Re: [OMPI users] OpenMPI slowdown in latency bound application

Nathan, Our application runs many 'cycles' during a single run. Each cycle advances the time slightly and then re-solves the appropriate equations. Each cycle does effectively the same thing over and over. The times I provided were an approximate average time per cycle for the first ~10 cycles (I

Re: [OMPI users] OpenMPI slowdown in latency bound application

Is this overall runtime or solve time? The former is essentially meaningless as it includes all the startup time (launch, connections, etc). Especially since we are talking about seconds here. -Nathan > On Aug 28, 2019, at 9:10 AM, Cooper Burns via users > wrote: > > Peter, > > It looks lik

Re: [OMPI users] OpenMPI slowdown in latency bound application

Peter, It looks like: Node0: rank0, rank1, rank2, etc.. Node1: rank12, rank13, etc etc So the mapping looks good to me. Thanks, Cooper Cooper Burns Senior Research Engineer

Re: [OMPI users] OpenMPI slowdown in latency bound application

On Wed, 28 Aug 2019 09:45:15 -0500 Cooper Burns wrote: > Peter, > > Thanks for your input! > I tried some things: > > *1) The app was placed/pinned differently by the two MPIs. Often this > would probably not cause such a big difference.* > I agree this is unlikely the cause, however I tried va

Re: [OMPI users] OpenMPI slowdown in latency bound application

Peter, Thanks for your input! I tried some things: *1) The app was placed/pinned differently by the two MPIs. Often this would probably not cause such a big difference.* I agree this is unlikely the cause, however I tried various configurations of map-by, bind-to, etc and none of them had any mea

Re: [OMPI users] OpenMPI slowdown in latency bound application

On Tue, 27 Aug 2019 14:36:54 -0500 Cooper Burns via users wrote: > Hello all, > > I have been doing some MPI benchmarking on an Infiniband cluster. > > Specs are: > 12 cores/node > 2.9ghz/core > Infiniband interconnect (TCP also available) > > Some runtime numbers: > 192 cores total: (16 nodes