All graphs for this bug:
  https://chromeperf.appspot.com/group_report?bug_id=661546

Original alerts at time of bug-filing:
  https://chromeperf.appspot.com/group_report?keys=agxzfmNocm9tZXBlcmZyFAsSB0Fub21hbHkYgICgo7T4qQoM


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

android-nexus5

Started bisect job https://chromeperf.appspot.com/buildbucket_job_status/8997106470546430576

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


===== TESTED REVISIONS =====
Revision         Mean     Std Dev   N  Good?
chromium@428332  110.618  4.78789   5  good
chromium@428342  112.732  1.33707   5  good
chromium@428347  109.081  6.72971   5  good
chromium@428349  91.5811  0.192708  5  bad
chromium@428351  89.2633  2.57607   6  bad

Bisect job ran on: android_nexus5_perf_bisect
Bug ID: 661546

Test Command: src/tools/perf/run_benchmark -v --browser=android-chromium --output-format=chartjson --upload-results --pageset-repeat=1 --also-run-disabled-tests blink_perf.bindings
Test Metric: undefined-first-child/undefined-first-child
Relative Change: 18.70%
Score: 0

Buildbot stdio: http://build.chromium.org/p/tryserver.chromium.perf/builders/android_nexus5_perf_bisect/builds/4317
Job details: https://chromeperf.appspot.com/buildbucket_job_status/8997106470546430576


Not what you expected? We'll investigate and get back to you!
  https://chromeperf.appspot.com/bad_bisect?try_job_id=5819770417446912

| 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 the bisect got interrupted somehow? Rerunning.

Started bisect job https://chromeperf.appspot.com/buildbucket_job_status/8996896008917307216

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

Hi leszeks@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 : [ignition] Add bytecodes for loads/stores in the current context
Author  : leszeks
Commit description:
  
The majority of context slot accesses are to the local context (current context
register and depth 0), so this adds bytecodes to optimise for that case.

This cuts down bytecode size by roughly 1% (measured on Octane and Top25).

Review-Url: https://codereview.chromium.org/2459513002
Cr-Commit-Position: refs/heads/master@{#40641}
Commit  : d2caa302a7bc8cd54dbfaf4e4cfbb3fb81ada378
Date    : Fri Oct 28 10:11:06 2016


===== TESTED REVISIONS =====
Revision                       Mean     Std Dev   N  Good?
chromium@428347                109.656  8.60537   5  good
chromium@428348                112.396  2.07309   5  good
chromium@428348,v8@3c2e379750  108.725  5.74114   5  good
chromium@428348,v8@d2caa302a7  89.9379  1.87462   5  bad    <--
chromium@428348,v8@c646c1ccd7  91.4076  0.279115  5  bad
chromium@428349                90.0819  1.96931   5  bad

Bisect job ran on: android_nexus5_perf_bisect
Bug ID: 661546

Test Command: src/tools/perf/run_benchmark -v --browser=android-chromium --output-format=chartjson --upload-results --pageset-repeat=1 --also-run-disabled-tests blink_perf.bindings
Test Metric: undefined-first-child/undefined-first-child
Relative Change: 17.85%
Score: 99.5

Buildbot stdio: http://build.chromium.org/p/tryserver.chromium.perf/builders/android_nexus5_perf_bisect/builds/4320
Job details: https://chromeperf.appspot.com/buildbucket_job_status/8996896008917307216


Not what you expected? We'll investigate and get back to you!
  https://chromeperf.appspot.com/bad_bisect?try_job_id=5002451160137728

| 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!

I don't think this would have been Leszek's change. Also graph looks like it's recovered, so marking as wontfix.

Sounds good to me :)