All graphs for this bug:
  https://chromeperf.appspot.com/group_report?bug_id=677459

Original alerts at time of bug-filing:
  https://chromeperf.appspot.com/group_report?keys=agxzfmNocm9tZXBlcmZyFAsSB0Fub21hbHkYgICg3-qktAoM


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

chromium-rel-mac11

Started bisect job https://chromeperf.appspot.com/buildbucket_job_status/8991947476240964608

=== PERF REGRESSION ===


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

Hi fayang@chromium.org, the bisect results pointed to your CL, please take a look at the
results.


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


===== SUSPECTED CL(s) =====
Subject : Add QuicStrCat.
Author  : fayang
Commit description:
  
Merge internal change 142661719.
Merge internal change 142781026.

BUG=

Review-Url: https://codereview.chromium.org/2591143003
Cr-Commit-Position: refs/heads/master@{#440641}
Commit  : 889bd6fc33dd8941005aa74ecceb59ceb4db2684
Date    : Fri Dec 23 17:12:21 2016


===== TESTED REVISIONS =====
Revision         Mean     Std Dev  N   Good?
chromium@440635  182.917  12.1963  30  good
chromium@440640  178.867  11.1581  30  good
chromium@440641  166.218  9.27782  30  bad    <--
chromium@440642  165.722  9.01552  30  bad
chromium@440643  164.593  12.363   30  bad
chromium@440645  164.258  8.49472  30  bad
chromium@440654  164.71   13.8765  30  bad

Bisect job ran on: mac_10_11_perf_bisect
Bug ID: 677459

Test Command: src/tools/perf/run_benchmark -v --browser=release --output-format=chartjson --upload-results --pageset-repeat=1 --also-run-disabled-tests blink_perf.layout
Test Metric: hindi-line-layout/hindi-line-layout
Relative Change: 9.95%

Buildbot stdio: http://build.chromium.org/p/tryserver.chromium.perf/builders/mac_10_11_perf_bisect/builds/1149
Job details: https://chromeperf.appspot.com/buildbucket_job_status/8991947476240964608


Not what you expected? We'll investigate and get back to you!
  https://chromeperf.appspot.com/bad_bisect?try_job_id=5833949035626496

| 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!

Does this mean our QuicStrCatImpl only hurts mac but not other platforms?
I would try to improve the performance. Sorry about this.

I'm surprised that a change to code in net/quic/ would affect this perf test. In order for a change to net/quic/ to affect this, it would need to be talking to a server via QUIC. QUIC is disabled in Chrome by default, but it's possible that this test enables it.

Where can I learn more about what blink_perf.layout does? (I'm mostly clueless about things up at the blink layer)

Could easily be a bad bisect since the graph is noisy.  I'll run it again.

Started bisect job https://chromeperf.appspot.com/buildbucket_job_status/8991858028323443408

Started bisect job https://chromeperf.appspot.com/buildbucket_job_status/8991857641551049120

===== BISECT JOB RESULTS =====
Status: failed


=== Bisection aborted ===
The bisect was aborted because Bisect cannot identify a culprit: Bisect failed to reproduce the regression with enough confidence.
Please contact the the team (see below) if you believe this is in error.

===== TESTED REVISIONS =====
Revision         Mean     Std Dev  N   Good?
chromium@440600  183.056  22.9722  30  good
chromium@440700  181.757  11.4006  30  bad

Bisect job ran on: mac_10_11_perf_bisect
Bug ID: 677459

Test Command: src/tools/perf/run_benchmark -v --browser=release --output-format=chartjson --upload-results --pageset-repeat=1 --also-run-disabled-tests blink_perf.layout
Test Metric: hindi-line-layout/hindi-line-layout
Relative Change: 0.71%

Buildbot stdio: http://build.chromium.org/p/tryserver.chromium.perf/builders/mac_10_11_perf_bisect/builds/1150
Job details: https://chromeperf.appspot.com/buildbucket_job_status/8991858028323443408


Not what you expected? We'll investigate and get back to you!
  https://chromeperf.appspot.com/bad_bisect?try_job_id=5828142172733440

| 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 : Add QuicStrCat.
Author  : fayang
Commit description:
  
Merge internal change 142661719.
Merge internal change 142781026.

BUG=

Review-Url: https://codereview.chromium.org/2591143003
Cr-Commit-Position: refs/heads/master@{#440641}
Commit  : 889bd6fc33dd8941005aa74ecceb59ceb4db2684
Date    : Fri Dec 23 17:12:21 2016


===== TESTED REVISIONS =====
Revision         Mean     Std Dev  N   Good?
chromium@440600  184.98   18.9673  30  good
chromium@440625  184.731  11.48    30  good
chromium@440638  180.115  9.5653   30  good
chromium@440640  179.897  11.0197  30  good
chromium@440641  165.018  9.13502  30  bad    <--
chromium@440644  166.9    11.5822  30  bad
chromium@440650  164.959  12.1145  30  bad
chromium@440700  182.674  10.9185  30  bad

Bisect job ran on: mac_10_11_perf_bisect
Bug ID: 677459

Test Command: src/tools/perf/run_benchmark -v --browser=release --output-format=chartjson --upload-results --pageset-repeat=1 --also-run-disabled-tests blink_perf.layout
Test Metric: hindi-line-layout/hindi-line-layout
Relative Change: 1.25%

Buildbot stdio: http://build.chromium.org/p/tryserver.chromium.perf/builders/mac_10_11_perf_bisect/builds/1151
Job details: https://chromeperf.appspot.com/buildbucket_job_status/8991857641551049120


Not what you expected? We'll investigate and get back to you!
  https://chromeperf.appspot.com/bad_bisect?try_job_id=5821623486119936

| 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!

Looks like this went unaddressed. Closing since it's 8 months old at this point. Cc-ing eae, owner of blink_perf.layout as FYI.

Thanks. I'll follow up.