telemetry: Fix killing the perf profiler

build/android/pylib/device/device_utils.py

Index: build/android/pylib/device/device_utils.py
diff --git a/build/android/pylib/device/device_utils.py b/build/android/pylib/device/device_utils.py
index f201ef36b8bf04fa20881109d11c6225f8322bfb..6bed403a81883f73b4660297e1a1af24628ee2dc 100644
--- a/build/android/pylib/device/device_utils.py
+++ b/build/android/pylib/device/device_utils.py
@@ -736,7 +736,8 @@ class DeviceUtils(object):
       CommandTimeoutError on timeout.
       DeviceUnreachableError on missing device.
     """
-    pids = self.GetPids(process_name)
+    pids = self.GetPids(process_name, multiple_instances=True)
+    pids = [pid for instances in pids.values() for pid in instances]
     if not pids:
       if quiet:
         return 0
@@ -744,13 +745,13 @@ class DeviceUtils(object):
         raise device_errors.CommandFailedError(
             'No process "%s"' % process_name, str(self))
 
-    cmd = ['kill', '-%d' % signum] + pids.values()
+    cmd = ['kill', '-%d' % signum] + pids
     self.RunShellCommand(cmd, as_root=as_root, check_return=True)
 
     if blocking:
       # TODO(perezu): use timeout_retry.WaitFor
       wait_period = 0.1
-      while self.GetPids(process_name):
+      while self.GetPids(process_name, multiple_instances=True):
         time.sleep(wait_period)
 
     return len(pids)
@@ -1565,7 +1566,8 @@ class DeviceUtils(object):
     return self.GetProp('ro.product.cpu.abi')
 
   @decorators.WithTimeoutAndRetriesFromInstance()
-  def GetPids(self, process_name, timeout=None, retries=None):
+  def GetPids(self, process_name, timeout=None, retries=None,
+              multiple_instances=False):

[perezju, 2015/07/24 14:03:10]

I don't think John will like adding an extra option (maybe he will prove me
wrong?), and it leads to a somewhat messy implementation.

I propose having a GetProcessPidPairs (or something more artfully named), with
essentially the same implementation as the current GetPids, but returning a list
of (binary_name, pid) pairs.

The implementation of GetPids would then just become:

  return dict(self.GetProcessPidPairs(...))

so we don't change the expectations of existing callers, and KillAll can use the
GetProcessPidPairs to really kill all matching processes.

[Sami, 2015/07/24 14:36:40]

Yeah I wasn't super happy about the flag either. Thanks for the great idea --
I'm stealing it :)

     """Returns the PIDs of processes with the given name.
 
     Note that the |process_name| is often the package name.
@@ -1574,16 +1576,20 @@ class DeviceUtils(object):
       process_name: A string containing the process name to get the PIDs for.
       timeout: timeout in seconds
       retries: number of retries
+      multiple_instances: Whether or not multiple instances of the same process
+          binary are supported. If True, the returned dict will have a list of
+          PIDs for each found process. If False, only a single matching PID
+          will be returned for each process.
 
     Returns:
-      A dict mapping process name to PID for each process that contained the
-      provided |process_name|.
+      A dict mapping process name to PID (or list of PIDs) for each process
+      that contained the provided |process_name|.
 
     Raises:
       CommandTimeoutError on timeout.
       DeviceUnreachableError on missing device.
     """
-    procs_pids = {}
+    procs_pids = collections.defaultdict(list) if multiple_instances else {}
     try:
       ps_output = self._RunPipedShellCommand(
           'ps | grep -F %s' % cmd_helper.SingleQuote(process_name))
@@ -1599,7 +1605,11 @@ class DeviceUtils(object):
       try:
         ps_data = line.split()
         if process_name in ps_data[-1]:
-          procs_pids[ps_data[-1]] = ps_data[1]
+          binary_name = ps_data[-1]
+          if multiple_instances:
+            procs_pids[binary_name].append(ps_data[1])
+          else:
+            procs_pids[binary_name] = ps_data[1]
       except IndexError:
         pass
     return procs_pids