Messages in this thread | | | Date | Wed, 13 Oct 1999 12:17:34 +0300 | From | Matti Aarnio <> | Subject | Re: [PATCH] Binding processes to selected CPUs |
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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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