[Beowulf] newbie's dilemma
hahn at physics.mcmaster.ca
Thu Mar 2 13:01:38 PST 2006
> Note also that I'm guessing that these boxes draw somewhere between 200
> and 300 watts fully loaded with tasks (anybody out there measure?
I recently did some measurements on new nodes: HP DL145G2's with 8GB ram,
2x80G disks, quadrics elan4 cards:
2x DC opt/2.2 2x SC opt/2.6
booting 259-317 244-313
idle 265 255
1p thrash -g6 286 275
1p stream 291 284
2p 290-301 310
"idle" means nothing explicitly running (though the distro includes a
surprising number of irrelevant daemons.) "thrash -g 6" is a program that
allocates 6GB and just repeatedly memset's it. it's single-threaded,
but since 6GB is large enough to require both CPU's banks of memory, the
other cpu is not inactive. 1/2/3 are an openmp version of stream, run
with "numactl -l".
firing up streaming IO during one of these runs didn't really change
the power picture at all. then again, disks are not more than ~15W
when spun up, so this is not a big surprise.
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