Fix last_devices to be quieter, and improve device affinity.

build/android/pylib/perf/test_runner.py

Index: build/android/pylib/perf/test_runner.py
diff --git a/build/android/pylib/perf/test_runner.py b/build/android/pylib/perf/test_runner.py
index 991fc003049152246d89d15f290b88c8c1b228c9..dc86d3629e92f3317ea1d939140743d6988099d5 100644
--- a/build/android/pylib/perf/test_runner.py
+++ b/build/android/pylib/perf/test_runner.py
@@ -66,6 +66,8 @@ from pylib.base import base_test_runner
 from pylib.device import battery_utils
 from pylib.device import device_errors
 
+NUM_DEVICE_AFFINITIES = 8
+
 
 def GetPersistedResult(test_name):
   file_name = os.path.join(constants.PERF_OUTPUT_DIR, test_name)
@@ -173,22 +175,19 @@ class _HeartBeatLogger(object):
 
 
 class TestRunner(base_test_runner.BaseTestRunner):
-  def __init__(self, test_options, device, shard_index, max_shard, tests,
-      flaky_tests):
+  def __init__(self, test_options, device, affinities, tests, flaky_tests):
     """A TestRunner instance runs a perf test on a single device.
 
     Args:
       test_options: A PerfOptions object.
       device: Device to run the tests.
-      shard_index: the index of this device.
-      max_shards: the maximum shard index.
+      affinities: the list of affinities to run on this shard.
       tests: a dict mapping test_name to command.
       flaky_tests: a list of flaky test_name.
     """
     super(TestRunner, self).__init__(device, None)
     self._options = test_options
-    self._shard_index = shard_index
-    self._max_shard = max_shard
+    self._affinities = affinities
     self._tests = tests
     self._flaky_tests = flaky_tests
     self._output_dir = None
@@ -215,12 +214,14 @@ class TestRunner(base_test_runner.BaseTestRunner):
 
   def _CheckDeviceAffinity(self, test_name):
     """Returns True if test_name has affinity for this shard."""
-    affinity = (self._tests['steps'][test_name]['device_affinity'] %
-                self._max_shard)
-    if self._shard_index == affinity:
+    affinity = self._tests['steps'][test_name]['device_affinity']
+    if not (0 <= affinity and affinity < NUM_DEVICE_AFFINITIES):
+      raise Exception('Got out-of-range device affinity %s' % affinity)
+    if affinity in self._affinities:
       return True
-    logging.info('Skipping %s on %s (affinity is %s, device is %s)',
-                 test_name, self.device_serial, affinity, self._shard_index)
+    logging.info(
+        'Skipping %s on %s (affinity is %s, allowed affinities are %s)',
+                 test_name, self.device_serial, affinity, self._affinities)
     return False
 
   def _CleanupOutputDirectory(self):