diff --git a/Lib/subprocess.py b/Lib/subprocess.py
index 368ba0e..f7361e1 100644
--- a/Lib/subprocess.py
+++ b/Lib/subprocess.py
@@ -371,6 +371,7 @@
             error = IOError
 else:
     import select
+    _has_poll = hasattr(select, 'poll')
     import errno
     import fcntl
     import pickle
@@ -383,6 +384,11 @@
 except:
     MAXFD = 256
 
+# When select or poll has indicated that the file is writable,
+# we can write up to _PIPE_BUF bytes without risk of blocking.
+# POSIX defines PIPE_BUF as >= 512.
+_PIPE_BUF = getattr(select, 'PIPE_BUF', 512)
+
 _active = []
 
 def _cleanup():
@@ -1173,19 +1179,103 @@
 
 
         def _communicate(self, input):
+            if self.stdin:
+                # Flush stdio buffer.  This might block, if the user has
+                # been writing to .stdin in an uncontrolled fashion.
+                self.stdin.flush()
+                if not input:
+                    self.stdin.close()
+
+            if _has_poll:
+                stdout, stderr = self._communicate_with_poll(input)
+            else:
+                stdout, stderr = self._communicate_with_select(input)
+
+            # All data exchanged.  Translate lists into strings.
+            if stdout is not None:
+                stdout = b''.join(stdout)
+            if stderr is not None:
+                stderr = b''.join(stderr)
+
+            # Translate newlines, if requested.
+            # This also turns bytes into strings.
+            if self.universal_newlines:
+                if stdout is not None:
+                    stdout = self._translate_newlines(stdout,
+                                                      self.stdout.encoding)
+                if stderr is not None:
+                    stderr = self._translate_newlines(stderr,
+                                                      self.stderr.encoding)
+
+            self.wait()
+            return (stdout, stderr)
+
+
+        def _communicate_with_poll(self, input):
+            stdout = None # Return
+            stderr = None # Return
+            fd2file = {}
+            fd2output = {}
+
+            poller = select.poll()
+            def register_and_append(file_obj, eventmask):
+                poller.register(file_obj.fileno(), eventmask)
+                fd2file[file_obj.fileno()] = file_obj
+
+            def close_unregister_and_remove(fd):
+                poller.unregister(fd)
+                fd2file[fd].close()
+                fd2file.pop(fd)
+
+            if self.stdin and input:
+                register_and_append(self.stdin, select.POLLOUT)
+
+            select_POLLIN_POLLPRI = select.POLLIN | select.POLLPRI
+            if self.stdout:
+                register_and_append(self.stdout, select_POLLIN_POLLPRI)
+                fd2output[self.stdout.fileno()] = stdout = []
+            if self.stderr:
+                register_and_append(self.stderr, select_POLLIN_POLLPRI)
+                fd2output[self.stderr.fileno()] = stderr = []
+
+            input_offset = 0
+            while fd2file:
+                try:
+                    ready = poller.poll()
+                except select.error as e:
+                    if e.args[0] == errno.EINTR:
+                        continue
+                    raise
+
+                # XXX Rewrite these to use non-blocking I/O on the
+                # file objects; they are no longer using C stdio!
+
+                for fd, mode in ready:
+                    if mode & select.POLLOUT:
+                        chunk = input[input_offset : input_offset + _PIPE_BUF]
+                        input_offset += os.write(fd, chunk)
+                        if input_offset >= len(input):
+                            close_unregister_and_remove(fd)
+                    elif mode & select_POLLIN_POLLPRI:
+                        data = os.read(fd, 4096)
+                        if not data:
+                            close_unregister_and_remove(fd)
+                        fd2output[fd].append(data)
+                    else:
+                        # Ignore hang up or errors.
+                        close_unregister_and_remove(fd)
+
+            return (stdout, stderr)
+
+
+        def _communicate_with_select(self, input):
             read_set = []
             write_set = []
             stdout = None # Return
             stderr = None # Return
 
-            if self.stdin:
-                # Flush stdio buffer.  This might block, if the user has
-                # been writing to .stdin in an uncontrolled fashion.
-                self.stdin.flush()
-                if input:
-                    write_set.append(self.stdin)
-                else:
-                    self.stdin.close()
+            if self.stdin and input:
+                write_set.append(self.stdin)
             if self.stdout:
                 read_set.append(self.stdout)
                 stdout = []
@@ -1206,10 +1296,7 @@
                 # file objects; they are no longer using C stdio!
 
                 if self.stdin in wlist:
-                    # When select has indicated that the file is writable,
-                    # we can write up to PIPE_BUF bytes without risk
-                    # blocking.  POSIX defines PIPE_BUF >= 512
-                    chunk = input[input_offset : input_offset + 512]
+                    chunk = input[input_offset : input_offset + _PIPE_BUF]
                     bytes_written = os.write(self.stdin.fileno(), chunk)
                     input_offset += bytes_written
                     if input_offset >= len(input):
@@ -1230,25 +1317,9 @@
                         read_set.remove(self.stderr)
                     stderr.append(data)
 
-            # All data exchanged.  Translate lists into strings.
-            if stdout is not None:
-                stdout = b"".join(stdout)
-            if stderr is not None:
-                stderr = b"".join(stderr)
-
-            # Translate newlines, if requested.
-            # This also turns bytes into strings.
-            if self.universal_newlines:
-                if stdout is not None:
-                    stdout = self._translate_newlines(stdout,
-                                                      self.stdout.encoding)
-                if stderr is not None:
-                    stderr = self._translate_newlines(stderr,
-                                                      self.stderr.encoding)
-
-            self.wait()
             return (stdout, stderr)
 
+
         def send_signal(self, sig):
             """Send a signal to the process
             """