PC GAMESS-related discussion club

Alex Granovsky
gran@classic.chem.msu.su

your system has four processor cores. Moreover, as your processors support HTT, and it seems it is enabled, you have eight logical cores available. However, this does not mean that running eight PC GAMESS processes in parallel would be a good idea.

For discussion of some HTT-related topics, look at:

http://classic.chem.msu.su/gran/gamess/smp.html

In brief, I would recommend you to use only four logical processors for calculations, and thus the following procgrp file:

local 3

In this case, PC GAMESS will bind most of its computation threads to the specific logical instances of the HTT-enabled cores for better efficiency, and will decide dynamically whether to use other logical cores during its execution, or not at all.

For the alternative options, please see the link above.


Another point is that the WMPI 1.3 distribution is outdated and buggy. The recommended MPI implementation for Windows PC GAMESS version is NT-MPICH or NT-MPICH-SMP. There are already several recent threads on this forum discussing how to run PC GAMESS in parallel using these MPI implementations.


Best regards,
Alex Granovsky




On Fri Mar 28 '08, Randy Miles wrote
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>I am unable to utilize the full processing capacity of this
>computer. It has 2 physical cpus on one board with shared memory.
>Each physical cpu has 4 logical processors. I am using
>mpibind.wmpi-1.3.dll, and the following procgrp file:

>local 0
>localhost 1 C:\PCGAMESS\PG2\pcgamess.exe
>localhost 1 C:\PCGAMESS\PG3\pcgamess.exe
>localhost 1 C:\PCGAMESS\PG4\pcgamess.exe
>localhost 1 C:\PCGAMESS\PG5\pcgamess.exe
>localhost 1 C:\PCGAMESS\PG6\pcgamess.exe
>localhost 1 C:\PCGAMESS\PG7\pcgamess.exe
>localhost 1 C:\PCGAMESS\PG8\pcgamess.exe

>In this case, two pcgamess instances are initiated, but they both
>hand indefinitely, producing no output. If I try the following
>procgrp file

>local 7

>I get 8 pcgamess instances initiated and valid output, but they are
>confined to 4 of the 8 processors, utilizing only half of my
>resources.

>I recognize that for efficiency I should place each of the working
>directories on separate disks, and I plan to do that in the future.

>Is there something else I should be doing differently?

>Thanks-
>