This CL updates the parallel job library in the au test harness to be more robust.

au_test_harness/vm_au_worker.py

 # Copyright (c) 2011 The Chromium OS Authors. All rights reserved.
 # Use of this source code is governed by a BSD-style license that can be
 # found in the LICENSE file.
 
 """Module containing implementation of an au_worker for virtual machines."""
 
 import os
-import threading
 import unittest
 
 import cros_build_lib as cros_lib
 
 import au_worker
 
 
 class VMAUWorker(au_worker.AUWorker):
   """Test harness for updating virtual machines."""
 
-  # Class variables used to acquire individual VM variables per test.
-  _vm_lock = threading.Lock()
-  _next_port = 9222
-
   def __init__(self, options, test_results_root):
     """Processes vm-specific options."""
     au_worker.AUWorker.__init__(self, options, test_results_root)
     self.graphics_flag = ''
     if options.no_graphics: self.graphics_flag = '--no_graphics'
     if not self.board: cros_lib.Die('Need board to convert base image to vm.')
 
-    self._AcquireUniquePortAndPidFile()
-    self._KillExistingVM(self._kvm_pid_file)
-
   def _KillExistingVM(self, pid_file):
     """Kills an existing VM specified by the pid_file."""
     if os.path.exists(pid_file):
       cros_lib.Warning('Existing %s found.  Deleting and killing process' %
                        pid_file)
       cros_lib.RunCommand(['./cros_stop_vm', '--kvm_pid=%s' % pid_file],
                           cwd=self.crosutilsbin)
 
     assert not os.path.exists(pid_file)
 
-  def _AcquireUniquePortAndPidFile(self):
-    """Acquires unique ssh port and pid file for VM."""
-    with VMAUWorker._vm_lock:
-      self._ssh_port = VMAUWorker._next_port
-      self._kvm_pid_file = '/tmp/kvm.%d' % self._ssh_port
-      VMAUWorker._next_port += 1
-
   def CleanUp(self):
     """Stop the vm after a test."""
     self._KillExistingVM(self._kvm_pid_file)
 
   def PrepareBase(self, image_path):
     """Creates an update-able VM based on base image."""
     self.PrepareVMBase(image_path)
 
   def UpdateImage(self, image_path, src_image_path='', stateful_change='old',
                   proxy_port='', private_key_path=None):
@@ skipping 52 matching lines @@
                        '--results_dir_root=%s' % log_directory_in_chroot,
                        self.verify_suite,
                       ]
     if self.graphics_flag: commandWithArgs.append(self.graphics_flag)
     output = cros_lib.RunCommand(commandWithArgs, error_ok=True,
                                  enter_chroot=False, redirect_stdout=True,
                                  cwd=self.crosutilsbin)
     return self.AssertEnoughTestsPassed(unittest, output,
                                         percent_required_to_pass)