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From: pilger@uhunix1.uhcc.Hawaii.Edu (Eric Pilger)
Newsgroups: comp.protocols.nfs
Subject: Re: Sun PC-NFS TCP behaviour
Message-ID: <9234@uhccux.uhcc.Hawaii.Edu>
Date: 6 Sep 90 19:45:17 GMT
References: <956@massey.ac.nz>
Sender: news@uhccux.uhcc.Hawaii.Edu
Organization: University of Hawaii
Lines: 18

I don't know if this has a bearing on the overhead you are
experiencing with PC-NFS Telnet.  I have been using the Programmer's
Toolkit and found that there is a LOT of overhead on socket writes.
By sending a large amount of data in varying size pieces and measuring
the throughput for each instance, I came to the conclusion that there
is as much as a 1/5 of a second overhead for each write.  This value
is probably not extremely accurate, but it is in the right ballpark.

Sending data 64K at a time, my throughput was 100-300K per second.
Sending data 512 bytes at a time, throughput was down to 5-10K per
second.  First, you can well imagine what this does to telnet.
Everytime you press a key, a write has to occur, and you incur a 1/5
of a second overhead.  Second, why does this happen?  Is it the fault
of the socket drivers?  Is it the fault of the ethernet card?
Inquiring minds would like to know (and fix.)

				Eric Pilger
				NASA Infrared Telescope Facility