Introduce a dynamic process pool for the local test driver

tools/testrunner/local/execution.py

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 # (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
 # OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 
 
-import multiprocessing
 import os
-import threading
 import time
 
+from pool import Pool
 from . import commands
 from . import utils
 
 
-BREAK_NOW = -1
-EXCEPTION = -2
-
-
 class Job(object):
   def __init__(self, command, dep_command, test_id, timeout, verbose):
     self.command = command
     self.dep_command = dep_command
     self.id = test_id
     self.timeout = timeout
     self.verbose = verbose
 
 
 def RunTest(job):
-  try:
-    start_time = time.time()
-    if job.dep_command is not None:
-      dep_output = commands.Execute(job.dep_command, job.verbose, job.timeout)
-      # TODO(jkummerow): We approximate the test suite specific function
-      # IsFailureOutput() by just checking the exit code here. Currently
-      # only cctests define dependencies, for which this simplification is
-      # correct.
-      if dep_output.exit_code != 0:
-        return (job.id, dep_output, time.time() - start_time)
-    output = commands.Execute(job.command, job.verbose, job.timeout)
-    return (job.id, output, time.time() - start_time)
-  except KeyboardInterrupt:
-    return (-1, BREAK_NOW, 0)
-  except Exception, e:
-    print(">>> EXCEPTION: %s" % e)
-    return (-1, EXCEPTION, 0)
-
+  start_time = time.time()
+  if job.dep_command is not None:
+    dep_output = commands.Execute(job.dep_command, job.verbose, job.timeout)
+    # TODO(jkummerow): We approximate the test suite specific function
+    # IsFailureOutput() by just checking the exit code here. Currently
+    # only cctests define dependencies, for which this simplification is
+    # correct.
+    if dep_output.exit_code != 0:
+      return (job.id, dep_output, time.time() - start_time)
+  output = commands.Execute(job.command, job.verbose, job.timeout)
+  return (job.id, output, time.time() - start_time)
 
 class Runner(object):
 
   def __init__(self, suites, progress_indicator, context):
     self.tests = [ t for s in suites for t in s.tests ]
     self._CommonInit(len(self.tests), progress_indicator, context)
 
   def _CommonInit(self, num_tests, progress_indicator, context):
     self.indicator = progress_indicator
     progress_indicator.runner = self
     self.context = context
     self.succeeded = 0
     self.total = num_tests
     self.remaining = num_tests
     self.failed = []
     self.crashed = 0
-    self.terminate = False
-    self.lock = threading.Lock()
 
   def Run(self, jobs):
     self.indicator.Starting()
     self._RunInternal(jobs)
     self.indicator.Done()
     if self.failed or self.remaining:
       return 1
     return 0
 
   def _RunInternal(self, jobs):
-    pool = multiprocessing.Pool(processes=jobs)
+    pool = Pool(jobs)
     test_map = {}
+    # TODO(machenbach): Instead of filling the queue completely before
+    # pool.imap_unordered, make this a generator that already starts testing
+    # while the queue is filled.

[Jakob Kummerow, 2014/05/14 09:07:37]

Have you measured whether that would make a difference? Otherwise let's drop the
plan and the TODO.

[Michael Achenbach, 2014/05/14 12:05:58]

It takes 0.5 seconds... I rather leave the todo and make a measurement in a
follow up CL if this can be improved. If not, I'll remove the todo.

     queue = []
     queued_exception = None
     for test in self.tests:
       assert test.id >= 0
       test_map[test.id] = test
       try:
         command = self.GetCommand(test)
       except Exception, e:
         # If this failed, save the exception and re-raise it later (after
         # all other tests have had a chance to run).
         queued_exception = e
         continue
       timeout = self.context.timeout
       if ("--stress-opt" in test.flags or
           "--stress-opt" in self.context.mode_flags or
           "--stress-opt" in self.context.extra_flags):
         timeout *= 4
       if test.dependency is not None:
         dep_command = [ c.replace(test.path, test.dependency) for c in command ]
       else:
         dep_command = None
       job = Job(command, dep_command, test.id, timeout, self.context.verbose)
-      queue.append(job)
+      queue.append([job])
     try:
-      kChunkSize = 1
-      it = pool.imap_unordered(RunTest, queue, kChunkSize)
+      it = pool.imap_unordered(RunTest, queue)
       for result in it:
-        test_id = result[0]
-        if test_id < 0:
-          if result[1] == BREAK_NOW:
-            self.terminate = True
-          else:
-            continue
-        if self.terminate:
-          pool.terminate()
-          pool.join()
-          raise BreakNowException("User pressed Ctrl+C or IO went wrong")
-        test = test_map[test_id]
+        test = test_map[result[0]]
         self.indicator.AboutToRun(test)
         test.output = result[1]
         test.duration = result[2]
         has_unexpected_output = test.suite.HasUnexpectedOutput(test)
         if has_unexpected_output:
           self.failed.append(test)
           if test.output.HasCrashed():
             self.crashed += 1
         else:
           self.succeeded += 1
         self.remaining -= 1
         self.indicator.HasRun(test, has_unexpected_output)
-    except KeyboardInterrupt:
+    finally:
       pool.terminate()
-      pool.join()
-      raise
-    except Exception, e:
-      print("Exception: %s" % e)
-      pool.terminate()
-      pool.join()
-      raise
     if queued_exception:
       raise queued_exception
-    return
 
 
   def GetCommand(self, test):
     d8testflag = []
     shell = test.suite.shell()
     if shell == "d8":
       d8testflag = ["--test"]
     if utils.IsWindows():
       shell += ".exe"
     cmd = (self.context.command_prefix +
            [os.path.abspath(os.path.join(self.context.shell_dir, shell))] +
            d8testflag +
            ["--random-seed=%s" % self.context.random_seed] +
            test.suite.GetFlagsForTestCase(test, self.context) +
            self.context.extra_flags)
     return cmd
 
 
 class BreakNowException(Exception):
   def __init__(self, value):
     self.value = value
   def __str__(self):
     return repr(self.value)