[Beowulf] The Walmart Compute Node?

[David Mathog]

Eugen Leitl <eugen at leitl.org> wrote:
> It's actually a VIA C7-D. Way worse than a Celery in absolute performance,
> but might be okayish to stellar in terms of Ops/Joule.

To expand on the stellar part slightly, if the proposed cluster
is to be powered on all the time, but won't be in use all the
time, it's worth noting that the C7 has very low power modes
which are still running, albeit very slowly.  This would make such a
cluster quite responsive in terms of starting jobs from the "just
sitting around" state, without requiring any of the complications,
overhead, and longish delays associated with returning from
sleep modes.  In theory the kernel should handle this power conservation
for you automatically if the cpufreq modules are 
installed and configured properly.  The power consumption when
the system is sitting around would be minimal, probably just a few watts.

This assumes that the board in question actually supports these low
power modes.  This is probably NOT a safe assumption for an el cheopo
board.

Regards,

David Mathog
mathog at caltech.edu
Manager, Sequence Analysis Facility, Biology Division, Caltech