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From: Allan Menezes (amenezes007_at_[hidden])
Date: 2006-08-16 22:55:27

Hi AnyOne,
      I have an 18 node cluster of heterogenous machines. I used fc5 smp
kernel and ocsar 5.0 beta.
I tried the following out on a machine with Open mpi 1.1 and 1.1.1b4
versions. The machine consists of a Dlink 1gigb/s DGE-530T etherent card
2.66GHz dual core Intel Cpu Pentium D 805 with Dual Cannel 1 gig DDR
3200 ram. I compiled the ATLAS libs (ver 3.7.13beta) for this machine
and HPL (xhpl executable) and ran the following experiment twice:
content of my "hosts" file1 for this machine for 1st experiment: slots=2
content of my "hosts" file2 for this machine for 2nd experiment:

On the single node I ran for HPL.dat N =6840 and NB=120 : 1024 MB of Ram
N = sqrt(0.75* ((1024-32 video overhead)/2 )*1000000*1/8)=approx 6840;
512MB Ram per CPU otherwise the OS uses the hard drive for virtaul
memory. This way it resides totally in Ram.
I ran this command twice for the two different hosts files above in two
# mpirun --prefix /opt/openmpi114 --hostsfile hosts -mca btl tcp, self
-np 1 ./xhpl
In both cases the performance remains the same around 4.040 GFlops I
would expect since I am running slots =2 as two CPU's I would get a
performance increase from expt 2 by 100 -50%
But I see no difference.Can anybody tell me why this is so?
I have not tried mpich 2.
Thank you,
Allan Menezes