Saw this in the log, might be relevant.

Exception raised when cleaning story run: 

Traceback (most recent call last):
  _RunStoryAndProcessErrorIfNeeded at /b/build/slave/Android_Nexus6_Perf__1_/build/src/third_party/catapult/telemetry/telemetry/internal/story_runner.py:109
    test.DidRunPage(state.platform)
  DidRunPage at /b/build/slave/Android_Nexus6_Perf__1_/build/src/tools/perf/measurements/smoothness.py:66
    self._tbm.DidRunStory(platform)
  DidRunStory at /b/build/slave/Android_Nexus6_Perf__1_/build/src/third_party/catapult/telemetry/telemetry/web_perf/timeline_based_measurement.py:300
    platform.tracing_controller.StopTracing()
  StopTracing at /b/build/slave/Android_Nexus6_Perf__1_/build/src/third_party/catapult/telemetry/telemetry/core/tracing_controller.py:47
    return self._tracing_controller_backend.StopTracing()
  StopTracing at /b/build/slave/Android_Nexus6_Perf__1_/build/src/third_party/catapult/telemetry/telemetry/internal/platform/tracing_controller_backend.py:108
    self._IssueClockSyncMarker()
  _IssueClockSyncMarker at /b/build/slave/Android_Nexus6_Perf__1_/build/src/third_party/catapult/telemetry/telemetry/internal/platform/tracing_controller_backend.py:199
    self._RecordIssuerClockSyncMarker)
  RecordClockSyncMarker at /b/build/slave/Android_Nexus6_Perf__1_/build/src/third_party/catapult/telemetry/telemetry/internal/platform/tracing_agent/chrome_tracing_agent.py:183
    sync_id, record_controller_clock_sync_marker_callback)
  _RecordClockSyncMarkerAsyncEvent at /b/build/slave/Android_Nexus6_Perf__1_/build/src/third_party/catapult/telemetry/telemetry/internal/platform/tracing_agent/chrome_tracing_agent.py:166
    raise ChromeClockSyncError()
ChromeClockSyncError

Locals:
  has_clock_synced                             : False
  record_controller_clock_sync_marker_callback : <bound method TracingControllerBackend._RecordIssuerClockSyncMarker of <telemetry.internal.platform.tracing_controller_backend.TracingControllerBackend object at 0x7fc0083c63d0>>
  sync_id                                      : '4cad5991-5099-460c-bd16-e02e3d640a5a'

Bisect: https://build.chromium.org/p/tryserver.chromium.perf/builders/android_nexus6_perf_bisect/builds/2275 (eventually)

The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/673177ca596cdfe612aa8c2c53aaa1b0b0f175b8

commit 673177ca596cdfe612aa8c2c53aaa1b0b0f175b8
Author: simonhatch <simonhatch@chromium.org>
Date: Tue Jun 28 21:52:52 2016

Disable smoothness.tough_filters_cases on Nexus 6.

TBR=sullivan@chromium.org
BUG= 624032 
CQ_EXTRA_TRYBOTS=tryserver.chromium.perf:android_s5_perf_cq;tryserver.chromium.perf:mac_retina_perf_cq

Review-Url: https://codereview.chromium.org/2100403003
Cr-Commit-Position: refs/heads/master@{#402557}

[modify] https://crrev.com/673177ca596cdfe612aa8c2c53aaa1b0b0f175b8/tools/perf/benchmarks/smoothness.py

Try again: https://build.chromium.org/p/tryserver.chromium.perf/builders/android_nexus6_perf_bisect/builds/2288

===== BISECT JOB RESULTS =====
Status: completed


===== TESTED REVISIONS =====
Revision         Exit Code  Std Dev  N   Good?
chromium@401595  0          N/A      10  good
chromium@401824  0          N/A      10  bad

Bisect job ran on: android_nexus6_perf_bisect
Bug ID: 624032

Test Command: src/tools/perf/run_benchmark -v --browser=android-chromium --output-format=chartjson --upload-results --also-run-disabled-tests smoothness.tough_filters_cases
Test Metric: frame_times/frame_times
Relative Change: 0.00%
Score: 0

Buildbot stdio: http://build.chromium.org/p/tryserver.chromium.perf/builders/android_nexus6_perf_bisect/builds/2288
Job details: https://chromeperf.appspot.com/buildbucket_job_status/9007961465069306480


Not what you expected? We'll investigate and get back to you!
  https://chromeperf.appspot.com/bad_bisect?try_job_id=5844363230314496

| O O | Visit http://www.chromium.org/developers/speed-infra/perf-bug-faq
|  X  | for more information addressing perf regression bugs. For feedback,
| / \ | file a bug with component Tests>AutoBisect.  Thank you!

Perf sheriff... This is now green.

Marking as fixed.

The bot is only green because the tests are still disabled on Nexus 6. This bug is about re-enabling them.

https://cs.chromium.org/chromium/src/tools/perf/benchmarks/smoothness.py?q=%22Nexus+6%22&sq=package:chromium&l=75&dr=C

senorblanco, is there someone this could be assigned to? 

Assign to senorblanco@ since you are the benchmark owner. 

The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/e41e32350fdb7030a0ec1a786be6439226f8427e

commit e41e32350fdb7030a0ec1a786be6439226f8427e
Author: Sunny Sachanandani <sunnyps@chromium.org>
Date: Fri Nov 17 11:15:23 2017

Reenable smoothness.tough_filters_cases on Nexus 6.

This was disabled due to what looks like a telemetry issue at the time.
In any case, disabling the entire benchmark is not compatible with the
plan for merging all smoothness page sets. Local testing on Nexus 6
indicates that this benchmark is fine.

R=nednguyen
BUG= 624032 ,760553

Change-Id: I6ab268ffbf0a8251844da0d7cdcf6841013356df
Reviewed-on: https://chromium-review.googlesource.com/776215
Commit-Queue: Ned Nguyen <nednguyen@google.com>
Reviewed-by: Ned Nguyen <nednguyen@google.com>
Cr-Commit-Position: refs/heads/master@{#517375}
[modify] https://crrev.com/e41e32350fdb7030a0ec1a786be6439226f8427e/tools/perf/benchmarks/smoothness.py