All graphs for this bug:
  https://chromeperf.appspot.com/group_report?bug_id=758336

(For debugging:) Original alerts at time of bug-filing:
  https://chromeperf.appspot.com/group_report?sid=bc25b633867a7cf8f616b4cd350c92f3ec5443dbf078e0157f03ff1d564bed1b


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

chromium-rel-mac-retina

Started bisect job https://chromeperf.appspot.com/buildbucket_job_status/8970443429906601392

=== BISECT JOB RESULTS ===
NO Perf regression found

Bisect Details
  Configuration: mac_retina_perf_bisect
  Benchmark    : system_health.common_desktop
  Metric       : timeToFirstContentfulPaint_avg/load_social/load_social_pinterest

Revision             Result                  N
chromium@495262      530.006 +- 254.374      21      good
chromium@495450      540.602 +- 294.897      21      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=load.social.pinterest system_health.common_desktop

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

Debug information about this bisect:
  https://chromeperf.appspot.com/buildbucket_job_status/8970443429906601392


For feedback, file a bug with component Speed>Bisection

Started bisect job https://chromeperf.appspot.com/buildbucket_job_status/8970374985265885584

=== BISECT JOB RESULTS ===
Bisect failed for unknown reasons

Please contact the team (see below) and report the error.


Bisect Details
  Configuration: mac_retina_perf_bisect
  Benchmark    : system_health.common_desktop
  Metric       : timeToFirstContentfulPaint_avg/load_social/load_social_pinterest


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.social.pinterest system_health.common_desktop

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

Debug information about this bisect:
  https://chromeperf.appspot.com/buildbucket_job_status/8970374985265885584


For feedback, file a bug with component Speed>Bisection

Started bisect job https://chromeperf.appspot.com/buildbucket_job_status/8970260044089398512

+shaseley: Looks like the bisect identified your CL as a culprit, but failed to upload the data back so it could be posted to the bug correctly: https://chromium-review.googlesource.com/576371

I'm going to kick off another bisect to check.

=== BISECT JOB RESULTS ===
Bisect failed for unknown reasons

Please contact the team (see below) and report the error.


Bisect Details
  Configuration: mac_retina_perf_bisect
  Benchmark    : system_health.common_desktop
  Metric       : timeToFirstContentfulPaint_avg/load_social/load_social_pinterest


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.social.pinterest system_health.common_desktop

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

Debug information about this bisect:
  https://chromeperf.appspot.com/buildbucket_job_status/8970260044089398512


For feedback, file a bug with component Speed>Bisection

+panicker@

sullivan@: For timeToFirstPaint and timeToFirstContentful paint (graphs 2,3,4), I'd expect my CL to be the culprit. We moved the point where we record these timestamps on 8/10, so performance appears to be degraded, but is actually just more accurate. See comment 4 for  issue 754847 : https://bugs.chromium.org/p/chromium/issues/detail?id=754847 for full explanation and justification. Several bugs have been merged into that issue.

However, I would not expect my CL to have any impact on energy (first graph), unless FP/FCP/FMP is being used as part of a stopping point or somehow involved in the computation. But, I'm guessing that's not likely and I would suspect something else is causing the energy regression.

sullivan@ could you assign an owner for the energy regression? that is unrelated to Scott's change

Sorry for the delay, was on vacation. Split the energy regression into a separate bug. panicker, shaseley, looks like either WontFix-ing or duping into 754847 is the right action on this bug? Please go ahead and do what sounds best.

 Issue 758335  has been merged into this issue.

WontFixing per #11