On Tue, 2006-11-28 at 09:28 -0800, Matt Leininger wrote: > On Tue, 2006-11-28 at 10:00 -0700, Li-Ta Lo wrote: > > On Mon, 2006-11-27 at 17:21 -0800, Matt Leininger wrote: > > > On Mon, 2006-11-27 at 16:45 -0800, Matt Leininger wrote: > > > > Has anyone testing OMPI's alltoall at > 2000 MPI tasks? I'm seeing each > > > > MPI task eat up > 1GB of memory (just for OMPI - not the app). > > > > > > I gathered some more data using the alltoall benchmark in mpiBench. > > > mpiBench is pretty smart about how large its buffers are. I set it to > > > use <= 100MB. > > > > > > num nodes num MPI tasks system mem mpibench buffer mem > > > 128 1024 1 GB 65 MB > > > 160 1280 1.2 GB 82 MB > > > 192 1536 1.4 GB 98 MB > > > 224 1792 1.6 GB 57 MB > > > 256 2048 1.6-1.8 GB < 100 MB > > > > > > The 256 node run was killed by the OOM for using too much memory. For > > > all these tests the OMPI alltoall is using 1 GB or more of system > > > memory. I know LANL is looking into optimized alltoall, but is anyone > > > looking into the scalability of the memory footprint? > > > > > > > I am the one who is looking into those collective communications. Which > > mca/coll are you using for alltoall? > > The ompi_info output had some mca/coll information in it. I'm not > sure which mca/coll parameter you are interested in. >
Could you try "mpirun -mca coll basic mpibench"? Ollie
