All graphs for this bug:
  https://chromeperf.appspot.com/group_report?bug_id=844452

(For debugging:) Original alerts at time of bug-filing:
  https://chromeperf.appspot.com/group_report?sid=8dffc9ed6296bb9e8778e81fd3d3332c8038c1ce2336813d176a89a43bab3af1


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

android-webview-nexus5X
chromium-rel-win7-gpu-nvidia
linux-perf

📍 Pinpoint job started.
https://pinpoint-dot-chromeperf.appspot.com/job/12ed0f94240000

📍 Pinpoint job started.
https://pinpoint-dot-chromeperf.appspot.com/job/14d5438c240000

😿 Pinpoint job stopped with an error.
https://pinpoint-dot-chromeperf.appspot.com/job/12ed0f94240000

__init__() got an unexpected keyword argument 'scope'

😿 Pinpoint job stopped with an error.
https://pinpoint-dot-chromeperf.appspot.com/job/14d5438c240000

__init__() got an unexpected keyword argument 'scope'

📍 Pinpoint job started.
https://pinpoint-dot-chromeperf.appspot.com/job/14f9e702240000

📍 Pinpoint job started.
https://pinpoint-dot-chromeperf.appspot.com/job/14e9be22240000

😿 Pinpoint job stopped with an error.
https://pinpoint-dot-chromeperf.appspot.com/job/14e9be22240000

All of the attempts failed. See the individual attempts for details on each error.

📍 Found a significant difference after 1 commit.
https://pinpoint-dot-chromeperf.appspot.com/job/14f9e702240000

[oilpan] Cleanup tracing scopes by mlippautz@chromium.org
https://chromium.googlesource.com/chromium/src/+/c6ff060cc760c7cb8a44be7314ce5e96757213c6

Understanding performance regressions:
  http://g.co/ChromePerformanceRegressions

📍 Pinpoint job started.
https://pinpoint-dot-chromeperf.appspot.com/job/14b1d1dc240000

I have a hard time believing that my Oilpan CL cleaning up scope usage caused this. The CL only deals with "BlinkGC." prefixed metrics.

Looking at one of the graphs in more detail, we do way more full GCs, 5 instead of 1.

https://chromeperf.appspot.com/report?sid=35f1260125e5edb7a77812bb4811cebb86b121ad4ddcd7f6cb944894c41b3401

Kicked off another bisect.

📍 Found a significant difference after 1 commit.
https://pinpoint-dot-chromeperf.appspot.com/job/14b1d1dc240000

[oilpan] Cleanup tracing scopes by mlippautz@chromium.org
https://chromium.googlesource.com/chromium/src/+/c6ff060cc760c7cb8a44be7314ce5e96757213c6

Understanding performance regressions:
  http://g.co/ChromePerformanceRegressions

Looks like pinpoint is broken. The build at your CL failed (SwarmingTestError: The swarming task 3da40d31b4228410 failed. The test exited with code 1.). Somehow it then thinks it found a significant different.

Opened https://github.com/catapult-project/catapult/issues/4483.

I can improve the wording of the bug comment. Pinpoint is indicating here that this CL caused the test to start failing, and thus the performance bisection can't continue.

Was there also a commit that fixed the test? We can run another job with that patch applied to the job to further narrow down the regression.

Assigning for response to #15, feel free to orphan again afterwards.

There was an issue where tracing scopes have not been closed properly. This was fixed in https://chromium-review.googlesource.com/c/chromium/src/+/1065723. The graphs also recovered.