All graphs for this bug:
  https://chromeperf.appspot.com/group_report?bug_id=626032

Original alerts at time of bug-filing:
  https://chromeperf.appspot.com/group_report?keys=agxzfmNocm9tZXBlcmZyFAsSB0Fub21hbHkYgICg0qvd6woM,agxzfmNocm9tZXBlcmZyFAsSB0Fub21hbHkYgICg0ta0ugoM,agxzfmNocm9tZXBlcmZyFAsSB0Fub21hbHkYgICg0tKupQkM,agxzfmNocm9tZXBlcmZyFAsSB0Fub21hbHkYgICg0s_csgoM,agxzfmNocm9tZXBlcmZyFAsSB0Fub21hbHkYgICg0p3RtgoM,agxzfmNocm9tZXBlcmZyFAsSB0Fub21hbHkYgICg0sy7ogkM,agxzfmNocm9tZXBlcmZyFAsSB0Fub21hbHkYgICg0uuzsQoM,agxzfmNocm9tZXBlcmZyFAsSB0Fub21hbHkYgICg0vDbqQoM,agxzfmNocm9tZXBlcmZyFAsSB0Fub21hbHkYgICg0p3GpwoM,agxzfmNocm9tZXBlcmZyFAsSB0Fub21hbHkYgICg0qzUqgoM,agxzfmNocm9tZXBlcmZyFAsSB0Fub21hbHkYgICg0p2oqwoM,agxzfmNocm9tZXBlcmZyFAsSB0Fub21hbHkYgICgkuv3ugkM,agxzfmNocm9tZXBlcmZyFAsSB0Fub21hbHkYgICg0obnvgkM,agxzfmNocm9tZXBlcmZyFAsSB0Fub21hbHkYgICg0vCxoQoM


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

chromium-rel-mac-retina
chromium-rel-mac10
chromium-rel-mac11

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

Hi junov@chromium.org, the bisect results pointed to your CL below as possibly
causing a regression. Please have a look at this info and see whether
your CL be related.


===== BISECT JOB RESULTS =====
Status: completed


===== SUSPECTED CL(s) =====
Subject : Reland: Make 2D canvas disable gpu acceleration when getImageData is called
Author  : junov
Commit description:
  
In order to optimize performance, GPU-accelerated canvases should
permanently switch out of accalerated mode as soon as
getImageData is called.  The cost of getImageData on the GPU is
so prohibitively high that it almost always outways the benefit
of acceleration.

This is the first time we implement a SW/GPU switch that can happen
after the first frame was presented, which may result in a small one
time glitch due to rendering engine discrepancies. Let's see if we get
any complaints about this.  If there are complaint, we may inhibit
the switch based on what kind of content was rendered to the canvas.

BUG= 606688 

Review-Url: https://codereview.chromium.org/2123623002
Cr-Commit-Position: refs/heads/master@{#403806}
Commit  : 627ddfd0de197d67567a15191f654b8835408bce
Date    : Tue Jul 05 18:29:57 2016


===== TESTED REVISIONS =====
Revision         Mean     Std Dev  N  Good?
chromium@403805  2443.67  67.2373  5  good
chromium@403806  2242.32  28.3576  5  bad    <--
chromium@403807  2177.58  84.3239  5  bad
chromium@403808  2165.24  70.6239  5  bad
chromium@403811  2193.95  67.8029  5  bad

Bisect job ran on: mac_retina_perf_bisect
Bug ID: 626032

Test Command: src/tools/perf/run_benchmark -v --browser=release --output-format=chartjson --upload-results --also-run-disabled-tests blink_perf.canvas
Test Metric: draw-video-to-hw-accelerated-canvas-2d/draw-video-to-hw-accelerated-canvas-2d
Relative Change: 10.22%
Score: 99.9

Buildbot stdio: http://build.chromium.org/p/tryserver.chromium.perf/builders/mac_retina_perf_bisect/builds/1391
Job details: https://chromeperf.appspot.com/buildbucket_job_status/9007870493879216528


Not what you expected? We'll investigate and get back to you!
  https://chromeperf.appspot.com/bad_bisect?try_job_id=4999678723096576

| O O | Visit http://www.chromium.org/developers/speed-infra/perf-bug-faq
|  X  | for more information addressing perf regression bugs. For feedback,
| / \ | file a bug with component Tests>AutoBisect.  Thank you!

junov, was this effect on blink_perf.canvas on mac expected?

Should recover after r404160 Let's wait and see...

Looks like the graph has recovered in the Chromium Commit Position range: 403952 - 404179