2 files changed, 16 insertions, 11 deletions
diff --git a/Lib/concurrent/futures/_base.py b/Lib/concurrent/futures/_base.py
index 79b91d4..6cfded3 100644
--- a/Lib/concurrent/futures/_base.py
+++ b/Lib/concurrent/futures/_base.py
@@ -536,15 +536,19 @@ class Executor(object):
 
         fs = [self.submit(fn, *args) for args in zip(*iterables)]
 
-        try:
-            for future in fs:
-                if timeout is None:
-                    yield future.result()
-                else:
-                    yield future.result(end_time - time.time())
-        finally:
-            for future in fs:
-                future.cancel()
+        # Yield must be hidden in closure so that the futures are submitted
+        # before the first iterator value is required.
+        def result_iterator():
+            try:
+                for future in fs:
+                    if timeout is None:
+                        yield future.result()
+                    else:
+                        yield future.result(end_time - time.time())
+            finally:
+                for future in fs:
+                    future.cancel()
+        return result_iterator()
 
     def shutdown(self, wait=True):
         """Clean-up the resources associated with the Executor.
diff --git a/Lib/concurrent/futures/process.py b/Lib/concurrent/futures/process.py
index ff566d3..f0bf6d5 100644
--- a/Lib/concurrent/futures/process.py
+++ b/Lib/concurrent/futures/process.py
@@ -49,6 +49,7 @@ import atexit
 from concurrent.futures import _base
 import queue
 import multiprocessing
+from multiprocessing.queues import SimpleQueue
 import threading
 import weakref
 
@@ -204,7 +205,7 @@ def _queue_management_worker(executor_reference,
                                 work_ids_queue,
                                 call_queue)
 
-        result_item = result_queue.get(block=True)
+        result_item = result_queue.get()
         if result_item is not None:
             work_item = pending_work_items[result_item.work_id]
             del pending_work_items[result_item.work_id]
@@ -284,7 +285,7 @@ class ProcessPoolExecutor(_base.Executor):
         # because futures in the call queue cannot be cancelled.
         self._call_queue = multiprocessing.Queue(self._max_workers +
                                                  EXTRA_QUEUED_CALLS)
-        self._result_queue = multiprocessing.Queue()
+        self._result_queue = SimpleQueue()
         self._work_ids = queue.Queue()
         self._queue_management_thread = None
         self._processes = set()