All graphs for this bug:
  https://chromeperf.appspot.com/group_report?bug_id=758230

(For debugging:) Original alerts at time of bug-filing:
  https://chromeperf.appspot.com/group_report?sid=73d91d98d971214a941ff36d727802979a5d98158982b453d8837a89352dfc3a


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

android-one

Started bisect job https://chromeperf.appspot.com/buildbucket_job_status/8970455728336223376

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

Hi xidachen@chromium.org, 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 : Xida Chen
  Commit : 177134823106e782420b7ce5150c2aa137014ee2
  Date   : Wed Aug 16 02:35:04 2017
  Subject: Use half-width GPU tiles on low-end android devices

Bisect Details
  Configuration: android_one_perf_bisect
  Benchmark    : thread_times.key_silk_cases
  Metric       : thread_renderer_compositor_cpu_time_per_frame/http___jsfiddle.net_xLuvC_1_show_
  Change       : 14.09% | 3.56463790961 -> 4.06703160871

Revision             Result                    N
chromium@494609      3.56464 +- 0.0560376      6      good
chromium@494657      3.55386 +- 0.0440732      6      good
chromium@494669      3.51718 +- 0.0611333      6      good
chromium@494672      3.51131 +- 0.0498725      6      good
chromium@494673      4.06521 +- 0.082022       6      bad       <--
chromium@494674      4.09471 +- 0.0493758      6      bad
chromium@494675      4.1055 +- 0.0854747       6      bad
chromium@494681      4.08855 +- 0.0359438      6      bad
chromium@494704      4.06703 +- 0.0703297      6      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=http...jsfiddle.net.xLuvC.1.show. thread_times.key_silk_cases

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

Debug information about this bisect:
  https://chromeperf.appspot.com/buildbucket_job_status/8970455728336223376


For feedback, file a bug with component Speed>Bisection

ericrk@: this is likely legitimate since we reduce the tile size of be half. It impact low-end android device only.

Yeah, we're probably going to have to make a call on whether any benefits outweigh these downsides, once we have better UMA data.

ericrk@: do we have an effective UMA to measure this? Note this is caused by our decision to cut tile size by half, if the tile_width > screen_width.

 Issue 759035  has been merged into this issue.

 Issue 759612  has been merged into this issue.

 Issue 759695  has been merged into this issue.

 Issue 759611  has been merged into this issue.