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Date:      Tue, 8 Jun 1999 00:42:00 -0600 (MDT)
From:      "James R. Shrenk" <dionysos3@crosswinds.net>
To:        Mark Ovens <markov@globalnet.co.uk>
Cc:        Doug Jennings <dougj@netdoor.com>, freebsd-questions@FreeBSD.ORG
Subject:   Re: silo overflow errors
Message-ID:  <Pine.BSF.4.05.9906080036410.6452-100000@neptune.twrol.com>
In-Reply-To: <19990607232356.E255@marder-1>

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looks good so far.  I took a visit around some man pages and the web and
it seems unlikely that it's actually the modem that would be causing the
problem.  Check the output of top during your ppp sessions.  In
particular, what is your CPU usage during that time.  The data that's
buffered in the UART seems to be dropping in this case.  The slow is then
probably a result of packets being retransmitted to account for the
errors.  The man page for 3.2-release says that these silo overflows are
the result of a problem with the interrupt handler.  Although I'm sketchy
on this, your serial port may not be getting enough attention from the CPU
so it may be worth checking out.

James

On Mon, 7 Jun 1999, Mark Ovens wrote:

> On Mon, Jun 07, 1999 at 05:17:53PM -0500, Doug Jennings wrote:
> > When I get the output of dmesg, it contains the following lines:
> > 
> > sio0 at 0x3f8-0x3ff irq 4 flags 0x10 on isa
> > sio0: type 16550A
> > 
> > I knew it had to be a 16550A UART because the computer is brand new with all
> > the appropriate bells / whistles / et cetera.  Argh.  I suppose I will see
> > if I can slow down the modem now.
> > 
> > One more question...do you think the problem is happening inside the modem
> > itself?  Or could it be caused by some kind of interference in my serial
> > cable?
> 
> It would be worth checking the shield on your cable, especially if
> it runs parallel to the mains lead. I've seen silo overflow errors
> generated at the rate of >50 per second on a Sun with serial lines
> to terminals running through a factory close to arc welders :-)
> 
> > I am obviously grasping here, but I just can't figure out why I am
> > having silo errors with such a supposedly good modem (external courier
> > v.everything 28800).
> > 
> > >What is your dmesg output?  It looks like you might have a older UART
> > >(8250 maybe?)  If that's the case, you might try slowing the modem down to
> > >14400 and see if that doesn't help.
> > >
> > >
> > >On Mon, 7 Jun 1999, Doug Jennings wrote:
> > >
> > >>
> > >> After finally getting user ppp to work, I keep running into the
> > >> following problem.  Once I establish a ppp connection and I try to
> > >> send/receive any data whatsoever  (for example, opening a telnet
> > session), I
> > >> get the message:
> > >>
> > >> /kernel:  sio0:  1 more silo overflow (total 1)
> > >>
> > >> The 'total' goes up each time I send/receive any data (for example, if I
> > >> issue a "ls" command in the telnet session and have to receive the output
> > of
> > >> that).  It slows down my 28800 modem to an absolute crawl.
> > >>
> > >> Any ideas on a fix for this? I am running a fresh installation of FreeBSD
> > >> 3.1 and I am using an external USR v.everything courier modem.  I know
> > that
> > >> it has to do with some buffering issue -- I just don't know how to fix
> > it.
> > >>
> > >> Any ideas would be appreciated.
> > >>
> > >> Thanks,
> > >>
> > >> -Doug
> > 
> > 
> > 
> > To Unsubscribe: send mail to majordomo@FreeBSD.org
> > with "unsubscribe freebsd-questions" in the body of the message
> > 
> 
> -- 
>       FreeBSD - The Power To Serve http://www.freebsd.org
>       My Webpage http://www.users.globalnet.co.uk/~markov
> _______________________________________________________________
> Mark Ovens, CNC Apps Engineer, Radan Computational Ltd. Bath UK
> CAD/CAM solutions for Sheetmetal Working Industry
> mailto:marko@uk.radan.com                  http://www.radan.com
> 
> 
> 
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> 
> 



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