Grabbed the Linpack source and compiled against /opt/openmpi/1.4.2 … using the Make.Linux_PII_CBLAS makefile. Had to grab the atlas libraries from another host. We changed $HOME and pointed to libmpi.so ($MPdir and $MPlib) and repointed $LAdir. Then it compiled fine.

More about Linpack on wikipedia

So based on what we did with the Dell burn in, follow this previous Linpack Runs link, some calculations:

• N calculation: 32 nodes, 12 gb each is 384 gb total which yields 48 gb double precision (8 byte) elements … 48 gb is 48*1024*1024*1024 = 51,539,607,552 … take the square root of that and round 227,032 … 80% of that is 181,600
• NB: start with 64, then 128, try 192 …
• PxQ: perfect square of 16×16=256, the number of cores we have.

Next create the machines files that list the hostname for each core.

for i in `seq 1 32`
do
for j in `seq 1 8`
do
echo n${i}-ib0 >> machines
done
done

Note that we're running via the hostname-ib0 port, that is the infiniband port. Probably does not matter but that way we'll stay off the provisioning switch and should see the Voltaire switch light up.

Simple script for invocation.

#!/bin/bash

export PATH=/opt/openmpi/1.4.2/bin:$PATH

export LD_LIBRARY_PATH=/opt/openmpi/1.42./lib:/home/hptest/test/lib64/atlas_GenuineIntel_x86_64

mpirun -n 256 --hostfile machines ./xhpl > hpl.log 2>&1 &

And about the best results (1.5 teraflops) we found, was with

• N = 191,600
• NB of 128
• PxQ = 16 x 16

T/V                N    NB     P     Q               Time             Gflops
----------------------------------------------------------------------------
WR00R2C4      181600   128    16    16            2642.49          1.511e+03
----------------------------------------------------------------------------
||Ax-b||_oo / ( eps * ||A||_1  * N        ) =        0.0241238 ...... PASSED
||Ax-b||_oo / ( eps * ||A||_1  * ||x||_1  ) =        0.0097160 ...... PASSED
||Ax-b||_oo / ( eps * ||A||_oo * ||x||_oo ) =        0.0016592 ...... PASSED
============================================================================
T/V                N    NB     P     Q               Time             Gflops
----------------------------------------------------------------------------
WR00R2R2      181600   128    16    16            2649.93          1.507e+03
----------------------------------------------------------------------------
||Ax-b||_oo / ( eps * ||A||_1  * N        ) =        0.0246131 ...... PASSED
||Ax-b||_oo / ( eps * ||A||_1  * ||x||_1  ) =        0.0099131 ...... PASSED
||Ax-b||_oo / ( eps * ||A||_oo * ||x||_oo ) =        0.0016929 ...... PASSED
============================================================================
T/V                N    NB     P     Q               Time             Gflops
----------------------------------------------------------------------------
WR00R2R4      181600   128    16    16            2644.63          1.510e+03
----------------------------------------------------------------------------
||Ax-b||_oo / ( eps * ||A||_1  * N        ) =        0.0231181 ...... PASSED
||Ax-b||_oo / ( eps * ||A||_1  * ||x||_1  ) =        0.0093110 ...... PASSED
||Ax-b||_oo / ( eps * ||A||_oo * ||x||_oo ) =        0.0015901 ...... PASSED
============================================================================

Looks like so.

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And that revealed a host with 10 gb memory instead of 12gb.

[root@greentail Linux_PII_CBLAS]# pdsh grep MemTotal /proc/meminfo 
n10: MemTotal:     12290464 kB
n26: MemTotal:     12290464 kB
n13: MemTotal:     12290464 kB
n3: MemTotal:     12290464 kB
n2: MemTotal:     12290464 kB
n9: MemTotal:     12290464 kB
n23: MemTotal:     12290464 kB
n30: MemTotal:     12290464 kB
n28: MemTotal:     12290464 kB
n1: MemTotal:     12290464 kB
n31: MemTotal:     12290464 kB
n20: MemTotal:     12290464 kB
n27: MemTotal:     12290464 kB
n25: MemTotal:     12290464 kB
n15: MemTotal:     12290464 kB
n16: MemTotal:     12290464 kB
n18: MemTotal:     12290464 kB
n29: MemTotal:     12290464 kB
n6: MemTotal:     12290464 kB
n7: MemTotal:     12290464 kB
n5: MemTotal:     12290464 kB
n24: MemTotal:     12290464 kB
n32: MemTotal:     12290464 kB
n19: MemTotal:     12290464 kB
n12: MemTotal:     12290464 kB
n22: MemTotal:     12290464 kB
n8: MemTotal:     12290464 kB
n11: MemTotal:     12290464 kB
n4: MemTotal:     12290464 kB
n14: MemTotal:     12290464 kB
n17: MemTotal:     12290464 kB
n21: MemTotal:     10221992 kB  <--- hmm

Since the cluster will be shut down December 28th we have an opportunity to run Linpack on the Dell cluster.

• ETHERNET
• N calculation: 20 nodes, 4/8/16 gb mix for a total of 192 gb which yields 24 gb double precision (8 byte) elements … 24 gb is 40*1024*1024*1024 = 25,769,803,776 … take the square root of that and round 160529 … 80% of that is 128423
• NB: start with 64, then 128, try 192 …
• PxQ: perfect square of 10×16=160, the number of cores we have

Since the cluster will be shut down December 28th we have an opportunity to run Linpack on the sharptail cluster.

• N calculation: 46 nodes, 24 gb per node for a total of 1,104 gb which yields 138 gb double precision (8 byte) elements … 138 gb is 138*1024*1024*1024 = 148,176,371,712 … take the square root of that and round 384936 … 80% of that is 307,950
• NB: start with 64, then 128, try 192 …
• PxQ: perfect square of 9×10=92, close to the number of cores we have.

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