All graphs for this bug:
  https://chromeperf.appspot.com/group_report?bug_id=653078

Original alerts at time of bug-filing:
  https://chromeperf.appspot.com/group_report?keys=agxzfmNocm9tZXBlcmZyFAsSB0Fub21hbHkYgICgtanarQoM,agxzfmNocm9tZXBlcmZyFAsSB0Fub21hbHkYgICgtaq3ogsM,agxzfmNocm9tZXBlcmZyFAsSB0Fub21hbHkYgICgtY38sAoM


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/8999640648789841104

Started bisect job https://chromeperf.appspot.com/buildbucket_job_status/8999629261698838432

Added two more alerts to this bug. 
P.S. All alerts seems to be a regression over an earlier improvement but it is not clear to me what is the cause. Hopefully bisect will point it out to us. 

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


=== Bisection aborted ===
The bisect was aborted because The metric values for the initial "good" and "bad" revisions do not represent a clear regression.
Please contact the the team (see below) if you believe this is in error.

=== Warnings ===
The following warnings were raised by the bisect job:

 * Bisect failed to reproduce the regression with enough confidence.

===== TESTED REVISIONS =====
Revision         Mean     Std Dev  N   Good?
chromium@422614  353.514  89.9482  18  good
chromium@422631  336.101  88.6026  18  bad

Bisect job ran on: mac_retina_perf_bisect
Bug ID: 653078

Test Command: src/tools/perf/run_benchmark -v --browser=release --output-format=chartjson --upload-results --also-run-disabled-tests page_cycler_v2.tough_layout_cases
Test Metric: timeToFirstContentfulPaint_avg/pcv1-warm/http___natunkantha.com
Relative Change: 27.41%
Score: 0

Buildbot stdio: http://build.chromium.org/p/tryserver.chromium.perf/builders/mac_retina_perf_bisect/builds/1720
Job details: https://chromeperf.appspot.com/buildbucket_job_status/8999640648789841104


Not what you expected? We'll investigate and get back to you!
  https://chromeperf.appspot.com/bad_bisect?try_job_id=5853892628185088

| 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!

=== 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 cc: Remove frame queuing from the scheduler. (patchset #14 id:400001 of https://codereview.chromium.org/2339633003/ )
Author  : sunnyps
Commit description:
  
Reason for revert:
Highly likely that this is causing the flakes we are seeing in  http://crbug.com/645736 

Original issue's description:
> Reland of cc: Remove frame queuing from the scheduler. (patchset #1 id:1 of https://codereview.chromium.org/2336493002/ )
>
> Reason for revert:
> Reland after fixing screenshot grabber test and perf issues.
>
> Original issue's description:
> > Revert of cc: Remove frame queuing from the scheduler. (patchset #3 id:40001 of https://codereview.chromium.org/2323063004/ )
> >
> > Reason for revert:
> > Broke ChromeScreenshotGrabberTest.TakeScreenshot on  Linux ChromiumOS Tests (dbg)(1): https://build.chromium.org/p/chromium.chromiumos/builders/Linux%20ChromiumOS%20Tests%20%28dbg%29%281%29/builds/18015.
> >
> > Original issue's description:
> > > cc: Remove frame queuing from the scheduler.
> > >
> > > CC scheduler has a frame queuing mechanism called "retro frames". This
> > > has been responsible for a lot of complexity and hard to fix bugs. The
> > > original intent for adding retro frames was to allow the scheduler to
> > > handle multiple frames in flight but that goal doesn't seem feasible or
> > > even desirable any more. This CL removes the retro frames queue and
> > > instead makes the Scheduler end the previous frame when it receives a
> > > BeginFrame message.
> > >
> > > One surprising behavior was that SyntheticBFS MISSED frames would be
> > > queued as retro frames and this would convert the synchronous begin
> > > frame call (inside Scheduler::ProcessScheduledActions) to an
> > > asynchronous retro frame PostTask. To work around this the Scheduler
> > > keeps track of a single CancelableClosure that's used for MISSED frames.
> > >
> > > The above behavior was also causing the BeginFramesNotFromClient tests
> > > to work even though there was an extra MISSED frame in the queue. This
> > > is more elegantly solved in another way by using frame number to advance
> > > the task runner instead of just running pending tasks.
> > >
> > > Lastly SchedulerStateMachine is modified so that it's possible to end
> > > the previous frame and still have the same behavior as before in the
> > > commit to active tree (browser compositor) mode.
> > >
> > > R=brianderson@chromium.org,enne@chromium.org,danakj@chromium.org
> > > BUG= 602485 ,  644992 
> > > CQ_INCLUDE_TRYBOTS=master.tryserver.blink:linux_precise_blink_rel
> > >
> > > Committed: https://crrev.com/559280b26cc5672f5f054e8ac35281e804c14d78
> > > Cr-Commit-Position: refs/heads/master@{#417764}
> >
> > TBR=enne@chromium.org,brianderson@chromium.org,danakj@chromium.org,sunnyps@chromium.org
> > # Not skipping CQ checks because original CL landed more than 1 days ago.
> > BUG= 602485 ,  644992 
> >
> > Committed: https://crrev.com/95beb47e50065959ee2f5b43cf431431e32e14cd
> > Cr-Commit-Position: refs/heads/master@{#417895}
>
> TBR=enne@chromium.org,brianderson@chromium.org,danakj@chromium.org,sammc@chromium.org
> # Not skipping CQ checks because original CL landed more than 1 days ago.
> BUG= 602485 ,  644992 
> CQ_INCLUDE_TRYBOTS=master.tryserver.blink:linux_precise_blink_rel
>
> Committed: https://crrev.com/864a70f6f93a87ff374bf2aea2494d4d7d0150d7
> Cr-Commit-Position: refs/heads/master@{#421268}

TBR=enne@chromium.org,danakj@chromium.org,brianderson@chromium.org
BUG= 602485 ,  644992 
CQ_INCLUDE_TRYBOTS=master.tryserver.blink:linux_precise_blink_rel

Review-Url: https://codereview.chromium.org/2386183003
Cr-Commit-Position: refs/heads/master@{#422595}
Commit  : 5a28cd7dd0ac324e02428174ed3333dbe88edfcd
Date    : Mon Oct 03 23:32:22 2016


===== TESTED REVISIONS =====
Revision         Mean     Std Dev  N  Good?
chromium@422580  152.601  4.13914  8  good
chromium@422594  154.019  5.49023  8  good
chromium@422595  171.486  10.4041  5  bad    <--
chromium@422596  172.416  10.623   8  bad
chromium@422598  173.047  7.33923  5  bad
chromium@422601  172.094  8.7172   5  bad
chromium@422607  174.626  9.1703   8  bad

Bisect job ran on: mac_10_11_perf_bisect
Bug ID: 653078

Test Command: src/tools/perf/run_benchmark -v --browser=release --output-format=chartjson --upload-results --also-run-disabled-tests page_cycler_v2.intl_ko_th_vi
Test Metric: timeToFirstMeaningfulPaint_avg/pcv1-warm/http___us.24h.com.vn_
Relative Change: 12.09%
Score: 99.8

Buildbot stdio: http://build.chromium.org/p/tryserver.chromium.perf/builders/mac_10_11_perf_bisect/builds/945
Job details: https://chromeperf.appspot.com/buildbucket_job_status/8999629261698838432


Not what you expected? We'll investigate and get back to you!
  https://chromeperf.appspot.com/bad_bisect?try_job_id=6096143883173888

| 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!

This has recovered.