Re: SMP/cc Cluster description

Larry McVoy
2001-12-06T23:27:10Z

On Thu, Dec 06, 2001 at 03:08:47PM -0800, David S. Miller wrote:
> From: Benjamin LaHaise <bcrl@redhat.com>
> Date: Thu, 6 Dec 2001 17:27:08 -0500
>
> - lower overhead for SMP systems. We can use UP kernels local
> to each CPU. Should make kernel compiles faster. ;-)
>
> Actually, this isn't what is being proposed. Something like
> "4 cpu" SMP kernels.

I personally want to cluster small SMP OS images because I don't want to
do the process migration crap anywhere except at exec time, it simplifies
a lot. So I need a second order load balancing term that I can get
from 2 or 4 way smp nodes. If you are willing to process migration to
handle load imbalances, then you could do uniprocessor only. I think
the complexity tradeoff is in favor of the small SMP OS clusters, we
already have them. Process migration is a rats nest.

> At the very least it is well worth investigating. Bootstrapping the
> ccCluster work shouldn't take more than a week or so, which will let
> us attach some hard numbers to the kind of impact it has on purely
> cpu local tasks.
>
> I think it is worth considering too, but I don't know if a week
> estimate is sane or not :-)

Yeah, it's possible that you could get something booting in a week but I
think it's a bit harder than that too. One idea that was kicked around
was to use Jeff's UML work and "boot" multiple UML's on top of a virtual
SMP. You get things to work there and then do a "port" to real hardware.
Kind of a cool idea if you ask me.
--
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Larry McVoy lm at bitmover.com http://www.bitmover.com/lm