Eliminate uses of Queue.

Causes serious contention/slowdown as was currently used. Using
explicit locks and shared resources scales a lot better locally.

gtest-parallel

diff --git a/gtest-parallel b/gtest-parallel
index 7a2d423..58affcb 100755
--- a/gtest-parallel
+++ b/gtest-parallel
@@ -12,13 +12,13 @@
 # WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 # See the License for the specific language governing permissions and
 # limitations under the License.
-import Queue
 import optparse
 import subprocess
 import sys
 import threading
 import time
 
+stdout_lock = threading.Lock()
 class FilterFormat:
   total_tests = 0
   finished_tests = 0
@@ -50,35 +50,35 @@
           print line
     elif command == "TESTCNT":
       self.total_tests = int(arg.split(' ', 1)[1])
+      print "[0/%d] Running tests...\r" % self.total_tests,
 
   def add_stdout(self, job_id, output):
     self.outputs[job_id].append(output)
 
-  def log(self):
-    print "[0/?] Running tests...\r",
-    while True:
-      line = log.get()
-      if line == "":
-        break
-      (prefix, output) = line.split(' ', 1)
+  def log(self, line):
+    stdout_lock.acquire()
+    (prefix, output) = line.split(' ', 1)
 
-      if prefix[-1] == ':':
-        self.handle_meta(int(prefix[:-1]), output)
-      else:
-        self.add_stdout(int(prefix[:-1]), output)
+    if prefix[-1] == ':':
+      self.handle_meta(int(prefix[:-1]), output)
+    else:
+      self.add_stdout(int(prefix[:-1]), output)
+    stdout_lock.release()
+
+  def end(self):
     if self.failures:
       print "FAILED TESTS (%d/%d):" % (len(self.failures), self.total_tests)
       for (binary, test) in self.failures:
         print " ", binary + ": " + test
 
 class RawFormat:
-  def log(self):
-    while True:
-      line = log.get()
-      if line == "":
-        return
-      sys.stdout.write(line + "\n")
-      sys.stdout.flush()
+  def log(self, line):
+    stdout_lock.acquire()
+    sys.stdout.write(line + "\n")
+    sys.stdout.flush()
+    stdout_lock.release()
+  def end(self):
+    pass
 
 parser = optparse.OptionParser(
     usage = 'usage: %prog [options] executable [executable ...]')
@@ -138,14 +138,12 @@
 
 # Repeat tests (-r flag).
 tests *= options.repeat
-
-log = Queue.Queue()
-test_queue = Queue.Queue()
+test_lock = threading.Lock()
+job_id = 0
+logger.log(str(-1) + ': TESTCNT ' + ' ' + str(len(tests)))
 
 exit_code = 0
 def run_job((command, job_id, test)):
-  if test == '':
-    raise Queue.Empty
   begin = time.time()
   sub = subprocess.Popen(command + ['--gtest_filter=' + test] +
                            ['--gtest_color=' + options.gtest_color],
@@ -156,22 +154,29 @@
     line = sub.stdout.readline()
     if line == '':
       break
-    log.put(str(job_id) + '> ' + line.rstrip())
+    logger.log(str(job_id) + '> ' + line.rstrip())
 
   code = sub.wait()
   runtime_ms = int(1000 * (time.time() - begin))
-  log.put(str(job_id) + ': EXIT ' + str(code) + ' ' + str(runtime_ms))
+  logger.log(str(job_id) + ': EXIT ' + str(code) + ' ' + str(runtime_ms))
   if code != 0:
     global exit_code
     exit_code = code
 
 def worker():
+  global job_id
   while True:
-    try:
-      run_job(test_queue.get())
-      test_queue.task_done()
-    except Queue.Empty:
+    job = None
+    test_lock.acquire()
+    if job_id < len(tests):
+      (test_binary, command, test) = tests[job_id]
+      logger.log(str(job_id) + ': TEST ' + test_binary + ' ' + test)
+      job = (command, job_id, test)
+    job_id += 1
+    test_lock.release()
+    if job is None:
       return
+    run_job(job)
 
 def start_daemon(func):
   t = threading.Thread(target=func)
@@ -180,17 +185,7 @@
   return t
 
 workers = [start_daemon(worker) for i in range(options.workers)]
-printer = start_daemon(logger.log)
-
-log.put(str(-1) + ': TESTCNT ' + ' ' + str(len(tests)))
-for job_id, (test_binary, command, test) in enumerate(tests):
-  log.put(str(job_id) + ': TEST ' + test_binary + ' ' + test)
-  test_queue.put((command, job_id, test))
-
-# Signal to tell the workers to stop.
-[test_queue.put(('', '', '')) for i in range(options.workers)]
 
 [t.join() for t in workers]
-log.put("")
-printer.join()
+logger.end()
 sys.exit(exit_code)