All graphs for this bug:
  https://chromeperf.appspot.com/group_report?bug_id=762494

(For debugging:) Original alerts at time of bug-filing:
  https://chromeperf.appspot.com/group_report?sid=f50340e7febf55b1ccfc0c03abfb0eea34178777e5f8a2f919386a0c7f617579


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

android-nexus7v2
chromium-rel-win7-dual
chromium-rel-win7-x64-dual
chromium-rel-win8-dual

Started bisect job https://chromeperf.appspot.com/buildbucket_job_status/8969198605892167968

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

Suspected Commit
  Author : Marja Hölttä
  Commit : 36d703778ccd0d2777e0d4b69ed6e65e39a9f521
  Date   : Mon Sep 04 16:05:39 2017
  Subject: [parser] Tentatively enable FLAG_preparser_scope_analysis.

Bisect Details
  Configuration: win_perf_bisect
  Benchmark    : system_health.memory_desktop
  Metric       : memory:chrome:renderer_processes:reported_by_chrome:v8:heap:effective_size_avg/load_games/load_games_lazors
  Change       : 11.97% | 4378624.0 -> 4902912.0

Revision                           Result              N
chromium@499527                    4378624 +- 0.0      6      good
chromium@499534                    4378624 +- 0.0      6      good
chromium@499538                    4378624 +- 0.0      6      good
chromium@499538,v8@1c1457fa70      4378624 +- 0.0      6      good
chromium@499538,v8@36d703778c      4902912 +- 0.0      6      bad       <--
chromium@499538,v8@7abdadca0e      4902912 +- 0.0      6      bad
chromium@499539                    4902912 +- 0.0      6      bad
chromium@499540                    4902912 +- 0.0      6      bad
chromium@499541                    4902912 +- 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=release --output-format=chartjson --upload-results --pageset-repeat=1 --also-run-disabled-tests --story-filter=load.games.lazors system_health.memory_desktop

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

Debug information about this bisect:
  https://chromeperf.appspot.com/buildbucket_job_status/8969198605892167968


For feedback, file a bug with component Speed>Bisection

This looks odd.

The commit in question was rolled in Chromium in r 499539, and a commit turning the flag back off ( https://chromium-review.googlesource.com/c/v8/v8/+/690077 ) was rolled to Chromium in r 505211.

However, the graph https://chromeperf.appspot.com/report?sid=eec13b3d75f894eb867ac4b90e4a339ae30f592c4dbe940c376c55b781ec0cca&start_rev=488147&end_rev=505238 doesn't go down at all with the revert.

So something's not right here...

Yeah, I don't know either. Given that this is only on one platform and the revert doesn't resolve it, I'd be tempted to ignore this specific regression if you are already tracking 'more solidly reproducible regressions' on other bugs.