All graphs for this bug:
  https://chromeperf.appspot.com/group_report?bug_id=778595

(For debugging:) Original alerts at time of bug-filing:
  https://chromeperf.appspot.com/group_report?sid=d7b54b33995838adb918b179f8c72b8ae313b421b4cb71add13aaf7df276cbe5


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

chromium-rel-win10

Started bisect job https://chromeperf.appspot.com/buildbucket_job_status/8964677669317942016

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

Suspected Commit
  Author : Hans Wennborg
  Commit : 22525134c75ca2a005997a717f6887a23af86210
  Date   : Mon Oct 23 17:10:25 2017
  Subject: win: Re-enable Clang by default

Bisect Details
  Configuration: winx64_10_perf_bisect
  Benchmark    : blink_perf.css
  Metric       : PseudoClassSelectors/PseudoClassSelectors
  Change       : 18.23% | 5610.88958263 -> 4587.77363274

Revision             Result                  N
chromium@510768      5610.89 +- 27.2533      6      good
chromium@510798      5456.0 +- 75.8058       6      good
chromium@510813      5447.34 +- 18.1082      6      good
chromium@510821      5557.82 +- 52.9251      6      good
chromium@510823      5501.75 +- 47.5731      6      good
chromium@510824      4577.53 +- 210.461      6      bad       <--
chromium@510825      4544.27 +- 48.4346      6      bad
chromium@510828      4587.77 +- 284.296      6      bad

Please refer to the following doc on diagnosing blink_perf regressions:
  https://chromium.googlesource.com/chromium/src/+/master/docs/speed/benchmark_harnesses/blink_perf.md

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 blink_perf.css

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

Debug information about this bisect:
  https://chromeperf.appspot.com/buildbucket_job_status/8964677669317942016


For feedback, file a bug with component Speed>Bisection