All graphs for this bug:
  https://chromeperf.appspot.com/group_report?bug_id=645877

Original alerts at time of bug-filing:
  https://chromeperf.appspot.com/group_report?keys=agxzfmNocm9tZXBlcmZyFAsSB0Fub21hbHkYgICgycmK7QoM,agxzfmNocm9tZXBlcmZyFAsSB0Fub21hbHkYgICgqZ_DrgoM


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

android-galaxy-s5
android-nexus7v2

Started bisect job https://chromeperf.appspot.com/buildbucket_job_status/9001740782602674432

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


=== Bisection aborted ===
The bisect was aborted because The metric values for the initial "good" and "bad" revisions do not represent a clear regression.
Please contact the the team (see below) if you believe this is in error.

=== Warnings ===
The following warnings were raised by the bisect job:

 * Bisect failed to reproduce the regression with enough confidence.

===== TESTED REVISIONS =====
Revision         Mean     Std Dev  N   Good?
chromium@417850  971.18   40.1237  18  good
chromium@417852  969.449  39.0936  18  bad

Bisect job ran on: android_s5_perf_bisect
Bug ID: 645877

Test Command: src/tools/perf/run_benchmark -v --browser=android-chromium --output-format=chartjson --upload-results --also-run-disabled-tests speedometer
Test Metric: VanillaJS-TodoMVC/VanillaJS-TodoMVC
Relative Change: 1.12%
Score: 0

Buildbot stdio: http://build.chromium.org/p/tryserver.chromium.perf/builders/android_s5_perf_bisect/builds/992
Job details: https://chromeperf.appspot.com/buildbucket_job_status/9001740782602674432


Not what you expected? We'll investigate and get back to you!
  https://chromeperf.appspot.com/bad_bisect?try_job_id=5841751669997568

| 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!

Started bisect job https://chromeperf.appspot.com/buildbucket_job_status/9001734461836596576

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


===== SUSPECTED CL(s) =====
Subject : Revert of Make canceling Timers fast. (patchset #10 id:180001 of https://codereview.chromium.org/2319053004/ )
Author  : fs
Commit description:
  
Reason for revert:
Wreaks havoc on the ASAN bots:

https://build.chromium.org/p/chromium.webkit/builders/WebKit%20Linux%20ASAN

STDERR: =================================================================
STDERR: ==4==ERROR: AddressSanitizer: use-after-poison on address 0x7ed9a5616190 at pc 0x00000768b0da bp 0x7fff4bbca630 sp 0x7fff4bbca628
STDERR: READ of size 8 at 0x7ed9a5616190 thread T0 (content_shell)
STDERR:     #0 0x768b0d9 in operator-> third_party/WebKit/Source/wtf/RefPtr.h:68:50
STDERR:     #1 0x768b0d9 in revokeAll third_party/WebKit/Source/wtf/WeakPtr.h:146:0
STDERR:     #2 0x768b344 in ?? third_party/WebKit/Source/platform/Timer.cpp:124:22
STDERR:     #3 0x47a4461 in Run base/callback.h:56:12
STDERR:     #4 0x47a4461 in RunTask base/debug/task_annotator.cc:54:0
STDERR:     #5 0x79e2381 in ProcessTaskFromWorkQueue third_party/WebKit/Source/platform/scheduler/base/task_queue_manager.cc:316:19
...
STDERR: AddressSanitizer can not describe address in more detail (wild memory access suspected).
STDERR: SUMMARY: AddressSanitizer: use-after-poison

Appears to be accessing a "user-poison" area, so maybe a timer in something that was swept? (Wild guess.)

Original issue's description:
> Make canceling Timers fast.
>
> base::Closure recently got an IsCancelled method. Taking advantage of
> that the scheduler can short circuit a bunch of logic for cancelled
> tasks and avoid running them and the rest of the task selection
> machinery.
>
> On the new TimerPerfTest benchmark this makes running 10000 cancelled
> tasks aprox 50x - 60x faster (measured on Android and Linux).
>
> Note this patch reverts many of the changes made in
> https://codereview.chromium.org/2258713004 in favor of
> WeakPtr based cancellation as favored by the base owners.
>
> BUG= 605718 ,  638542 
>
> Committed: https://crrev.com/e4e5868c5f32b015bf0d07a6eeace892d6a789a1
> Cr-Commit-Position: refs/heads/master@{#417621}

TBR=jochen@chromium.org,haraken@chromium.org,skyostil@chromium.org,alexclarke@chromium.org
# Not skipping CQ checks because original CL landed more than 1 days ago.
BUG= 605718 ,  638542 

Review-Url: https://codereview.chromium.org/2326313003
Cr-Commit-Position: refs/heads/master@{#417846}
Commit  : bee7b64b4772d14c9cafc00f60629a89e8f5bf81
Date    : Sat Sep 10 21:59:53 2016


===== TESTED REVISIONS =====
Revision         Mean     Std Dev  N   Good?
chromium@417837  914.805  17.6412  12  good
chromium@417842  899.321  18.003   5   good
chromium@417844  908.501  10.6406  5   good
chromium@417845  893.602  4.09357  5   good
chromium@417846  982.066  40.1345  5   bad    <--
chromium@417855  961.43   38.301   12  bad

Bisect job ran on: android_s5_perf_bisect
Bug ID: 645877

Test Command: src/tools/perf/run_benchmark -v --browser=android-chromium --output-format=chartjson --upload-results --also-run-disabled-tests speedometer
Test Metric: VanillaJS-TodoMVC/VanillaJS-TodoMVC
Relative Change: 4.49%
Score: 98.0

Buildbot stdio: http://build.chromium.org/p/tryserver.chromium.perf/builders/android_s5_perf_bisect/builds/993
Job details: https://chromeperf.appspot.com/buildbucket_job_status/9001734461836596576


Not what you expected? We'll investigate and get back to you!
  https://chromeperf.appspot.com/bad_bisect?try_job_id=5852100662132736

| 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!