[Beowulf] Re: RRDtools graphs of temp from IPMI
d.love at liverpool.ac.uk
Tue Nov 11 06:51:46 PST 2008
Prentice Bisbal <prentice at ias.edu> writes:
> The advantage of using IPMI is that it is hardware based, so there
> shouldn't be any OS noise to slow down the MPI calculations.
Yes iff you do it out-of-band, which is probably less convenient, and is
significantly slower on our systems, at least. Actually, is it clear
that interacting with the firmware generally won't cause any jitter? I
could imagine it might.
Our vendor installed a daemon doing in-band IPMI sensor probes which I
didn't initially know about, since it wasn't sending the ganglia metrics
correctly anyhow. I don't know whether that means they disagree with
the effect on MPI performance or what.
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