All graphs for this bug:
  https://chromeperf.appspot.com/group_report?bug_id=741725

(For debugging:) Original alerts at time of bug-filing:
  https://chromeperf.appspot.com/group_report?sid=754bb2728afa0d346db654f48b574ac7f1dd00d12cd26f472510b512c4daaf21


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

chromium-rel-win7-gpu-intel

Started bisect job https://chromeperf.appspot.com/buildbucket_job_status/8974256468033148240

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

Hi junov@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 : Justin Novosad
  Commit : 3750a7881ce851e03ce6177dca30307eb4a7f5c6
  Date   : Mon Jul 10 20:50:59 2017
  Subject: Disabling display list 2D canvas by default

Bisect Details
  Configuration: winx64intel_perf_bisect
  Benchmark    : smoothness.gpu_rasterization.tough_path_rendering_cases
  Metric       : frame_times/MotionMark Canvas Stroke Shapes
  Change       : 77.96% | 16.795869452 -> 29.8892924365

Revision             Result                   N
chromium@485332      16.7959 +- 0.30306       6      good
chromium@485362      16.8577 +- 0.254555      6      good
chromium@485370      16.9437 +- 0.462336      6      good
chromium@485371      29.7545 +- 0.321784      6      bad       <--
chromium@485372      29.9967 +- 1.01612       6      bad
chromium@485374      30.0998 +- 0.259233      6      bad
chromium@485377      30.3004 +- 0.745431      6      bad
chromium@485392      29.9505 +- 0.585215      6      bad
chromium@485452      29.8893 +- 0.26637       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=MotionMark.Canvas.Stroke.Shapes smoothness.gpu_rasterization.tough_path_rendering_cases

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

Debug information about this bisect:
  https://chromeperf.appspot.com/buildbucket_job_status/8974256468033148240


For feedback, file a bug with component Speed>Bisection

 Issue 741726  has been merged into this issue.

 Issue 742095  has been merged into this issue.

This seems a bit odd. Display list 2D canvas should have only kicked in for canvases that were software rendered, but the "Stroke Shapes" uses a single large canvas which should always be GPU accelerated and never trigger display list 2D canvas in the first place. At any rate, if it was rasterized in software, it does mean we lose the parallelism we gained from rendering into multiple tiles on separate threads, so it's logical that it should run slower with display list 2D canvas disabled.

 Issue 741705  has been merged into this issue.