From: Antoine Pitrou <solipsis@pitrou.net>
Date: Wed, 2 Jun 2010 17:08:47 +0000 (+0000)
Subject: Issue #8873: add a documentation note about possible performance issues with the
X-Git-Tag: v2.7rc1~50
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=c395545a4ab4b4760c0472af74f526f405389864;p=thirdparty%2FPython%2Fcpython.git

Issue #8873: add a documentation note about possible performance issues with the
default of unbuffered IO in subprocess.Popen.
---

diff --git a/Doc/library/subprocess.rst b/Doc/library/subprocess.rst
index 19a8b6b82605..b5e769cab596 100644
--- a/Doc/library/subprocess.rst
+++ b/Doc/library/subprocess.rst
@@ -94,6 +94,12 @@ 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,