Re: [O-MPI users] LAM vs OPENMPI performance

2006-01-04 Thread Jeff Squyres
On Jan 4, 2006, at 5:05 PM, Tom Rosmond wrote: Thanks for the quick reply. I ran my tests with a hostfile with cedar.reachone.com slots=4 I clearly misunderstood the role of the 'slots' parameter, because when I removed it, OPENMPI slightly outperformed LAM, which I assume it should. Thanks f

Re: [O-MPI users] LAM vs OPENMPI performance

2006-01-04 Thread Tom Rosmond
Thanks for the quick reply. I ran my tests with a hostfile with cedar.reachone.com slots=4 I clearly misunderstood the role of the 'slots' parameter, because when I removed it, OPENMPI slightly outperformed LAM, which I assume it should. Thanks for the help. Tom Brian Barrett wrote: On Jan

Re: [O-MPI users] LAM vs OPENMPI performance

2006-01-04 Thread Patrick Geoffray
Hi Tom, users-requ...@open-mpi.org wrote: I am pretty sure that LAM exploits the fact that the virtual processors are all sharing the same memory, so communication is via memory and/or the PCI bus of the system, while my OPENMPI configuration doesn't exploit this. Is this a reasonable diagnos

Re: [O-MPI users] LAM vs OPENMPI performance

2006-01-04 Thread Brian Barrett
On Jan 4, 2006, at 4:24 PM, Tom Rosmond wrote: I have been using LAM-MPI for many years on PC/Linux systems and have been quite pleased with its performance. However, at the urging of the LAM-MPI website, I have decided to switch to OPENMPI. For much of my preliminary testing I work on a si

[O-MPI users] LAM vs OPENMPI performance

2006-01-04 Thread Tom Rosmond
Hello: I have been using LAM-MPI for many years on PC/Linux systems and have been quite pleased with its performance. However, at the urging of the LAM-MPI website, I have decided to switch to OPENMPI. For much of my preliminary testing I work on a single processor workstation (see the attache