All graphs for this bug:
  https://chromeperf.appspot.com/group_report?bug_id=774082

(For debugging:) Original alerts at time of bug-filing:
  https://chromeperf.appspot.com/group_report?sid=1f6b8ce8bb81f91c2e8b63a2f6ddac4a7167a9692b774046b0274d19abdb2fd9


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

android-webview-nexus5X

Started bisect job https://chromeperf.appspot.com/buildbucket_job_status/8965933120182427440

=== Auto-CCing suspected CL author bsalomon@google.com ===

Hi bsalomon@google.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 : Brian Salomon
  Commit : 7f56d3d2d865a9fed44c420bd3b9497118b7ed26
  Date   : Mon Oct 09 20:24:04 2017
  Subject: Revert "Revert "Disable GL buffer mapping on TSAN/Mac.""

Bisect Details
  Configuration: android_webview_arm64_aosp_perf_bisect
  Benchmark    : system_health.memory_mobile
  Metric       : memory:webview:all_processes:reported_by_chrome:gpu:effective_size_avg/load_media/load_media_soundcloud
  Change       : 92.38% | 2270112.0 -> 4367264.0

Revision                             Result              N
chromium@507657                      2270112 +- 0.0      6      good
chromium@507661                      2270112 +- 0.0      6      good
chromium@507662                      2270112 +- 0.0      6      good
chromium@507662,skia@df007e1a7a      2270112 +- 0.0      6      good
chromium@507662,skia@c795a4c886      2270112 +- 0.0      6      good
chromium@507662,skia@7f56d3d2d8      4367264 +- 0.0      6      bad       <--
chromium@507662,skia@29380bdd56      4367264 +- 0.0      6      bad
chromium@507662,skia@3f98552933      4367264 +- 0.0      6      bad
chromium@507663                      4367264 +- 0.0      6      bad
chromium@507664                      4367264 +- 0.0      6      bad
chromium@507670                      4367264 +- 0.0      6      bad
chromium@507682                      4367264 +- 0.0      6      bad
chromium@507707                      4367264 +- 0.0      6      bad

Please refer to the following doc on diagnosing memory regressions:
  https://chromium.googlesource.com/chromium/src/+/master/docs/memory-infra/memory_benchmarks.md

To Run This Test
  src/tools/perf/run_benchmark -v --browser=android-webview --output-format=chartjson --upload-results --pageset-repeat=1 --also-run-disabled-tests --story-filter=load.media.soundcloud system_health.memory_mobile

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

Debug information about this bisect:
  https://chromeperf.appspot.com/buildbucket_job_status/8965933120182427440


For feedback, file a bug with component Speed>Bisection

My change was a revert to previous behavior in order to fix this performance regression:  Issue 768554 .

If it would be preferable to trade the perf for reduced memory please reopen and I can revert.

Issue 774070 has been merged into this issue.

 Issue 775316  has been merged into this issue.