All graphs for this bug:
  https://chromeperf.appspot.com/group_report?bug_id=768290

(For debugging:) Original alerts at time of bug-filing:
  https://chromeperf.appspot.com/group_report?sid=346cc1a7283a19d4f3651869b81947cab8b79f9ef2779da60714aaa0c1681d12


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

chromium-rel-mac11-air
chromium-rel-mac12-mini-8gb
chromium-rel-win7-dual
chromium-rel-win7-gpu-intel
chromium-rel-win7-x64-dual
chromium-rel-win8-dual

Started bisect job https://chromeperf.appspot.com/buildbucket_job_status/8967498874719073424

=== 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    : v8.browsing_desktop
  Metric       : v8-gc-total_avg/browse_media/browse_media_imgur
  Change       : 286.54% | 1.14411104447 -> 4.42241302195

Revision                           Result                   N
chromium@503453                    1.14411 +- 0.342454      6      good
chromium@503483                    1.14891 +- 0.28489       6      good
chromium@503491                    1.09747 +- 0.378469      6      good
chromium@503491,v8@2857dab5cb      1.35318 +- 0.288465      6      good
chromium@503491,v8@a76d0a771e      5.22565 +- 1.51082       6      bad       <--
chromium@503492                    4.98687 +- 1.79212       6      bad
chromium@503493                    4.66348 +- 1.83246       6      bad
chromium@503495                    4.90515 +- 2.01374       6      bad
chromium@503498                    4.60882 +- 1.92371       6      bad
chromium@503513                    4.9923 +- 1.11668        6      bad
chromium@503572                    4.42241 +- 2.63099       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=browse.media.imgur v8.browsing_desktop

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

Debug information about this bisect:
  https://chromeperf.appspot.com/buildbucket_job_status/8967498874719073424


For feedback, file a bug with component Speed>Bisection