@qyearsley, any idea of who would be best to look at this?

This failure might be related to some media.android.tough_video_cases failures.

It seems in the metrics/cpu.py script there can be an int overflow with the total_time variable. There seems to be a comment in the script to fix this. 

    # Fix overflow for 32-bit jiffie counter, 64-bit counter will not overflow.
    # Linux kernel starts with a value close to an overflow, so correction is
    # necessary.

The relevant code is here....

https://cs.chromium.org/chromium/src/tools/perf/metrics/cpu.py?type=cs&q=perf/metrics/cpu.py&sq=package:chromium&l=91
This code seems a big buggy. For instance, I think if the int overflows multiple times it just works incorrectly.

Below is the error we are hitting...

https://uberchromegw.corp.google.com/i/chromium.perf/builders/Android%20Nexus7v2%20Perf%20%282%29/builds/3445/steps/media.android.tough_video_cases/logs/stdio

Traceback (most recent call last):
  RunBenchmark at /b/rr/tmpqJGypr/w/src/third_party/catapult/telemetry/telemetry/internal/story_runner.py:343
    benchmark.ShouldTearDownStateAfterEachStorySetRun())
  Run at /b/rr/tmpqJGypr/w/src/third_party/catapult/telemetry/telemetry/internal/story_runner.py:229
    _RunStoryAndProcessErrorIfNeeded(story, results, state, test)
  _RunStoryAndProcessErrorIfNeeded at /b/rr/tmpqJGypr/w/src/third_party/catapult/telemetry/telemetry/internal/story_runner.py:87
    state.RunStory(results)
  traced_function at /b/rr/tmpqJGypr/w/src/third_party/catapult/common/py_trace_event/py_trace_event/trace_event_impl/decorators.py:52
    return func(*args, **kwargs)
  RunStory at /b/rr/tmpqJGypr/w/src/third_party/catapult/telemetry/telemetry/page/shared_page_state.py:301
    self._current_page, self._current_tab, results)
  traced_function at /b/rr/tmpqJGypr/w/src/third_party/catapult/common/py_trace_event/py_trace_event/trace_event_impl/decorators.py:52
    return func(*args, **kwargs)
  ValidateAndMeasurePage at /b/rr/tmpqJGypr/w/src/tools/perf/measurements/media.py:64
    self._cpu_metric.AddResults(tab, results, trace_name=trace_name)
  AddResults at /b/rr/tmpqJGypr/w/src/tools/perf/metrics/cpu.py:46
    cpu_stats = _SubtractCpuStats(self._stop_cpu, self._start_cpu)
  _SubtractCpuStats at /b/rr/tmpqJGypr/w/src/tools/perf/metrics/cpu.py:95
    'Expected total_time > 0, was: %d' % total_time)
AssertionError: Expected total_time > 0, was: 4252017631