diff -r 000000000000 -r 6474c204b198 js/src/tests/lib/tasks_win.py
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/js/src/tests/lib/tasks_win.py	Wed Dec 31 06:09:35 2014 +0100
@@ -0,0 +1,89 @@
+# Multiprocess activities with a push-driven divide-process-collect model.
+
+from threading import Thread, Lock
+from Queue import Queue, Empty
+from datetime import datetime
+
+class Source:
+    def __init__(self, task_list, results, timeout, verbose = False):
+        self.tasks = Queue()
+        for task in task_list:
+            self.tasks.put_nowait(task)
+
+        self.results = results
+        self.timeout = timeout
+        self.verbose = verbose
+
+    def start(self, worker_count):
+        t0 = datetime.now()
+
+        sink = Sink(self.results)
+        self.workers = [ Worker(_+1, self.tasks, sink, self.timeout, self.verbose) for _ in range(worker_count) ]
+        if self.verbose: print '[P] Starting workers.'
+        for w in self.workers:
+            w.t0 = t0
+            w.start()
+        ans = self.join_workers()
+        if self.verbose: print '[P] Finished.'
+        return ans
+
+    def join_workers(self):
+        try:
+            for w in self.workers:
+                w.join(20000)
+            return True
+        except KeyboardInterrupt:
+            for w in self.workers:
+                w.stop = True
+            return False
+
+class Sink:
+    def __init__(self, results):
+        self.results = results
+        self.lock = Lock()
+
+    def push(self, result):
+        self.lock.acquire()
+        try:
+            self.results.push(result)
+        finally:
+            self.lock.release()
+
+class Worker(Thread):
+    def __init__(self, id, tasks, sink, timeout, verbose):
+        Thread.__init__(self)
+        self.setDaemon(True)
+        self.id = id
+        self.tasks = tasks
+        self.sink = sink
+        self.timeout = timeout
+        self.verbose = verbose
+
+        self.thread = None
+        self.stop = False
+
+    def log(self, msg):
+        if self.verbose:
+            dd = datetime.now() - self.t0
+            dt = dd.seconds + 1e-6 * dd.microseconds
+            print '[W%d %.3f] %s' % (self.id, dt, msg)
+
+    def run(self):
+        try:
+            while True:
+                if self.stop:
+                    break
+                self.log('Get next task.')
+                task = self.tasks.get(False)
+                self.log('Start task %s.'%str(task))
+                result = task.run(task.js_cmd_prefix, self.timeout)
+                self.log('Finished task.')
+                self.sink.push(result)
+                self.log('Pushed result.')
+        except Empty:
+            pass
+
+def run_all_tests(tests, results, options):
+    pipeline = Source(tests, results, options.timeout, False)
+    return pipeline.start(options.worker_count)
+