On Tuesday, September 13, 2011 09:07:32 AM nn3003 wrote: > Hello ! > > I am running wrf model on 4x AMD 6172 which is 12 core CPU. I use OpenMPI > 1.4.3 and libgomp 4.3.4. I have binaries compiled for shared-memory and > distributed-memory (OpenMP and OpenMPI) I use following command > mpirun -np 4 --cpus-per-proc 6 --report-bindings --bysocket wrf.exe > It works ok and in top i see there are 4 wrf.exe and each has 6 threads on > cpu0-5 12-17 24-29 36-41 However, if I want to run 8 or more e.g. > mpirun -np 4 --cpus-per-proc 12 --report-bindings --bysocket wrf.exe > I get error > Your job has requested more cpus per process(rank) than there > are cpus in a socket: > Cpus/rank: 8 > #cpus/socket: 6 > > Why is that ? There are 12 cores per socket in AMD 6172.
In reality a 12 core Magnycours is two 6 core dies on a socket. I'm guessing that the topology code sees your 4x 12 core as a 8x 6 core. /Peter
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