Re: [PATCH] top level scheduler domain for ia64

From: Matthew Wilcox <>
Date: 2004-11-02 04:16:49
On Mon, Nov 01, 2004 at 09:07:32AM -0800, Jesse Barnes wrote:
> If I understand you right, you don't want a top level domain for your 32 way 
> systems, but you *do* want the node domains to span the whole thing.  Is that 
> right?
> If so, you could do something like this I think?
>  if (numnodes <= SMALL_SYSTEM_THRESHOLD) {
>   SD_NODES_PER_DOMAIN = numnodes;
>   build_node_domains(); /* each one spans the system */
>  } else {
>   SD_NODES_PER_DOMAIN = 4; /* or whatever */
>   build_node_domains(); /* only spans nearby nodes */
>   build_top_level_domain(); /* whole system, infrequently balanced */
>  }
> Would that address your concerns?

Doesn't sound like a great idea.  HP's already shipping 128-way Superdome
IA-64 systems, and they'll want to be set up rather differently from the
Altix systems.  I think this code needs to be autotuning so it doesn't
need to be touched whenever a vendor releases a new configuration (I
think I heard that NASA's Altixes had a custom CPU brick with twice the
CPUs in it?)

"Next the statesmen will invent cheap lies, putting the blame upon 
the nation that is attacked, and every man will be glad of those
conscience-soothing falsities, and will diligently study them, and refuse
to examine any refutations of them; and thus he will by and by convince 
himself that the war is just, and will thank God for the better sleep 
he enjoys after this process of grotesque self-deception." -- Mark Twain
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Received on Mon Nov 1 12:27:33 2004

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