Re: Whining about NUMA. :) [Was whining about 2.5...]

Martin J. Bligh (Martin.Bligh@us.ibm.com)
Mon, 08 Oct 2001 12:20:59 -0700


>> That's what I was planning on ... we'd need m x n classzones, where m
>> was the number of levels, and n the number of nodes. Each search would
>> obviously be through m classzones. I'll go poke at the current code some more.
>
> You say "numbers of levels" as in each level being a given number of nodes
> on that "level" distance ?

Yes.

For example, if the only different access speeds you have were "on the local
node" vs "on another node", and access times to all *other* nodes were the
same, you'd have 2 levels.

If you have "on the local node" (10 ns) vs "on any node 1 hop away" (100ns),
"on any node 2 hops away" (110ns), that'd be 3 levels. (latency numbers picked
out of my portable random number generator ;-) ).

If the latencies on a 4 level system turn out to be 10,100,101,102 then it's only
going to be worth defining 2 levels. If they turn out to be 10,100,1000, 10000,
then it'll (probably) be worth doing 4 ....

M.

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