[Telemetry] Add benchmark that doesn't launch chrome and collects platform data.

tools/perf/benchmarks/idle_platform.py

+# Copyright 2016 The Chromium Authors. All rights reserved.

[charliea (OOO until 10-5), 2017/03/20 14:20:25]

2017

[nednguyen, 2017/03/20 16:54:35]

this should be move to power.py file

[rnephew (Reviews Here), 2017/03/30 20:58:23]

Done.

+# Use of this source code is governed by a BSD-style license that can be
+# found in the LICENSE file.
+
+from core import perf_benchmark
+
+from telemetry.timeline import chrome_trace_category_filter
+from telemetry.web_perf import timeline_based_measurement
+import page_sets
+
+
+class IdlePlatformBenchmark(perf_benchmark.PerfBenchmark):
+  """Idle platform benchmark.
+
+  This benchmark just starts up tracing agents and lets the platform sit idle.

[charliea (OOO until 10-5), 2017/03/20 14:20:25]

Please include information about _why_ we want this benchmark. This is always
important, but especially important for this benchmark because I could see
pretty rational people thinking this is a dumb benchmark. (it's not)

[rnephew (Reviews Here), 2017/03/30 20:58:23]

Done.

+  """
+  def CreateTimelineBasedMeasurementOptions(self):
+    options = timeline_based_measurement.Options(
+        chrome_trace_category_filter.ChromeTraceCategoryFilter())
+    options.config.chrome_trace_config.category_filter.AddFilterString('rail')

[nednguyen, 2017/03/20 16:54:35]

we don't enable Chrome trace, so there is no use in adding chrome categories

[rnephew (Reviews Here), 2017/03/30 20:58:23]

Done.

+    options.config.enable_battor_trace = True
+    options.config.enable_cpu_trace = False

[charliea (OOO until 10-5), 2017/03/20 14:20:25]

Instead of options.config.enable_cpu_trace = False, which is the default, could
you please file a crbug against me to investigate the clock sync problem and
just add a TODO to enable the CPU trace?

[rnephew (Reviews Here), 2017/03/30 20:58:23]

https://github.com/catapult-project/catapult/issues/3463

+    options.config.enable_chrome_trace = False

[charliea (OOO until 10-5), 2017/03/20 14:20:25]

nit: no need to respecify the default

[rnephew (Reviews Here), 2017/03/30 20:58:23]

It actually is required. It was failing to clock sync chrome when I get rid of
htat line. Printing out the stack in the setter I determined it was getting
overwritten here:
https://cs.chromium.org/chromium/src/third_party/catapult/telemetry/telemetry...

+    # Atrace tracing agent autodetects if its android and only runs if it is.
+    options.config.enable_atrace_trace = True
+    options.SetTimelineBasedMetrics([
+        'clockSyncLatencyMetric',
+        'powerMetric',
+        'tracingMetric'
+    ])
+    return options
+
+  def CreateStorySet(self, options):
+    return page_sets.IdlePlatformPageSet()
+
+  @classmethod
+  def ShouldTearDownStateAfterEachStoryRun(cls):
+    return True
+
+  @classmethod
+  def Name(cls):
+    return 'idle_platform'