All graphs for this bug:
  https://chromeperf.appspot.com/group_report?bug_id=623065

Original alerts at time of bug-filing:
  https://chromeperf.appspot.com/group_report?keys=agxzfmNocm9tZXBlcmZyFAsSB0Fub21hbHkYgICgwo_IrQoM,agxzfmNocm9tZXBlcmZyFAsSB0Fub21hbHkYgICgwpmSvAoM,agxzfmNocm9tZXBlcmZyFAsSB0Fub21hbHkYgICgoqTKqAoM,agxzfmNocm9tZXBlcmZyFAsSB0Fub21hbHkYgICgorDJtAoM


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

chromium-rel-mac-retina

=== 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 : 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 complaints, we may inhibit
the switch based on what kind of content was rendered to the canvas.

BUG= 606688 

Review-Url: https://codereview.chromium.org/2063473002
Cr-Commit-Position: refs/heads/master@{#401751}
Commit  : 33732aec33c88cb18c212544da7d0a4ba53cd9ce
Date    : Thu Jun 23 23:22:04 2016


===== TESTED REVISIONS =====
Revision         Mean     Std Dev  N  Good?
chromium@401735  891.488  46.3594  5  good
chromium@401744  823.723  87.6589  5  good
chromium@401749  870.0    95.5338  5  good
chromium@401750  878.126  39.488   5  good
chromium@401751  452.247  1.27148  5  bad    <--
chromium@401753  449.322  3.28432  5  bad

Bisect job ran on: mac_retina_perf_bisect
Bug ID: 623065

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: 49.60%
Score: 99.9

Buildbot stdio: http://build.chromium.org/p/tryserver.chromium.perf/builders/mac_retina_perf_bisect/builds/1356
Job details: https://chromeperf.appspot.com/buildbucket_job_status/9008963591976522352


Not what you expected? We'll investigate and get back to you!
  https://chromeperf.appspot.com/bad_bisect?try_job_id=5249767924301824

| 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!

Moving this nonessential bug to the next milestone.

For more details visit https://www.chromium.org/issue-tracking/autotriage - Your friendly Sheriffbot

junov@ - Ping!

junov, looks like your patch caused a regression. Can you take a look?

The test result are back to normal now.
Was taken care of by chromium.googlesource.com/chromium/src/+/f0fad4a76fcb3105f871ad93311a13cd83cd6bd8