[MPICH] how to pin a processes to CPU/core with mpiexec ?

[chong tan]

some background:
the box is a SUN ultra40, 2 opteron 280, 4 core total.
 The box used to run SOlaris 10, I 'upgraded' it to
Redhat RS 4 U2 few days ago.
The test application runs 3 processes using mpiexec,
th emaster is the light-weight sync and dispatcher.  2
slaves run identical processes with identical data set
in identical order.

In Solaris, both slaves run with about the same CPU%. 
In Linux, one Slave is getting 25% less CPU%.  So, in
SOlaris, the job finished 30% faster than the same job
under Linux.

There were no other application running when the test
application ws run, so the siituation is not so good.

My thinking is that maybe, just maybe, 1 slave process
was unfortunate that it got kicked around the core. 
If I can pin it down to a specic core, then it shall
get more cpu%.


any suggestion ?

thanks
tan



__________________________________________________
Do You Yahoo!?
Tired of spam?  Yahoo! Mail has the best spam protection around 
http://mail.yahoo.com