All graphs for this bug:
  https://chromeperf.appspot.com/group_report?bug_id=751639

(For debugging:) Original alerts at time of bug-filing:
  https://chromeperf.appspot.com/group_report?sid=792270948d539a65ead40c6c0e82054a98dc8466aef212450163aa005e5c0b6a


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

chromium-rel-win7-gpu-intel
chromium-rel-win8-dual

Started bisect job https://chromeperf.appspot.com/buildbucket_job_status/8972368039540198704

Started bisect job https://chromeperf.appspot.com/buildbucket_job_status/8972367974681842240

Kicked off a second bisect on a wider revision range.

=== BISECT JOB RESULTS ===
Bisect failed unexpectedly

Bisect was aborted with the following:
  Step('Check bisect finished on revision chromium@490403,skia@f7928b4f33.fetch file f7928b4f33b5e899b4ac543d8d850523cbd1d6da:DEPS') failed with return_code 1


Bisect Details
  Configuration: win_8_perf_bisect
  Benchmark    : thread_times.tough_scrolling_cases
  Metric       : thread_raster_cpu_time_per_frame/text_constant_full_page_raster_40000_pixels_per_second

Revision                             Result                    N
chromium@490325                      2.43458 +- 0.155467       14      good
chromium@490386                      2.44499 +- 0.162051       14      good
chromium@490401                      2.37598 +- 0.0534242      6       good
chromium@490403                      2.36971 +- 0.178548       9       good
chromium@490403,skia@f7928b4f33      2.44891 +- 0.229359       14      good
chromium@490404                      2.53921 +- 0.159367       9       bad
chromium@490405                      2.58487 +- 0.147525       6       bad
chromium@490409                      2.50729 +- 0.145242       6       bad
chromium@490418                      2.53222 +- 0.144098       6       bad
chromium@490447                      2.51001 +- 0.195218       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=text.constant.full.page.raster.40000.pixels.per.second thread_times.tough_scrolling_cases

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

Debug information about this bisect:
  https://chromeperf.appspot.com/buildbucket_job_status/8972368039540198704


For feedback, file a bug with component Speed>Bisection

=== BISECT JOB RESULTS ===
NO Perf regression found, tests failed to produce values

Bisect Details
  Configuration: win_8_perf_bisect
  Benchmark    : thread_times.tough_scrolling_cases
  Metric       : thread_raster_cpu_time_per_frame/text_constant_full_page_raster_40000_pixels_per_second

Revision             Result                   N
chromium@489984      2.38618 +- 0.211605      21      good

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=text.constant.full.page.raster.40000.pixels.per.second thread_times.tough_scrolling_cases

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

Debug information about this bisect:
  https://chromeperf.appspot.com/buildbucket_job_status/8972367974681842240


For feedback, file a bug with component Speed>Bisection

Started bisect job https://chromeperf.appspot.com/buildbucket_job_status/8970614148264035584

Kicked off a bisect on a wider range, not sure if the test is stable enough to produce values though.

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

Suspected Commit
  Author : Hans Wennborg
  Commit : d2c91228a51bdf37ae3b2e501fb53c0528f1629c
  Date   : Fri Jul 28 20:11:05 2017
  Subject: win: Set is_clang=true by default

Bisect Details
  Configuration: winx64intel_perf_bisect
  Benchmark    : thread_times.tough_scrolling_cases
  Metric       : thread_raster_cpu_time_per_frame/text_constant_full_page_raster_40000_pixels_per_second
  Change       : 6.56% | 3.66834709188 -> 3.90903214171

Revision             Result                    N
chromium@490187      3.66835 +- 0.179242       6      good
chromium@490416      3.51667 +- 0.203926       6      good
chromium@490473      3.57708 +- 0.150276       6      good
chromium@490488      3.51974 +- 0.0645699      6      good
chromium@490492      3.5226 +- 0.126191        6      good
chromium@490493      3.52475 +- 0.11674        6      good
chromium@490494      3.96586 +- 0.106579       6      bad       <--
chromium@490495      3.99896 +- 0.122475       6      bad
chromium@490502      3.9184 +- 0.103029        6      bad
chromium@490530      3.91839 +- 0.101362       6      bad
chromium@490644      3.90903 +- 0.175783       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=text.constant.full.page.raster.40000.pixels.per.second thread_times.tough_scrolling_cases

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

Debug information about this bisect:
  https://chromeperf.appspot.com/buildbucket_job_status/8970614148264035584


For feedback, file a bug with component Speed>Bisection