Path: utzoo!attcan!utgpu!jarvis.csri.toronto.edu!mailrus!cwjcc!neoucom!wtm
From: wtm@neoucom.UUCP (Bill Mayhew)
Newsgroups: comp.dcom.modems
Subject: Re: TB+ Performance [Was: Trouble with TB Plus (Please Help!!)]
Keywords: TB+, UUCP
Message-ID: <1724@neoucom.UUCP>
Date: 20 Sep 89 10:58:28 GMT
References: <124@clleth.UUCP> <470@gufalet.UUCP> <3635@daisy.UUCP>
Organization: Northeastern Ohio Universities College of Medicine
Lines: 30


We had a lot of problems with getting decent performance from our
trailblazers when we were running on our bsd 4.2 vax.  The context
switching combined with the brain-damaged DZ serial interface
really hammered on performance.

We draged our AT&T Unixpc out of the closet and set it up as our
domain entry point, and allow it to do nothing other than process
uucp traffic.  We've had pretty good luck with the unixpc/TB+
combination.  We talk to scooter, which is in CA, while we are here
in lovely Rootstown, OH and get about 900-1200 char/sec transfer
rates on big news batches.  Our local connections with impulse,
aablue, etc. usually are around 1000-1200 char/sec.  The xferstats
reported by uucp are not really reflective of your real rate unless
you are considering a 40-50K file.

The quality of the serial port drivers and the design of the UARTS
and SILO hardware make a big difference.  Also, the way interrupts
are handled in bsd extracts a penalty.  I really don't know what
goes on with the System V-ish kernel on the Unixpc, as that is sold
as a black box; it seems to handle serial I/O pretty well, though.

As far as micropackets on the the TB+ go, it doesn't seem to have
any effect unless both ends have micropackets enabled.  I tried
enabling micropackets on my end and didn't see any difference in
performance.  My guess is that scooter does not have micropackets
enabled.


Bill