So the MPI is killing you in going from 8 to 64. (The GPU flop rate scales almost perfectly, but the overall flop rate is only half of what it should be at 64).
> On Jan 25, 2022, at 9:24 PM, Mark Adams <mfad...@lbl.gov> wrote: > > It looks like we have our instrumentation and job configuration in decent > shape so on to scaling with AMG. > In using multiple nodes I got errors with table entries not found, which can > be caused by a buggy MPI, and the problem does go away when I turn GPU aware > MPI off. > Jed's analysis, if I have this right, is that at 0.7T flops we are at about > 35% of theoretical peal wrt memory bandwidth. > I run out of memory with the next step in this study (7 levels of > refinement), with 2M equations per GPU. This seems low to me and we will see > if we can fix this. > So this 0.7Tflops is with only 1/4 M equations so 35% is not terrible. > Here are the solve times with 001, 008 and 064 nodes, and 5 or 6 levels of > refinement. > > out_001_kokkos_Crusher_5_1.txt:KSPSolve 10 1.0 1.2933e+00 1.0 > 4.13e+10 1.1 1.8e+05 8.4e+03 5.8e+02 3 87 86 78 48 100100100100100 248792 > 423857 6840 3.85e+02 6792 3.85e+02 100 > out_001_kokkos_Crusher_6_1.txt:KSPSolve 10 1.0 5.3667e+00 1.0 > 3.89e+11 1.0 2.1e+05 3.3e+04 6.7e+02 2 87 86 79 48 100100100100100 571572 > 700002 7920 1.74e+03 7920 1.74e+03 100 > out_008_kokkos_Crusher_5_1.txt:KSPSolve 10 1.0 1.9407e+00 1.0 > 4.94e+10 1.1 3.5e+06 6.2e+03 6.7e+02 5 87 86 79 47 100100100100100 1581096 > 3034723 7920 6.88e+02 7920 6.88e+02 100 > out_008_kokkos_Crusher_6_1.txt:KSPSolve 10 1.0 7.4478e+00 1.0 > 4.49e+11 1.0 4.1e+06 2.3e+04 7.6e+02 2 88 87 80 49 100100100100100 3798162 > 5557106 9367 3.02e+03 9359 3.02e+03 100 > out_064_kokkos_Crusher_5_1.txt:KSPSolve 10 1.0 2.4551e+00 1.0 > 5.40e+10 1.1 4.2e+07 5.4e+03 7.3e+02 5 88 87 80 47 100100100100100 11065887 > 23792978 8684 8.90e+02 8683 8.90e+02 100 > out_064_kokkos_Crusher_6_1.txt:KSPSolve 10 1.0 1.1335e+01 1.0 > 5.38e+11 1.0 5.4e+07 2.0e+04 9.1e+02 4 88 88 82 49 100100100100100 24130606 > 43326249 11249 4.26e+03 11249 4.26e+03 100 > > On Tue, Jan 25, 2022 at 1:49 PM Mark Adams <mfad...@lbl.gov > <mailto:mfad...@lbl.gov>> wrote: > > Note that Mark's logs have been switching back and forth between > -use_gpu_aware_mpi and changing number of ranks -- we won't have that > information if we do manual timing hacks. This is going to be a routine thing > we'll need on the mailing list and we need the provenance to go with it. > > GPU aware MPI crashes sometimes so to be safe, while debugging, I had it off. > It works fine here so it has been on in the last tests. > Here is a comparison. > > <tt.tar>
