[Pw_forum] Output and parallelization problem in pw.x

2007-02-12 Thread Lawrence Lee
Dear all,

I have serveral problems about pw.x.

The performance of pw.x running in parallel under inter-node, is unreasonbly 
poor (about 25%). Later, I type sar to check, and find that something called 
"contextswitch" appears very frequently. But when pw.x is run under intra-node 
process, the problem did not occur and the performance become very good (>90%). 
 I think that "contextswitch" cause the problem. But why did it occur and how 
to fix the problem?

The second problem is about output file of pw.x. I want to get the stress 
tensor of each step of a pw.x (not cp.x) molecular dynamic run. I know that 
they exist in the standard output file. But the format is very inconvenient for 
further proccessing. Do anyone know is there any flag which can be specified to 
output a file of stress?

Thanks a lot!

Lawrence

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[Pw_forum] Output and parallelization problem in pw.x

2007-02-12 Thread Paolo Giannozzi
On Feb 12, 2007, at 10:40 , Lawrence Lee wrote:

> The performance of pw.x running in parallel under inter-node,
> is unreasonably poor (about 25%).

it is a well-known problem of Intel motherboards. See for instance:
http://www.democritos.it/pipermail/pw_forum/2006-December/005540.html

Paolo
---
Paolo Giannozzi, Democritos and University of Udine, Italy





[Pw_forum] Output and parallelization problem in pw.x

2007-02-12 Thread degironc
Lawrence Lee wrote:

> The second problem is about output file of pw.x. I want to get the
> stress tensor of each step of a pw.x (not cp.x) molecular dynamic run.
> I know that they exist in the standard output file. But the format is
> very inconvenient for further proccessing. Do anyone know is there any
> flag which can be specified to output a file of stress?
>
grep -e "P=" --after 3 pw-vc.out

hope it helps
stefano