At 10:35 PM -0400 7/10/00, Allen Briggs wrote:

>  > Anyone using a 100 baseT card in a 68k Mac with NetBSD? Can the rest of
>>  the hardware handle it or is there no improvement in speed? Believe it or
>>  not, I run a proxy (squid) on a NetBSD box (up for 271 days and
>>  counting) that is on a Q700. I would like to speed it up a little bit if
>>  the NIC would help.
>
>Speeding up the NIC would almost certainly help for throughput.  The
>disks are not that fast, but if you're running data cached in memory
>or from NIC to NIC, the Q700 and friends should be able to more than max
>out a 10Mbit NIC (they probably can't come too close to maxing out a
>100Mbit NIC, though, as I think the nubus and memory bandwidth limits
>will be reached before the NIC limitations [I don't have the docs in
>front of me, but ISTR that the nubus maxes out at 10MB/s]).
>
>There aren't any 100Mbit NICs supported at the moment, though someone
>has recently spoken up that there are some available for developers
>to work on, and I'm interested in seeing it happen...
>
>-allen

AFAIK, the theoretical max transfer on NuBus is 40MB/sec.  In testing 
raw RAM throughput with Newer's RAMometer v1.3.4, the best I've seen 
on my Quadra class machines is 6.3MB/sec with interleaved memory on a 
Quadra 650, so I imagine that would be a limiting factor on any RAM 
to NuBus communication.

I'm not sure what other limitations there are, but in my ethernet 
testing with NuBus and onboard ethernet in my 68k Macs running 
NetBSD, the best I've seen them do is 380k/sec.  This is on a 
switched local network I have set up.  My HP Vectra (Pentium 180) 
running Sun Solaris 2.7 x86 can get around 930k/sec across the same 
network.  Obviously there are a lot of architecture differences here 
(just about everything is different), but I can at least say that its 
not the network limiting the Mac 68k NetBSD machines to 380k/sec.

And if I remember correctly, the 10/100 Nubus cards offered at most a 
2x, not a 10x increase in throughput.  Will that translate to 
720k/sec?  I don't know.  I don't know where the bottlenecks are, and 
I forget what the max throughput on the 10/100 NuBus cards were.	I 
can't find any info about Farallon's 10/100 NuBus card (PN990a-TX) on 
their site, but they do still carry and stock it, at least at their 
online store (for $193.99!!)

--
Nathan Raymond



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