Android: fix cpu governor setup for perf tests

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 bec92a20d2a1bcb308322ba658d08b5c7e304692..80f80d44ffdbf5eeca1af4cf5018f75681201fe1 100644
--- a/build/android/pylib/perf_tests_helper.py
+++ b/build/android/pylib/perf_tests_helper.py
@@ -130,10 +130,10 @@ class PerfTestSetup(object):
 
   def __init__(self, adb):
     self._adb = adb
-    num_cpus = self._adb.GetFileContents('/sys/devices/system/cpu/online',
+    kernel_max = self._adb.GetFileContents('/sys/devices/system/cpu/kernel_max',
                                          log_result=False)
-    assert num_cpus, 'Unable to find /sys/devices/system/cpu/online'
-    self._num_cpus = int(num_cpus[0].split('-')[-1])
+    assert kernel_max, 'Unable to find /sys/devices/system/cpu/kernel_max'
+    self._kernel_max = int(kernel_max[0])
     self._original_scaling_governor = None
 
   def DropRamCaches(self):
@@ -159,6 +159,8 @@ class PerfTestSetup(object):
     self._original_scaling_governor = None
 
   def _SetScalingGovernorInternal(self, value):
-    for cpu in range(self._num_cpus):
-      self._adb.RunShellCommand(
-          ('echo %s > ' + PerfTestSetup._SCALING_GOVERNOR) % (value, cpu))
+    for cpu in range(self._kernel_max + 1):
+      scaling_governor = PerfTestSetup._SCALING_GOVERNOR % cpu

[bulach, 2013/01/16 09:34:15]

hehe, probably best to:
scaling_governor_file = PerfTestSetup._SCALING_GOVERNOR_FMT % cpu

that is, add suffixes for "_file" and "_FMT".
the ambiguous format / mod operation got me wondering... :)

+      if self._adb.Adb().DoesFileExist(scaling_governor):
+        self._adb.RunShellCommand(
+            ('echo %s > ' + scaling_governor) % value)