Add a class for management of thermal throttling

build/android/pylib/perf_tests_helper.py

Index: build/android/pylib/perf_tests_helper.py
diff --git a/build/android/pylib/perf_tests_helper.py b/build/android/pylib/perf_tests_helper.py
index c0a3ee413d80d5ed924538d1ddab86b377ea4016..3986b089ff09352fb8b1f9feefdbe94b634bbf25 100644
--- a/build/android/pylib/perf_tests_helper.py
+++ b/build/android/pylib/perf_tests_helper.py
@@ -3,6 +3,7 @@
 # found in the LICENSE file.
 
 import re
+import logging
 
 import android_commands
 import math
@@ -118,3 +119,48 @@ class PerfTestSetup(object):
     for cpu in range(self._num_cpus):
       self._adb.RunShellCommand(
           ('echo %s > ' + PerfTestSetup._SCALING_GOVERNOR) % (value, cpu))
+
+
+class ThermalThrottle(object):

[bulach, 2012/10/31 10:44:47]

it'd make sense to have this class in its own file in this directory,
thermal_throttle.py

[Anthony Berent, 2012/10/31 15:14:02]

Done.

+  """Class to detect and track thermal throttling
+
+  Usage:
+    Wait for IsThrottled() to be False before running test
+    After running test call HasBeenThrottled() to find out if the
+    test run was affected by thermal throttling.
+
+    Currently assumes an OMap device, but I don't know of any others with

[bulach, 2012/10/31 10:44:47]

nit: people told me in the past to avoid using first person.. probably best to
just remove the last sentence and just keep "Assumes an OMap device." ? 

[Anthony Berent, 2012/10/31 15:14:02]

Done.

+    thermal throttling.
+  """
+  _throttled = False

[bulach, 2012/10/31 10:44:47]

nit: this should be a regular member in __init__ (afaict, here it's a static
member)

[Anthony Berent, 2012/10/31 15:14:02]

Done.

+
+  def __init__(self, adb):
+    self._adb = adb
+
+  def HasBeenThrottled(self):
+    """ True if there has been any throttling since the last call to
+        HasBeenThrottled or IsThrottled
+    """
+    return self._readLog()
+
+  def IsThrottled(self):
+    """True if currently throttled"""
+    self._readLog()
+    return self._throttled
+
+  def _readLog(self):

[bulach, 2012/10/31 10:44:47]

nit: _ReadLog

[Anthony Berent, 2012/10/31 15:14:02]

Done.

+    has_been_throttled = False
+    log = self._adb.RunShellCommand("dmesg -c")

[bulach, 2012/10/31 10:44:47]

nit: single quotes on all strings here.

[Anthony Berent, 2012/10/31 15:14:02]

Done.

+    for line in log:
+      if "omap_thermal_throttle" in line:
+        if not self._throttled:
+          logging.warning(">>> Thermally Throttled")
+        self._throttled = True
+        has_been_throttled = True
+      if "omap_thermal_unthrottle" in line:
+        if self._throttled:
+          logging.warning(">>> Thermally Unthrottled")
+        self._throttled = False
+        has_been_throttled = True
+    return has_been_throttled
+