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From: root@deadline.snafu.de (Andreas S. Wetzel)
Subject: Re: tty-level buffer overflows - what to do?
To: jgreco@brasil.moneng.mei.com (Joe Greco)
Date: Thu, 4 Apr 1996 19:34:40 +0200 (MET DST)
Cc: current@freebsd.org
In-Reply-To: <199604041724.LAA01512@brasil.moneng.mei.com> from Joe Greco at "Apr 4, 96 11:24:02 am"
Organization: A world stranger than you have ever imagined.
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Hi!
---

Joe Greco writes:

] > On a relatively fresh installed -current Box which serves as a modem
] > server for two V34+ modems and one V34 Modem on our local LAN, I get
] > lots of messages on the sysconsole when doing high-speed transfers:
] > 
] > sio2: 1988 more tty-level buffer overflows (total 23215)
] > etc...
] > 
] > This especially happens when transferring pure ASCII data which gets
] > quite good compressed by the two modems so that I actually transfer
] > at bitrates of about 50kbit and higher.
] > 
] > Can I do anything about that (i.e. increase memory on this machine) or is
] > this a problem related to the sio driver?
] > 
] > Thankful for any advice
] 
] What are you doing?  rz/sz?  What kind of machine is it?  (a 386sx/16 has
] much less CPU than a P90..)  Are you using hardware flow control correctly?
] What kind of drives?  IDE drives bite, particularly if they are being used
] at the same time as the serial port... etc, etc.
] 
] "More data, please!"  :-)

The machine is a 486SX at 40 MHz with 4 Meg. RAM and a 210 Mb IDE hard drive.
The serial ports used on the modems are all of type 16550A. RTS/CTS flow
control is hardwired for all modem lines. The machine has one dedicated
slip line as well as two dialup ports attached to it. The syslog messages
all seemed to related to the first dialup port which is a V34+ modem operated
at 115k2 bps. The mgetty on the dialup ports is configured to do a direct
rlogin onto another FreeBSD machine for all logins, so it just hands off
the dialup connections.

Regards, mickey

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