On Thursday 15 September 2005 00:49, Chaitanya Krishna A wrote:
Hi,
This could be a bit off the list, but still ...
The output of uname -a of my machine is as below Linux achala 2.6.11.4-21.8-smp #1 SMP Tue Jul 19 12:42:37 UTC 2005 i686 i686 i386 GNU/Linux, and I guess SMP stands for Shared Memory Processor. I have a two processors on my mother board.
I am doing my work in Molecular Dynamics simulations. So most of the time I would be doing a lot of number crunching. Now if start a job on my machine, does it automatically run using both the processors on my machine, or will I have to use a message passing library like MPI to use both the processors?
I experimented with this some time back, I ran the same job with ./executable and also mpirun -n 2 ./executable on my machine (no clustering or anything). The second one gave maginally better results and top showed two processes running. Can someone explain what's happening?
Regards, Chaitanya.
Hi Chaitanya, I had a chat with my friend re parallel processing. He said that it is generally quite complex to modify your code to make proper use of multiple processors. There are special techniques to setting up a structure to the code so that MPI processing can manage the separation of the work. This can be done in any language, but my friend uses FORTRAN which has had separation over multiple cpus built into the language for some time now. So, I am sorry but I am not much help. Are you using FORTRAN? Regards, Colin