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Date:      Tue, 28 Oct 1997 07:33:52 -0500 (EST)
From:      Alfred Perlstein <perlsta@cs.sunyit.edu>
To:        Thomas David Rivers <rivers@dignus.com>
Cc:        freebsd-hackers@freefall.FreeBSD.org
Subject:   Re: sio silo overflows on a P75 @ 38400 baud?
Message-ID:  <Pine.BSF.3.96.971028072955.2814D-100000@server.local.sunyit.edu>
In-Reply-To: <199710281110.GAA06120@lakes.dignus.com>

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if you've only seen three a day or so, it makes total sense that they
might be occuring during the nightly/weekly/monthly scripts that seriously
thrash your system.

again it's easy to has 3 (or more) situtations, in your situation (not a
lot of resources) where the system get's overloaded just for a few seconds
or less causing the overflow...

it's not more irritating, it's unavoidable. :)
just think how many interupts there might be in second occuring on your
serial port, just a little overactivity on the disk..... and wha-la.

> > you are quite possbily over loading your system with a combination of
> > writes and swapping (8megs of ram? ewwww)
> 
>  Hmm... good point.
> 
> > 
> > if disk activity is constant it's quite possible to reach a load of 9.0+
> > i did while doing a buildworld and making my kernel -j8... it was at like
> > 9.6+ at times... pretty cool as X kept freezing for several seconds at a
> > time...
> 
>  But - the disk activity isn't constant; it's no where near that
> (being a little twiddle about every 13 seconds). In fact, uptime
> shows my load average as
>   7:02AM  up  8:52, 2 users, load averages: 0.00, 0.00, 0.00
> 
>  So, I don't believe that's the culprit.
> 
>  In the span of this 8:52 hours, though, I've only seen 3 silo
> overflows...  So, the issue appears to be intermittent... (which
> makes it more aggravating... :-) )
> 
> 	- Dave Rivers -
> 
> > 
> > On Mon, 27 Oct 1997, Thomas David Rivers wrote:
> > 
> > > 
> > > I was just wondering - should it be possible, at 38400 baud,
> > > in multi-user mode, but nothing else really going on; to get
> > > silo overflows on a P75 with 16550 (clone?) UARTs?
> > > 
> > > I'm doing a SL/IP connection and sending the output of
> > > dd'ing a tape back to the P75 system for un-tarring.  The
> > > sending system is a P200 (running FreeBSD 2.2-970510.)
> > > 
> > > I'm getting these silo overflows with 2.2.5.
> > > 
> > > I'm hoping someone can whip out some figures on the
> > > interrupt latency to suggest that a P75 should be able
> > > to deal with receiving 38400...
> > > 
> > > This could, of course, be an artifact of some device
> > > holding the bus too long.  The P75 machine is a laptop
> > > with a IDE drive (to which I'm writting) and 8 meg of memory;
> > > again, running 2.2.5-RELEASE.
> > > 
> > > 	 - Thanks -
> > > 	- Dave Rivers -
> > > 
> > 
> > 
> 




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