Path: utzoo!utgpu!news-server.csri.toronto.edu!rutgers!apple!ames!sgi!vjs@rhyolite.wpd.sgi.com
From: vjs@rhyolite.wpd.sgi.com (Vernon Schryver)
Newsgroups: comp.sys.sgi
Subject: Re: Inter-Process communication: Help!
Summary: turn of TCP_NODELAY
Keywords: TCP vs UDP
Message-ID: <79492@sgi.sgi.com>
Date: 1 Jan 91 02:47:35 GMT
References: <1990Dec31.090634.20329@cs.UAlberta.CA>
Sender: guest@sgi.sgi.com
Distribution: comp.sys.sgi
Organization: Silicon Graphics, Inc., Mountain View, CA
Lines: 17

In article <1990Dec31.090634.20329@cs.UAlberta.CA>, cdshaw@cs.UAlberta.CA (Chris Shaw) writes
> ...
> So anyway, is there any way around this with TCP? What's going on? Is there
> an assumption of send-receive-reply within TCP that cannot be beaten?
> Is UDP the only way? Can anyone recommend a good book on the subject?

Yes, there is an important speed hack called, I think, "the Nagle
algorithm" in 4.3BSD derived TCP implementations.  I think the Host
Requirements RFC requires it.  It can be turned off.  If possible, it would
be better to change your application to use more "balanced" exchanges.

Check tcp(7p) and getsockopt(2) for TCP_NODELAY.  Those man pages are in
IRIX 3.3 on 4D's.  I don't remember man pages what we shipped in 3.6 for
the 3000, and I don't know how well the ioctl worked in those ancient days.


Vernon Schryver,   vjs@sgi.com