                    634.044 +- 12.3729      6      good
chromium@503476                    636.585 +- 31.3438      6      good
chromium@503487                    635.246 +- 12.5383      6      good
chromium@503490                    633.306 +- 11.8246      6      good
chromium@503491                    632.065 +- 16.9627      6      good
chromium@503491,v8@2857dab5cb      624.785 +- 19.6519      6      good
chromium@503491,v8@a76d0a771e      605.195 +- 13.8445      6      bad       <--
chromium@503492                    601.576 +- 15.1986      6      bad
chromium@503493                    607.446 +- 13.3772      6      bad
chromium@503498                    607.79 +- 31.7716       9      bad
chromium@503520                    606.644 +- 23.1375      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 speedometer

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

Debug information about this bisect:
  https://chromeperf.appspot.com/buildbucket_job_status/8967522451188173440


For feedback, file a bug with component Speed>Bisection