All graphs for this bug:
  https://chromeperf.appspot.com/group_report?bug_id=768067

(For debugging:) Original alerts at time of bug-filing:
  https://chromeperf.appspot.com/group_report?sid=163d94b1570a38bf9167c6b500ebc44d24eb7c16d962511b4e0cb95e90136a9a


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

chromium-rel-mac11-air

Started bisect job https://chromeperf.appspot.com/buildbucket_job_status/8966721649663305264

Started bisect job https://chromeperf.appspot.com/buildbucket_job_status/8966721639849258112

There was no bisect so I started one.

=== 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_10_11_perf_bisect
  Benchmark    : thread_times.tough_compositor_cases
  Metric       : thread_other_cpu_time_per_frame/thread_other_cpu_time_per_frame
  Change       : 116.24% | 0.0301889995773 -> 0.0652819969887

Revision                           Result                       N
chromium@503421                    0.030189 +- 0.00853846       6      good
chromium@503458                    0.034164 +- 0.00825234       6      good
chromium@503476                    0.0330863 +- 0.00921422      6      good
chromium@503485                    0.0305619 +- 0.012367        6      good
chromium@503490                    0.0338768 +- 0.00941856      6      good
chromium@503491                    0.0313159 +- 0.0106285       6      good
chromium@503491,v8@2857dab5cb      0.0317102 +- 0.0069171       6      good
chromium@503491,v8@a76d0a771e      0.064322 +- 0.00882219       6      bad       <--
chromium@503492                    0.0638168 +- 0.00853713      6      bad
chromium@503494                    0.065282 +- 0.00676987       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 thread_times.tough_compositor_cases

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

Debug information about this bisect:
  https://chromeperf.appspot.com/buildbucket_job_status/8966721649663305264


For feedback, file a bug with component Speed>Bisection

=== 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_10_12_mini_8gb_perf_bisect
  Benchmark    : thread_times.tough_compositor_cases
  Metric       : thread_other_cpu_time_per_frame/thread_other_cpu_time_per_frame
  Change       : 129.05% | 0.0247853047493 -> 0.0567714561301

Revision                           Result                       N
chromium@503453                    0.0247853 +- 0.0219592       6      good
chromium@503483                    0.0300813 +- 0.00948684      6      good
chromium@503491                    0.0289803 +- 0.0080887       6      good
chromium@503491,v8@2857dab5cb      0.0301463 +- 0.00864279      6      good
chromium@503491,v8@a76d0a771e      0.0523328 +- 0.00955344      6      bad       <--
chromium@503492                    0.0822976 +- 0.148357        6      bad
chromium@503493                    0.0572593 +- 0.00800148      6      bad
chromium@503495                    0.0573772 +- 0.00689879      6      bad
chromium@503498                    0.0541528 +- 0.0164084       6      bad
chromium@503513                    0.05499 +- 0.0139253         6      bad
chromium@503572                    0.0567715 +- 0.00543695      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 thread_times.tough_compositor_cases

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

Debug information about this bisect:
  https://chromeperf.appspot.com/buildbucket_job_status/8966721639849258112


For feedback, file a bug with component Speed>Bisection