Re: linux-kernel-digest V1 #2914

Paul Barton-Davis (pbd@Op.Net)
Mon, 30 Nov 1998 21:32:51 -0500

Stephen C. Tweedie writes:

( on using 1024 cpus)

>Binding that many CPUs together is hard! You tell me how you plan to do
>it, and _then_ I'll tell you whether clustering is faster. :)

I'd do it the same way that KSR did, except that I'd use off the shelf
processors. Cornell, I think, had a 1024 node KSR-1 and maybe even a
1024 KSR-2. They never did get all the kinks out of their cache
coherency protocol, but I think that between them and Alewife, it
could probably be done.

Next question, however: why ? Problems that benefit from this level of
parallelism using general purpose microprocessors (as distinct from
the PDP-neural-network kinds of parallelism) are typically well served
by clustering.

This "why" question, along with the fact that UP speeds keep making
various MP configurations redundant a couple of years after their
owners spent big money on them, have been the bugbear of most
large-scale MP designs.

--p (still angry that UWashington could spend $1M on a KSR and then
throw it away a year later)

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