[ On Fri, December 18, 1998 at 09:48:10 (+1100), Robert Elz wrote: ]
> Subject: Re: le0: overflow 
>
> No, it wouldn't.   Please let me say this once again.   A lance "overflow"
> error occurs entirely within one packet.   It makes not the slightest bit of
> difference how many other packets are being sent or received or when.  A
> single packet, with none for hours before, or after, it could trigger
> exactly the same event.

Sorry, but you're message appeared on my machine only after I'd made the
blunder you clear up!  ;-)

.... and of course I didn't UTSL   :-(

But then I thought I knew the answer since I'm sitting in front of a
very similar machine with the only apparent difference being that my NFS
server is only a wimpy SS-2.

> What does make a difference is how much contention there is on the memory
> bus - which cannot be other packets (the lance can only receive or transmit
> a single packet at a time), but could be (but apparently isn't in this
> particular case) other devices competing for DMA cycles, or it could just
> be the CPU competing for memory - doing a lot of X screen updates (drawing
> into video memory) could do it, as could just regular program accesses to
> ram, if they're missing the cache.

I'm guessing that this problem is more prevalent on SS-1s with colour
frame buffers that require more CPU effort to do their thing....

-- 
							Greg A. Woods

+1 416 218-0098      VE3TCP      <gwoods@acm.org>      <robohack!woods>
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