All graphs for this bug:
  https://chromeperf.appspot.com/group_report?bug_id=624242

Original alerts at time of bug-filing:
  https://chromeperf.appspot.com/group_report?keys=agxzfmNocm9tZXBlcmZyFAsSB0Fub21hbHkYgICg4tCcuAkM,agxzfmNocm9tZXBlcmZyFAsSB0Fub21hbHkYgICg4vHEuQkM,agxzfmNocm9tZXBlcmZyFAsSB0Fub21hbHkYgICg4sSppAkM,agxzfmNocm9tZXBlcmZyFAsSB0Fub21hbHkYgICg4vHnogoM,agxzfmNocm9tZXBlcmZyFAsSB0Fub21hbHkYgICg4rWmvQkM


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

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

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

Hi sunnyps@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 : Revert of Make 2D canvas disable gpu acceleration when getImageData is called (patchset #6 id:100001 of https://codereview.chromium.org/2063473002/ )
Author  : sunnyps
Commit description:
  
Reason for revert:
Causing crash in mailbox release callback - bug 623101

Original issue's description:
> Make 2D canvas disable gpu acceleration when getImageData is called
>
> 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 
>
> Committed: https://crrev.com/33732aec33c88cb18c212544da7d0a4ba53cd9ce
> Cr-Commit-Position: refs/heads/master@{#401751}

TBR=xlai@chromium.org,xidachen@chromium.org,junov@chromium.org
# Not skipping CQ checks because original CL landed more than 1 days ago.
BUG= 606688 , 623101

Review-Url: https://codereview.chromium.org/2101823002
Cr-Commit-Position: refs/heads/master@{#402391}
Commit  : 27543ee6015a5d358e3abdb6ffb6121f6c847e31
Date    : Tue Jun 28 03:43:13 2016


===== TESTED REVISIONS =====
Revision         Mean     Std Dev   N  Good?
chromium@402383  167.686  0.861815  5  good
chromium@402388  163.683  2.16143   5  good
chromium@402390  163.796  0.229795  5  good
chromium@402391  124.838  0.851199  5  bad    <--
chromium@402393  123.632  2.67882   5  bad
chromium@402402  125.949  3.11469   5  bad

Bisect job ran on: mac_10_11_perf_bisect
Bug ID: 624242

Test Command: src/tools/perf/run_benchmark -v --browser=release --output-format=chartjson --upload-results --also-run-disabled-tests blink_perf.canvas
Test Metric: getImageData/getImageData
Relative Change: 24.89%
Score: 99.9

Buildbot stdio: http://build.chromium.org/p/tryserver.chromium.perf/builders/mac_10_11_perf_bisect/builds/703
Job details: https://chromeperf.appspot.com/buildbucket_job_status/9008557257854205808


Not what you expected? We'll investigate and get back to you!
  https://chromeperf.appspot.com/bad_bisect?try_job_id=5858785764048896

| 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

Not really a regression, the original CL improved performance and was reverted because it caused crashes.