All graphs for this bug:
  https://chromeperf.appspot.com/group_report?bug_id=595711

Original alerts at time of bug-filing:
  https://chromeperf.appspot.com/group_report?keys=agxzfmNocm9tZXBlcmZyFAsSB0Fub21hbHkYgICgoKLdqQoM


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

chromium-rel-mac-retina

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

Hi keishi@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 : Refactor RegionTree
Author  : keishi
Commit description:
  
This creates a new class, RegionTree, so we can reference the binary search tree and the mutex as one thing.

BUG= 591606 

Review URL: https://codereview.chromium.org/1804863002

Cr-Commit-Position: refs/heads/master@{#381451}
Commit  : 5227ab950a8d9de588844a3109a16094041c13a8
Date    : Wed Mar 16 14:48:23 2016


===== TESTED REVISIONS =====
Revision                Mean Value  Std. Dev.   Num Values  Good?
chromium@381450         260.621375  6.588772    8           good
chromium@381451         284.9498    2.533561    5           bad
chromium@381452         288.069     5.605063    5           bad
chromium@381453         283.1708    3.021063    5           bad
chromium@381456         282.9948    1.972866    5           bad
chromium@381460         286.3414    5.250937    5           bad
chromium@381470         283.77725   2.573939    8           bad

Bisect job ran on: mac_retina_perf_bisect
Bug ID: 595711

Test Command: src/tools/perf/run_benchmark -v --browser=release --output-format=chartjson --also-run-disabled-tests blink_perf.layout
Test Metric: floats_20_100/floats_20_100
Relative Change: 8.25%
Score: 99.9

Buildbot stdio: http://build.chromium.org/p/tryserver.chromium.perf/builders/mac_retina_perf_bisect/builds/1214
Job details: https://chromeperf.appspot.com/buildbucket_job_status/9017934603296421840


| 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 label Cr-Tests-AutoBisect.  Thank you!

Ping keishi@, can you check if your CL caused the regression?

gentle ping keishi@, could you please check the issue and update.

keishi, this regression continues. Please take a look.

Ping keishi!

CC: haraken@, the reviewer of the CL

https://codereview.chromium.org/1804863002 is simple refactoring that shouldn't affect layout performance. Also the regression is observed only in one specific bot. I think it would be fair to treat this as a noise.