All graphs for this bug:
  https://chromeperf.appspot.com/group_report?bug_id=630670

Original alerts at time of bug-filing:
  https://chromeperf.appspot.com/group_report?keys=agxzfmNocm9tZXBlcmZyFAsSB0Fub21hbHkYgICg2trtsQkM,agxzfmNocm9tZXBlcmZyFAsSB0Fub21hbHkYgICg2tqWvgoM


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

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

Started bisect job https://chromeperf.appspot.com/buildbucket_job_status/9006417767670008784

=== 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 : Re-enable canvas optimization for getImageData with new codepath
Author  : junov
Commit description:
  
This change re-enables the optimization that makes canvases switch
out of gpu-acceleration when getImageData is called.  The old
implementation was scrapped in favor of the new
ImageBuffer::disableAcceleration method that was introduced by
https://crrev.com/98739b054a5b28cc607d688b2e9e582456bbb20e

BUG= 606688 

Review-Url: https://codereview.chromium.org/2171513003
Cr-Commit-Position: refs/heads/master@{#406950}
Commit  : e56410217e3d336d0c2d1dbc442180aefba935c5
Date    : Thu Jul 21 21:27:48 2016


===== TESTED REVISIONS =====
Revision         Mean     Std Dev   N  Good?
chromium@406942  512.277  5.83905   5  good
chromium@406947  507.419  6.47643   5  good
chromium@406949  512.886  3.6784    5  good
chromium@406950  336.694  0.494275  5  bad    <--
chromium@406951  335.609  2.82877   5  bad
chromium@406960  335.758  2.72939   5  bad
chromium@406977  373.846  0.363173  5  bad

Bisect job ran on: mac_10_11_perf_bisect
Bug ID: 630670

Test Command: src/tools/perf/run_benchmark -v --browser=release --output-format=chartjson --upload-results --also-run-disabled-tests blink_perf.canvas
Test Metric: putImageData/putImageData
Relative Change: 27.02%
Score: 99.9

Buildbot stdio: http://build.chromium.org/p/tryserver.chromium.perf/builders/mac_10_11_perf_bisect/builds/755
Job details: https://chromeperf.appspot.com/buildbucket_job_status/9006417767670008784


Not what you expected? We'll investigate and get back to you!
  https://chromeperf.appspot.com/bad_bisect?try_job_id=5878703389671424

| 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!

Friendly perf-sheriff ping, could your patch have caused this regression?

The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/c3a213e577d12c648fce456d2e0098fe36194abd

commit c3a213e577d12c648fce456d2e0098fe36194abd
Author: junov <junov@chromium.org>
Date: Tue Aug 02 19:11:14 2016

Fixing regression in putImageData blink perf test

Creating the image data object by using createImageData instead of
getImageData to avoid state changes that interfere with the
benchmark's execution.  Also doing a drive-by code simplification

BUG= 630670 

Review-Url: https://codereview.chromium.org/2190523003
Cr-Commit-Position: refs/heads/master@{#409263}

[modify] https://crrev.com/c3a213e577d12c648fce456d2e0098fe36194abd/third_party/WebKit/PerformanceTests/Canvas/putImageData.html

Graph shows that this was fixed by junov's patch above.

Thanks!