All graphs for this bug:
  https://chromeperf.appspot.com/group_report?bug_id=757342

(For debugging:) Original alerts at time of bug-filing:
  https://chromeperf.appspot.com/group_report?sid=55a9251068bb52fe05dcf6a58ecf6d6b251c78cded03af9768ec03499235a6e1


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

chromium-rel-win10
chromium-rel-win7-dual
chromium-rel-win7-gpu-nvidia
chromium-rel-win8-dual

Started bisect job https://chromeperf.appspot.com/buildbucket_job_status/8970675327779890768

=== Auto-CCing suspected CL author thakis@chromium.org ===

Hi thakis@chromium.org, the bisect results pointed to your CL, please take a look at the
results.


=== 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_perf_bisect
  Benchmark    : media_perftests
  Metric       : audio_bus_from_interleaved/int8_t
  Change       : 21.52% | 12.5381166667 -> 15.2358166667

Revision             Result                    N
chromium@495791      12.5381 +- 0.0269059      6      good
chromium@495800      12.5248 +- 0.0543778      6      good
chromium@495801      12.5406 +- 0.0573158      6      good
chromium@495802      15.291 +- 0.0653038       6      bad       <--
chromium@495804      15.2463 +- 0.0657997      6      bad
chromium@495808      15.2358 +- 0.0770166      6      bad

To Run This Test
  .\src\out\Release\media_perftests.exe --single-process-tests

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

Debug information about this bisect:
  https://chromeperf.appspot.com/buildbucket_job_status/8970675327779890768


For feedback, file a bug with component Speed>Bisection

 Issue 757356  has been merged into this issue.

 Issue 757356  has been merged into this issue.

 Issue 757341  has been merged into this issue.

 Issue 757739  has been merged into this issue.

 Issue 757739  has been merged into this issue.

 Issue 757492  has been merged into this issue.

 Issue 757739  has been merged into this issue.

 Issue 757493  has been merged into this issue.

 Issue 757493  has been merged into this issue.

 Issue 757928  has been merged into this issue.

 Issue 758284  has been merged into this issue.

 Issue 758313  has been merged into this issue.

 Issue 758313  has been merged into this issue.

 Issue 758332  has been merged into this issue.

 Issue 758580  has been merged into this issue.

 Issue 758590  has been merged into this issue.

 Issue 758581  has been merged into this issue.

 Issue 758583  has been merged into this issue.

 Issue 758573  has been merged into this issue.

 Issue 758595  has been merged into this issue.

 Issue 758584  has been merged into this issue.

 Issue 758586  has been merged into this issue.

some of the dupes:
5.6% regression in speedometer2 at 495792:495808
2.9%-21.5% regression in v8.runtimestats.browsing_desktop at 495785:495808
6.2%-19.9% regression in v8.browsing_desktop at 495707:495808
51.8% regression in runs/s clockless_playback sfx_u8.wav - media_perftests at 495385:495501
42.9% regression in blink_perf.parser at 495785:495808
10.2% regression in thread_times.tough_scrolling_cases at 495792:495808
12.3% regression in blink_perf.layout at 495794:495808	
12.8% regression in blink_perf.svg at 495794:495808
9.7% regression in smoothness.gpu_rasterization.tough_path_rendering_cases at 495792:495808
15.1% regression in startup.cold.blank_page at 495727:495805
19.2% regression in blink_perf.bindings at 495794:495808
19.9% regression in blink_perf.paint at 495794:495808
14.1% regression in blink_perf.shadow_dom at 495794:495808

 Issue 758599  has been merged into this issue.

 Issue 758693  has been merged into this issue.

 Issue 758911  has been merged into this issue.

 Issue 758912  has been merged into this issue.

 Issue 758978  has been merged into this issue.

 Issue 758962  has been merged into this issue.

14.4% regression in blink_perf.css at 495794:495808
13.1% regression in smoothness.tough_filters_cases at 495792:495808
19.8% regression in memory.desktop at 495785:495808
37.3% regression in rasterize_and_record_micro.top_25 at 495792:495808

 Issue 758951  has been merged into this issue.

5.3% regression in image_decoding.image_decoding_measurement at 495794:495808

 Issue 758947  has been merged into this issue.

 Issue 758977  has been merged into this issue.

4.4% regression in performance_browser_tests at 495801:495808

 Issue 759069  has been merged into this issue.

 Issue 759062  has been merged into this issue.

 Issue 759043  has been merged into this issue.

 Issue 759032  has been merged into this issue.

 Issue 759032  has been merged into this issue.

 Issue 759107  has been merged into this issue.

 Issue 759599  has been merged into this issue.

 Issue 759662  has been merged into this issue.

 Issue 759602  has been merged into this issue.

 Issue 759635  has been merged into this issue.

 Issue 760162  has been merged into this issue.

 Issue 760159  has been merged into this issue.

 Issue 760161  has been merged into this issue.

 Issue 758250  has been merged into this issue.

24.5% regression in system_health.common_desktop at 495792:495808
49.1% regression in clockless runs/sec - media_perftests at 495268:495384
9.7% regression in smoothness.gpu_rasterization.tough_filters_cases at 495792:495808
14.9% regression in smoothness.tough_animation_cases at 495785:495808
10.4% regression in dromaeo.domcoremodify at 495792:495808
10.6% regression in startup.warm.blank_page at 495792:495808
4.7%-11.8% regression in smoothness.tough_canvas_cases at 495792:495808
smoothness.desktop_tough_pinch_zoom_cases failing on 8 builders	

 Issue 757340  has been merged into this issue.

This was caused by reverting the clang switch. We've since relanded it, so this should be better.