All graphs for this bug:
  https://chromeperf.appspot.com/group_report?bug_id=752159

(For debugging:) Original alerts at time of bug-filing:
  https://chromeperf.appspot.com/group_report?sid=bbf4b15610d45b9dd3e72d5b21d3e070196be7341fffdae658337b93e76d753b


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

chromium-rel-mac-retina
chromium-rel-mac11
chromium-rel-mac12
chromium-rel-win7-gpu-intel

Started bisect job https://chromeperf.appspot.com/buildbucket_job_status/8972265664774821936

=== 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_retina_perf_bisect
  Benchmark    : v8.browsing_desktop
  Metric       : v8-gc-latency-mark-compactor_avg/browse_media/browse_media_imgur
  Change       : 35.84% | 4.7696989899 -> 6.47903935185

Revision             Result                   N
chromium@490743      4.7697 +- 0.867773       6      good
chromium@490748      4.97524 +- 0.789483      9      good
chromium@490750      4.98076 +- 0.662259      6      good
chromium@490751      7.39846 +- 1.82879       6      bad       <--
chromium@490752      6.91362 +- 3.49115       9      bad
chromium@490761      6.7902 +- 3.53579        9      bad
chromium@490778      6.47904 +- 2.04791       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.media.imgur v8.browsing_desktop

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

Debug information about this bisect:
  https://chromeperf.appspot.com/buildbucket_job_status/8972265664774821936


For feedback, file a bug with component Speed>Bisection

ulan@: The slight increase is probably benign. I don't see anything obvious wrong here. The metrics are consistent as well. 
My only explanation is that because the backend is different, that slight changes in performance characteristics are expected. Can we mark this WontFix?

In another thread you mentioned that there was a bug in conversion script. Did the graphs recover after the fix?

I haven't done that yet. I landed a fix last week to fix some false memory improvements ( Issue 752466 ). Since the metrics are stable now, I can try do the conversion again.

The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/f279e9f5a1c799992914f5fcee44b7ce970bab3c

commit f279e9f5a1c799992914f5fcee44b7ce970bab3c
Author: Helen Li <xunjieli@chromium.org>
Date: Mon Aug 07 19:55:20 2017

[wpr-go] Re-convert imgur archive (system_health_desktop_025.wprgo)

This CL redos the conversion of imgur archive (system_health_desktop_025.wprgo)
to see if injecting deterministic.js twice is the culprit for regressions in
V8 metrics.

Bug:  752159 , 750299
Change-Id: I994cbb672a5c02d4aff773bd3237a451c67a9551
Reviewed-on: https://chromium-review.googlesource.com/604127
Reviewed-by: Ned Nguyen <nednguyen@google.com>
Reviewed-by: Ulan Degenbaev <ulan@chromium.org>
Commit-Queue: Helen Li <xunjieli@chromium.org>
Cr-Commit-Position: refs/heads/master@{#492388}
[modify] https://crrev.com/f279e9f5a1c799992914f5fcee44b7ce970bab3c/tools/perf/page_sets/data/system_health_desktop_025.wprgo.sha1

The CL (r492388) doesn't have an effect on v8-gc-latency-mark-compactor_avg/browse_media/browse_media_imgur. (https://chromeperf.appspot.com/group_report?sid=bbf4b15610d45b9dd3e72d5b21d3e070196be7341fffdae658337b93e76d753b).

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.