All graphs for this bug:
  https://chromeperf.appspot.com/group_report?bug_id=757492

(For debugging:) Original alerts at time of bug-filing:
  https://chromeperf.appspot.com/group_report?sid=35686a54c54eb152d5f8488075bd23f29ee754cf90b7b2e2a75e7633cc4aa945


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

chromium-rel-win7-dual
chromium-rel-win7-gpu-nvidia
chromium-rel-win7-x64-dual
chromium-rel-win8-dual

Started bisect job https://chromeperf.appspot.com/buildbucket_job_status/8970632264560207920

=== BISECT JOB RESULTS ===
Perf regression found but unable to narrow commit range

Build failures prevented the bisect from narrowing the range further.


Bisect Details
  Configuration: win_8_perf_bisect
  Benchmark    : v8.runtimestats.browsing_desktop
  Metric       : v8-gc-incremental-step_sum/browse_search/browse_search_google
  Change       : 14.53% | 63.7722857143 -> 69.1001428571

Suspected Commit Range
  2 commits in range
  https://chromium.googlesource.com/chromium/src/+log/91044a7378737cd78dcd5207d779a4a014179fd7..bfdb476db13c2bd4d62aadda3f0eba6996ab3ba4


Revision             Result                  N
chromium@495787      63.7723 +- 16.3864      14       good
chromium@495797      65.3564 +- 13.7147      14       good
chromium@495798      ---                     ---      build failure
chromium@495799      67.353 +- 32.3293       21       bad
chromium@495800      69.6257 +- 34.5315      14       bad
chromium@495801      72.2819 +- 35.8083      14       bad
chromium@495803      71.8614 +- 24.5849      9        bad
chromium@495808      69.1001 +- 43.2922      14       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.search.google v8.runtimestats.browsing_desktop

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

Debug information about this bisect:
  https://chromeperf.appspot.com/buildbucket_job_status/8970632264560207920


For feedback, file a bug with component Speed>Bisection

Started bisect job https://chromeperf.appspot.com/buildbucket_job_status/8970555305935323024

Started bisect job https://chromeperf.appspot.com/buildbucket_job_status/8970555288620321504

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

Suspected Commit
  Author : Nico Weber
  Commit : 7cd2f6bd73c6a9c6200704e995b18ebb3168ead6
  Date   : Sat Aug 19 04:23:54 2017
  Subject: win: Turn off clang-by-default again for now.

Bisect Details
  Configuration: win_x64_perf_bisect
  Benchmark    : v8.runtimestats.browsing_desktop
  Metric       : v8-gc-full-mark-compactor_avg/browse_media/browse_media_imgur
  Change       : 6.95% | 50.0829235195 -> 53.5652877706

Revision             Result                  N
chromium@495800      50.0829 +- 1.22165      6      good
chromium@495801      50.4267 +- 1.39097      6      good
chromium@495802      53.6673 +- 1.5809       6      bad       <--
chromium@495804      53.2957 +- 1.78298      6      bad
chromium@495808      53.5653 +- 1.26645      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 --story-filter=browse.media.imgur v8.runtimestats.browsing_desktop

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

Debug information about this bisect:
  https://chromeperf.appspot.com/buildbucket_job_status/8970555305935323024


For feedback, file a bug with component Speed>Bisection

=== BISECT JOB RESULTS ===
NO Perf regression found

Bisect Details
  Configuration: win_perf_bisect
  Benchmark    : v8.runtimestats.browsing_desktop
  Metric       : v8-gc-full-mark-compactor_avg/browse_search/browse_search_google

Revision             Result                  N
chromium@495791      14.967 +- 33.9457       20      good
chromium@495808      14.5659 +- 29.9977      20      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.search.google v8.runtimestats.browsing_desktop

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

Debug information about this bisect:
  https://chromeperf.appspot.com/buildbucket_job_status/8970555288620321504


For feedback, file a bug with component Speed>Bisection