Yes, they share L2 and L1i. Brice
Le 30/08/2017 02:16, Gilles Gouaillardet a écrit : > Prentice, > > could you please run > lstopo --of=xml > and post the output ? > > a simple workaround could be to bind each task to two consecutive cores > (assuming two consecutive cores share the same FPU, will know for sure > after i check the topology) > that can be achieved with > mpirun --map-by socket:span,PE=2 ... > > if two cores sharing the same FPU also happen to share the same L2 > cache, an other work around would be to bind to a L2 cache. > > Cheers, > > Gilles > > On Wed, Aug 30, 2017 at 6:00 AM, Prentice Bisbal <pbis...@pppl.gov> wrote: >> I'd like to follow up to my own e-mail... >> >> After playing around with the --bind-to options, it seems there is no way to >> do this with AMD CMT processors, since they are actual physical cores, and >> not hardware threads that appear as "logical cores" as with Intel processors >> with hyperthreading. Which, in hindsight, makes perfect sense. >> >> In the BIOS, you can turn reduce the number of cores to match the number of >> FPUs. On the SuperMicro systems I was testing on, the options is called >> "Downcore" (or somethiing like that) and I set to a value of "compute unit" >> >> Prentice >> >> On 08/24/2017 03:11 PM, Prentice Bisbal wrote: >>> OpenMPI Users, >>> >>> I am using AMD processocers with CMT, where two cores constitute a module, >>> and there is only one FPU per module, so each pair of cores has to share a >>> single FPU. I want to use only one core per module so there is no >>> contention between cores in the same module for the single FPU. Is this >>> possible from the command-line using mpirun with the correct binding >>> specifications? If so, how would I do this? >>> >>> I am using OpenMPI 1.10.3. I read the man page regarding the bind-to-core >>> options, and I'm not sure that will do exactly what I want, so I figured I'd >>> ask the experts here. >>> >> _______________________________________________ >> users mailing list >> users@lists.open-mpi.org >> https://lists.open-mpi.org/mailman/listinfo/users > _______________________________________________ > users mailing list > users@lists.open-mpi.org > https://lists.open-mpi.org/mailman/listinfo/users _______________________________________________ users mailing list users@lists.open-mpi.org https://lists.open-mpi.org/mailman/listinfo/users
