All graphs for this bug:
  https://chromeperf.appspot.com/group_report?bug_id=626639

Original alerts at time of bug-filing:
  https://chromeperf.appspot.com/group_report?keys=agxzfmNocm9tZXBlcmZyFAsSB0Fub21hbHkYgICg0rOAugoM,agxzfmNocm9tZXBlcmZyFAsSB0Fub21hbHkYgICgsqWluQoM,agxzfmNocm9tZXBlcmZyFAsSB0Fub21hbHkYgICgstzRvQoM


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

android-nexus5X
android-nexus6

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

Hi rockot@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 Mojo-based waiting for IPC::SyncChannel
Author  : rockot
Commit description:
  
BUG=612500
TBR=jam@chromium.org

Review-Url: https://codereview.chromium.org/2101163002
Cr-Commit-Position: refs/heads/master@{#404233}
Commit  : 3c23629163a036c17017c4c2d16a0ac77f62d469
Date    : Thu Jul 07 20:27:22 2016


===== TESTED REVISIONS =====
Revision         Mean     Std Dev     N  Good?
chromium@404209  1.67459  0.0278545   5  good
chromium@404222  1.69139  0.0106449   5  good
chromium@404229  1.68194  0.0126349   5  good
chromium@404232  1.6723   0.00722294  5  good
chromium@404233  1.79021  0.0207351   5  bad    <--
chromium@404234  1.78778  0.0148835   5  bad
chromium@404235  1.78092  0.00886659  5  bad

Bisect job ran on: android_nexus6_perf_bisect
Bug ID: 626639

Test Command: src/tools/perf/run_benchmark -v --browser=android-chromium --output-format=chartjson --upload-results --also-run-disabled-tests thread_times.key_silk_cases
Test Metric: thread_browser_cpu_time_per_frame/thread_browser_cpu_time_per_frame
Relative Change: 6.35%
Score: 99.9

Buildbot stdio: http://build.chromium.org/p/tryserver.chromium.perf/builders/android_nexus6_perf_bisect/builds/2300
Job details: https://chromeperf.appspot.com/buildbucket_job_status/9007706735905830240


Not what you expected? We'll investigate and get back to you!
  https://chromeperf.appspot.com/bad_bisect?try_job_id=5315000994889728

| 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!

chromium@404233  1.79021  0.0207351   5  bad    <--

https://codereview.chromium.org/2101163002 This is the CL.

CL description is here;
Reland Mojo-based waiting for IPC::SyncChannel

BUG=612500
TBR=jam@chromium.org

Committed: https://crrev.com/3c23629163a036c17017c4c2d16a0ac77f62d469
Cr-Commit-Position: refs/heads/master@{#404233}

Ken, do you think this regression is reasonable, or expected?
Regression happened mainly on android.

I think some regression can be expected from the CL since it does increase the cost of sync IPC slightly. Perhaps someone more familiar with these benchamrks can clarify the significance of the regression.

These tests measure the cpu time spent producing each frame. In this particular case, it looks like the cpu time went up by about 0.12ms per frame. But looking at the graphs associated with this bug, there are also cases with larger regressions (e.g. ChromiumPerf/android-nexus5/thread_times.simple_mobile_sites / thread_total_fast_path_cpu_time_per_frame had a 0.4ms per frame regression).

Perf sheriff ping: reminder to follow up on possible performance issues

ajuma: do you think the regression is acceptable?

Yes, let's close this.