All graphs for this bug:
  https://chromeperf.appspot.com/group_report?bug_id=604015

Original alerts at time of bug-filing:
  https://chromeperf.appspot.com/group_report?keys=agxzfmNocm9tZXBlcmZyFAsSB0Fub21hbHkYgICguLGopgoM


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

android-nexus6

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


===== SUSPECTED CL(s) =====
Subject : Reland of Enable allocator shim for Android (crrev.com/1875043003)
Author  : primiano
Commit description:
  
Reason for reland:
The original CL was reverted by crrev.com/1881523003 because it broke
clang builds. This CL contains the fix for clang (see diff between
patch-set 1 and 2).
The culprit of the fix is that LLVM libc++ uses _NOEXCEPT instead
of glibc's __THROW. The absence of it was causing errors like the
following:

../../base/allocator/allocator_shim_override_cpp_symbols.h:20:25: error: function previously declared with an explicit exception specification redeclared with an implicit exception specification [-Werror,-Wimplicit-exception-spec-mismatch]
SHIM_ALWAYS_EXPORT void operator delete(void* p) __THROW

Original issue's description:
> Enable allocator shim for Android
>
> This is a follow-up to crrev.com/1719433002, which introduced the
> shim for Android, and enables it by default by setting
> use_experimental_allocator_shim=true for Android.
>
> Build/Perf sheriffs heads up
> ----------------------------
> If you see any build error or crash related with __wrap_malloc,
> __wrap_free, __real_malloc, __real_free, etc this CL is to blame.
>
> Performance considerations
> ------------------------
> Binary size diff (GN, arm, static, official build): 24k
>
> I did a mixture of local and trybots run to estimate the perf impact
> of this change. Didn't get any conclusive data, everything I tried
> seems in the same ballpark, below noise levels. More in details:
>
> cc_perftests.PrepareTiles on a Nexus 4.
> Rationale of the choice: in a previous CL ( crbug.com/593344 ), this
> benchmark revealed the presence of two mfences in the malloc path.
> Results: https://goo.gl/8VC3Jp in the same ballpark.
>
> page-cycler on Nexus 9 via trybots:
> Results: http://goo.gl/J3i50a seems to suggest that this CL improves
> both warm and cold times in most cases. I doubt it, more likely it's
> noise.
>
> All the other perf trybots failed. The perf waterfall seems to be in a
> bad state in these days.
>
> BUG=550886,598075
> TEST=base_unittests --gtest_filter=AllocatorShimTest.*
> TBR=thakis@chromium.org
>
> Committed: https://crrev.com/ebb95496c73dc0d5ce83968ac619921f154305f7
> Cr-Commit-Position: refs/heads/master@{#386386}

BUG=550886,598075
CC=dalecurtis@chromium.org

Review URL: https://codereview.chromium.org/1875173002

Cr-Commit-Position: refs/heads/master@{#386444}
Commit  : 88bf797383cd290d9bd23db0045c5fb23e010beb
Date    : Mon Apr 11 19:51:08 2016


===== TESTED REVISIONS =====
Revision                Mean Value  Std. Dev.   Num Values  Good?
chromium@386410         0.55189     0.001139    5           good
chromium@386437         0.55149     0.00093     5           good
chromium@386441         0.551724    0.001353    5           good
chromium@386443         0.551117    0.001324    5           good
chromium@386444         0.567241    0.001618    5           bad         <-
chromium@386451         0.568414    0.001267    5           bad
chromium@386464         0.567007    0.001848    5           bad

Bisect job ran on: android_nexus6_perf_bisect
Bug ID: 604015

Test Command: src/tools/perf/run_benchmark -v --browser=android-chromium --output-format=chartjson --also-run-disabled-tests rasterize_and_record_micro.key_silk_cases
Test Metric: record_time/record_time
Relative Change: 2.74%
Score: 99.9

Buildbot stdio: http://build.chromium.org/p/tryserver.chromium.perf/builders/android_nexus6_perf_bisect/builds/2136
Job details: https://chromeperf.appspot.com/buildbucket_job_status/9015283963298332000


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  https://chromeperf.appspot.com/bad_bisect?try_job_id=604015

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