[Beowulf] Re: Performance degrading

Jörg Saßmannshausen jorg.sassmannshausen at strath.ac.uk
Tue Dec 22 05:30:54 EST 2009


Hi all,

right, following the various suggestion and the idea about oversubscribing the 
node, I have started the same calculation again on 3 nodes but this time only 
with 3 processes on the node (started), so that will leave room for the 4th 
process which I believe will be started by NWChem.
Has anything changed? No.

top - 10:24:06 up 21 days, 17:29,  1 user,  load average: 0.25, 0.26, 0.26
Tasks: 131 total,   1 running, 130 sleeping,   0 stopped,   0 zombie
Cpu0  :  4.3% us,  1.0% sy,  0.0% ni, 93.7% id,  0.0% wa,  0.0% hi,  1.0% si
Cpu1  :  2.7% us,  0.0% sy,  0.0% ni, 97.3% id,  0.0% wa,  0.0% hi,  0.0% si
Cpu2  :  0.7% us,  0.0% sy,  0.0% ni, 99.3% id,  0.0% wa,  0.0% hi,  0.0% si
Cpu3  :  0.0% us,  0.0% sy,  0.0% ni, 99.0% id,  1.0% wa,  0.0% hi,  0.0% si
Mem:  12308356k total,  5251744k used,  7056612k free,   377052k buffers
Swap: 24619604k total,        0k used, 24619604k free,  3647568k cached

  PID USER      PR  NI  VIRT  RES  SHR S %CPU %MEM    TIME+  COMMAND
29017 sassy     15   0 3921m 1.7g 1.4g S    3 14.8 384:50.34 nwchem
29019 sassy     15   0 3920m 1.8g 1.5g S    2 15.4 379:26.55 nwchem
29018 sassy     15   0 3920m 1.8g 1.5g S    1 15.5 380:31.15 nwchem
29021 sassy     15   0 2943m 1.7g 1.7g S    1 14.9  42:33.81 nwchem   <- 
process started by NWChem I suppose

As Reuti pointed out to me, NWChem is using Global Arrays internally and only 
MPI for communication. I don't think the problem is the OpenMPI I have. I 
could upgrade to the latest, but that means I have to re-link all the 
programs I am using.

Could the problem be the GA?

All the best

Jörg


-- 
*************************************************************
Jörg Saßmannshausen
Research Fellow
University of Strathclyde
Department of Pure and Applied Chemistry
295 Cathedral St.
Glasgow
G1 1XL

email: jorg.sassmannshausen at strath.ac.uk
web: http://sassy.formativ.net

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