[Python-Dev] socket.c, _rbufsize

Kristján Valur Jónsson kristjan at ccpgames.com
Thu Nov 27 15:50:07 CET 2008

I came across this in socket.c:
        # _rbufsize is the suggested recv buffer size.  It is *strictly*
        # obeyed within readline() for recv calls.  If it is larger than
        # default_bufsize it will be used for recv calls within read().

What I worry about is the readline() case.  Is there a reason why we want to strictly obey it for that function?  Note that in the documentation for _fileobject.read() it says:
        # Use max, disallow tiny reads in a loop as they are very inefficient.

The same argument surely applies for readline().

The reason I am fretting about this is that httplib.py (and therefore xmlrpclib.py) specify bufsize=0 when createing their socket fileobjects, presumably to make sure that write() operations are not buffered but flushed immediately.  But this has the side effect of setting the _rbufsize to 1, and so readline() calls become very slow.

I suggest that readline() be made to use at least defaultbufsize, like read().  Any thoughts?



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