All graphs for this bug:
  https://chromeperf.appspot.com/group_report?bug_id=631036

Original alerts at time of bug-filing:
  https://chromeperf.appspot.com/group_report?keys=agxzfmNocm9tZXBlcmZyFAsSB0Fub21hbHkYgICguuS-pwoM


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

chromium-rel-mac-retina

Started bisect job https://chromeperf.appspot.com/buildbucket_job_status/9006155787133122368

Started bisect job https://chromeperf.appspot.com/buildbucket_job_status/9006155775111121312

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


===== SUSPECTED CL(s) =====
Subject : Fix infinite recursion crash in HarfBuzz' CoreText backend
Author  : drott
Commit description:
  
The font cascade reconfiguration which was introduced as fix for AAT
shaping performance regressions in  crbug.com/547912  seems to
occasionally cause CoreText crashes on OS X 10.9. We don't have a better
way of detecting this than by OS or CoreText API version number. This is
one of our top Mac crashers on Mac OS 10.9 with Chrome across versions [1].

This crash does not occur in newer versions of OS X and we can keep this
important performance optimization enabled there.

A big thanks to Robert Sesek (rsesek@) for the patient and thorough
initial investigation. Discussing and working together on this issue we
were able to identify the crash triggering code in HarfBuzz in this
case.

[1] https://bugs.chromium.org/p/chromium/issues/detail?id=576941#c74

BUG= 576941 ,  625902 

Review-Url: https://codereview.chromium.org/2173883002
Cr-Commit-Position: refs/heads/master@{#407185}
Commit  : 64a2d4d02ea769c849df4718d196df12a3f79091
Date    : Fri Jul 22 17:18:48 2016


===== TESTED REVISIONS =====
Revision         Mean     Std Dev   N  Good?
chromium@407162  150.913  0.682918  5  good
chromium@407174  151.414  0.662719  5  good
chromium@407180  151.64   0.613618  5  good
chromium@407183  151.676  0.484558  5  good
chromium@407184  151.366  1.04209   5  good
chromium@407185  60.2195  0.13434   5  bad    <--

Bisect job ran on: mac_retina_perf_bisect
Bug ID: 631036

Test Command: src/tools/perf/run_benchmark -v --browser=release --output-format=chartjson --upload-results --also-run-disabled-tests blink_perf.layout
Test Metric: ArabicLineLayout/ArabicLineLayout
Relative Change: 60.10%
Score: 99.9

Buildbot stdio: http://build.chromium.org/p/tryserver.chromium.perf/builders/mac_retina_perf_bisect/builds/1440
Job details: https://chromeperf.appspot.com/buildbucket_job_status/9006155787133122368


Not what you expected? We'll investigate and get back to you!
  https://chromeperf.appspot.com/bad_bisect?try_job_id=5704195915644928

| 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!

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


===== SUSPECTED CL(s) =====
Subject : Fix infinite recursion crash in HarfBuzz' CoreText backend
Author  : drott
Commit description:
  
The font cascade reconfiguration which was introduced as fix for AAT
shaping performance regressions in  crbug.com/547912  seems to
occasionally cause CoreText crashes on OS X 10.9. We don't have a better
way of detecting this than by OS or CoreText API version number. This is
one of our top Mac crashers on Mac OS 10.9 with Chrome across versions [1].

This crash does not occur in newer versions of OS X and we can keep this
important performance optimization enabled there.

A big thanks to Robert Sesek (rsesek@) for the patient and thorough
initial investigation. Discussing and working together on this issue we
were able to identify the crash triggering code in HarfBuzz in this
case.

[1] https://bugs.chromium.org/p/chromium/issues/detail?id=576941#c74

BUG= 576941 ,  625902 

Review-Url: https://codereview.chromium.org/2173883002
Cr-Commit-Position: refs/heads/master@{#407185}
Commit  : 64a2d4d02ea769c849df4718d196df12a3f79091
Date    : Fri Jul 22 17:18:48 2016


===== TESTED REVISIONS =====
Revision         Mean     Std Dev    N  Good?
chromium@407162  150.647  0.495674   5  good
chromium@407174  151.567  0.306716   5  good
chromium@407180  151.057  0.705174   5  good
chromium@407183  151.488  0.389432   5  good
chromium@407184  151.469  0.859321   5  good
chromium@407185  60.6545  0.0888652  5  bad    <--

Bisect job ran on: mac_retina_perf_bisect
Bug ID: 631036

Test Command: src/tools/perf/run_benchmark -v --browser=release --output-format=chartjson --upload-results --also-run-disabled-tests blink_perf.layout
Test Metric: ArabicLineLayout/ArabicLineLayout
Relative Change: 59.74%
Score: 99.9

Buildbot stdio: http://build.chromium.org/p/tryserver.chromium.perf/builders/mac_retina_perf_bisect/builds/1441
Job details: https://chromeperf.appspot.com/buildbucket_job_status/9006155775111121312


Not what you expected? We'll investigate and get back to you!
  https://chromeperf.appspot.com/bad_bisect?try_job_id=5108488984854528

| 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!