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SubjectRe: [PATCH] Binding processes to selected CPUs
On Wed, Oct 13, 1999 at 04:40:55AM -0400, avik@altavista.net wrote:
...
> I redid my tests, this time against physical memory,
> and they show that there is no performance gain with
> 128kB caches. Perhaps machines with more cpus and
> larger caches will benefit, but the smaller ones will
> not.

People here seem to presume that all the world SMPs are UMA systems.

Taxonomy of parallel computers (by David Black, back then at CMU):
- UMA Uniform Memory Access (your usual tightly coupled SMP)
- NUMA Non-Uniform Memory Access (processors have good access
to memory which is local to them, but slower access to
memory at other CPU/MEM boards; beasts like SUN E 10000)
- NORMA NO Remote Memory Access (your average Beowulf)
Spice this with Cache Coherence, and you get CC-NUMA (and CC-UMA).

(That was after "In Search of Clusters" by Gregory F. Pfister)

Your observations may well hold at UMA systems.

Binding facilities make a *lot* sense at NUMA systems.
(Also memory allocation policies must be tuned accordingly; allocing
process local memory from remote board hurts process, AND system
performance when processor most go thru system memory crossbar to
access that memory causing contention for that resource..)

/Matti Aarnio <matti.aarnio@sonera.fi>

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