All graphs for this bug:
  https://chromeperf.appspot.com/group_report?bug_id=752065

(For debugging:) Original alerts at time of bug-filing:
  https://chromeperf.appspot.com/group_report?sid=682fe6e0ada7fb4be9ccdc3803e2017bf95ea6de2cf82f0abe0aa244b5ac37a4


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

chromium-rel-mac11
chromium-rel-mac12
chromium-rel-win7-dual
chromium-rel-win8-dual

Started bisect job https://chromeperf.appspot.com/buildbucket_job_status/8972283008444269168

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

Hi xunjieli@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 : Helen Li
  Commit : 05ee1dbfaf0aa7c03b9ea2040f0345277042d0f1
  Date   : Mon Jul 31 13:24:01 2017
  Subject: [wpr-go] Switch system_health_desktop.json to use go

Bisect Details
  Configuration: mac_10_12_perf_bisect
  Benchmark    : v8.runtimestats.browsing_desktop
  Metric       : IC:duration_avg/browse_tech/browse_tech_discourse_infinite_scroll
  Change       : 12.34% | 350.016833333 -> 393.208666667

Revision             Result                  N
chromium@490749      350.017 +- 21.4056      6      good
chromium@490750      358.821 +- 23.5254      6      good
chromium@490751      399.66 +- 26.8199       6      bad       <--
chromium@490752      400.933 +- 18.7673      6      bad
chromium@490754      395.555 +- 14.0936      6      bad
chromium@490758      405.755 +- 28.378       6      bad
chromium@490767      394.42 +- 19.4015       6      bad
chromium@490784      393.209 +- 23.0078      6      bad

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=browse.tech.discourse.infinite.scroll v8.runtimestats.browsing_desktop

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

Debug information about this bisect:
  https://chromeperf.appspot.com/buildbucket_job_status/8972283008444269168


For feedback, file a bug with component Speed>Bisection

I will mark this one as WontFix because slight changes in performance characteristics after migration are expected. I didn't see anything obviously wrong going on here.

There's a 12% regression on JS duration on infinite scroll. This is not a slight regression. I would like to have at least a clarification that somewhat explains this spike.

Is it maybe faster processing of requests, so that the benchmarks can spend more time in JS? Is there something we could look at that would support this theory?

> Is it maybe faster processing of requests, so that the benchmarks can spend more time in JS? Is there something we could look at that would support this theory?

I have exhausted my options given that I know almost nothing about v8 -- not sure what these measure. I don't think I am the best person to investigate here. The pages load the same to me. 

This issue has been Available for over a year. If it's no longer important or seems unlikely to be fixed, please consider closing it out. If it is important, please re-triage the issue.

Sorry for the inconvenience if the bug really should have been left as Available.

For more details visit https://www.chromium.org/issue-tracking/autotriage - Your friendly Sheriffbot