[Beowulf] ECC exerciser/exorciser?

Carlos Fernandez Sanchez carlosf at cesga.es
Tue Jan 27 02:06:40 PST 2009

Well, actually is an HP RX7640

We don´t use node memory availability to balance job placement right now. We
are studying the influence of thread/core/memory placement on the
performance of different codes and the results are quite interesting
(depending on the type of test, it´s more efficient to put the threads on
the same "node" or in separates "nodes". In some cases the default kernel
placement of threads in the system can be improved). We plan to implement
this mechanism with cpusets (or maybe with taskset)

Carlos Fernandez Sanchez, PhD
Systems Manager
Centro de Supercomputacion de Galicia (CESGA)
Avda. de Vigo s/n. Campus Sur
15705 Santiago de Compostela
Tel.: (+34) 981569810, ext. 232
P Before printing, think about ENVIRONMENTAL responsibility!

-----Mensaje original-----
De: Mark Hahn [mailto:hahn at mcmaster.ca] 
Enviado el: lunes, 26 de enero de 2009 17:02
Para: Carlos Fernandez Sanchez
CC: 'Beowulf Mailing List'
Asunto: RE: [Beowulf] ECC exerciser/exorciser?

> Regarding numactl, we are using it and shows good results:
> numactl --hardware
> available: 3 nodes (0-2)
> node 0 size: 57280 MB
> node 0 free: 32579 MB
> node 1 size: 57255 MB
> node 1 free: 55920 MB
> node 2 size: 16371 MB
> node 2 free: 16140 MB
> (on a 128GB system, SLES10SP1)

sounds like an altix.  yes, it works fine on our 64 node altix as well.
what I'm wondering is how widespread it is to find commodity PCs that 
have inconsistent numactl output.

incidentally, do you use node memory availability 
to balance job/thread placement?

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