All graphs for this bug:
  https://chromeperf.appspot.com/group_report?bug_id=801729

(For debugging:) Original alerts at time of bug-filing:
  https://chromeperf.appspot.com/group_report?sid=554a2378af717503a8f2bded3f5d3e38f36a379a56f85d5e672cf65879ba21ed


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

android-nexus5X

Started bisect job https://chromeperf.appspot.com/buildbucket_job_status/8957561252748824304

=== Auto-CCing suspected CL author bratell@opera.com ===

Hi bratell@opera.com, the bisect results pointed to your CL, please take a look at the
results.


=== BISECT JOB RESULTS ===
Perf regression found with culprit

Suspected Commit
  Author : Daniel Bratell
  Commit : 230062bad12dcf14ff1c1592c67e9e620a62f19b
  Date   : Tue Jan 09 20:09:03 2018
  Subject: Deduplicate printing HoldRefCallback helper

Bisect Details
  Configuration: android_nexus5X_perf_bisect
  Benchmark    : smoothness.tough_animation_cases
  Metric       : frame_times/css_value_type_length_3d.html?api_web_animations_N_0316
  Change       : 0.78% | 29.3998335221 -> 29.1690862609

Revision             Result                   N
chromium@527989      29.3998 +- 1.23993       21      good
chromium@528036      29.5493 +- 0.377454      6       good
chromium@528060      29.3648 +- 0.729061      14      good
chromium@528073      29.3872 +- 0.767654      14      good
chromium@528076      29.6132 +- 3.08791       14      good
chromium@528082      30.2801 +- 10.7965       21      good
chromium@528083      29.1691 +- 0.979262      21      bad       <--

To Run This Test
  src/tools/perf/run_benchmark -v --browser=android-chromium --output-format=chartjson --upload-results --pageset-repeat=1 --also-run-disabled-tests --story-filter=css.value.type.length.3d.html.api.web.animations.N.0316 smoothness.tough_animation_cases

More information on addressing performance regressions:
  http://g.co/ChromePerformanceRegressions

Debug information about this bisect:
  https://chromeperf.appspot.com/buildbucket_job_status/8957561252748824304


For feedback, file a bug with component Speed>Bisection

That bisect job was drunk. It seems like the "bad" in the bisect was ~1% worse than "good" and not the 50% regression it should have been looking for.

Also the commit deduplicates some print helper function and is unlikely to affect css animation performance.

benhenry, can you start a new bisect?

Looking at the graph, it looks like the test became unstable Nov 29 and since then it's not been reliable. Not sure if this is the testing system or the software.

Started bisect job https://chromeperf.appspot.com/buildbucket_job_status/8957324404082680560

I agree the metric here [1] is noisy and not that useful. There does not seem to be a real regression here. Assigning to metric owner is case they can/want to improve 
the metric here or just close the issue.

[1] "smoothness.tough_animation_cases/frame_times/css_value_type_length_3d.html?api_web_animations_N_0316"

Looks like the bisect in #6 found crrev.com/c/612629 as the culprit for earlier regression; I'm not sure why it did not update the bug. Anyways, the metric is recovered.