From 5050bb2e50f4035040380489c2e1d16cd59d51fa Mon Sep 17 00:00:00 2001 From: Antoine Pitrou Date: Wed, 2 Jun 2010 17:11:32 +0000 Subject: [PATCH] Merged revisions 81654 via svnmerge from svn+ssh://pythondev@svn.python.org/python/branches/py3k ................ r81654 | antoine.pitrou | 2010-06-02 19:10:49 +0200 (mer., 02 juin 2010) | 10 lines Merged revisions 81652 via svnmerge from svn+ssh://pythondev@svn.python.org/python/trunk ........ r81652 | antoine.pitrou | 2010-06-02 19:08:47 +0200 (mer., 02 juin 2010) | 4 lines Issue #8873: add a documentation note about possible performance issues with the default of unbuffered IO in subprocess.Popen. ........ ................ --- Doc/library/subprocess.rst | 6 ++++++ 1 file changed, 6 insertions(+) diff --git a/Doc/library/subprocess.rst b/Doc/library/subprocess.rst index 834ec58bf95..2c395518e84 100644 --- a/Doc/library/subprocess.rst +++ b/Doc/library/subprocess.rst @@ -88,6 +88,12 @@ This module defines one class called :class:`Popen`: size. A negative *bufsize* means to use the system default, which usually means fully buffered. The default value for *bufsize* is :const:`0` (unbuffered). + .. note:: + + If you experience performance issues, it is recommended that you try to + enable buffering by setting *bufsize* to either -1 or a large enough + positive value (such as 4096). + The *executable* argument specifies the program to execute. It is very seldom needed: Usually, the program to execute is defined by the *args* argument. If ``shell=True``, the *executable* argument specifies which shell to use. On Unix,