diff -r adb6b029b102 Lib/subprocess.py
--- a/Lib/subprocess.py	Wed Mar 09 15:02:31 2016 +0100
+++ b/Lib/subprocess.py	Fri Mar 11 01:41:43 2016 +0200
@@ -669,7 +669,7 @@
                                      self.stderr)
 
 
-def run(*popenargs, input=None, timeout=None, check=False, **kwargs):
+def run(*popenargs, input=None, timeout=None, check=False, kill_group=False, **kwargs):
     """Run command with arguments and return a CompletedProcess instance.
 
     The returned instance will have attributes args, returncode, stdout and
@@ -704,12 +704,18 @@
         try:
             stdout, stderr = process.communicate(input, timeout=timeout)
         except TimeoutExpired:
-            process.kill()
+            if kill_group:
+                process.killpg()
+            else:
+                process.kill()
             stdout, stderr = process.communicate()
             raise TimeoutExpired(process.args, timeout, output=stdout,
                                  stderr=stderr)
         except:
-            process.kill()
+            if kill_group:
+                process.killpg()
+            else:
+                process.kill()
             process.wait()
             raise
         retcode = process.poll()
@@ -1779,3 +1785,8 @@
             """Kill the process with SIGKILL
             """
             self.send_signal(signal.SIGKILL)
+
+        def killpg(self):
+            """Kill the process group with SIGKILL
+            """
+            os.killpg(os.getpgid(self.pid), signal.SIGTERM)