[ python-Bugs-1552726 ] Python polls unecessarily every 0.1 when interactive

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Bugs item #1552726, was opened at 2006-09-05 14:42
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Category: Python Library
Group: None
Status: Open
Resolution: None
Priority: 5
Submitted By: Richard Boulton (richardb)
Assigned to: Nobody/Anonymous (nobody)
Summary: Python polls unecessarily every 0.1 when interactive

Initial Comment:
When python is running an interactive session, and is
idle, it calls "select" with a timeout of 0.1 seconds
repeatedly.  This is intended to allow PyOS_InputHook()
to be called every 0.1 seconds, but happens even if
PyOS_InputHook() isn't being used (ie, is NULL).

To reproduce:
 - start a python session
 - attach to it using strace -p PID
 - observe that python repeatedly

This isn't a significant problem, since it only affects
idle interactive python sessions and uses only a tiny
bit of CPU, but people are whinging about it (though
some appear to be doing so tongue-in-cheek) and it
would be nice to fix it.

The attached patch (against Python-2.5c1) modifies the
readline.c module so that the polling doesn't happen
unless PyOS_InputHook is not NULL.

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