[petsc-dev] MatMult on Summit

Mark Adams mfadams at lbl.gov
Sat Sep 21 18:54:14 CDT 2019


These numbers are pretty consistent with what I am seeing with AMG. My
largest case (+....+) attached have a similar number of dof per core (24
cores/node) and I also uses 24 cores/node. Junchao sees almost 20x speed
and I am seeing about 12x, but AMG has coarse grid that are more latency
sensitive. This is from ex56, 3D elasticity with Q1 elements.

On Sat, Sep 21, 2019 at 3:03 PM Zhang, Junchao via petsc-dev <
petsc-dev at mcs.anl.gov> wrote:

> I made the following changes:
> 1) In MatMultAdd_SeqAIJCUSPARSE, use this code sequence at the end
>   ierr = WaitForGPU();CHKERRCUDA(ierr);
>   ierr = PetscLogGpuTimeEnd();CHKERRQ(ierr);
>   ierr = PetscLogGpuFlops(2.0*a->nz);CHKERRQ(ierr);
>   PetscFunctionReturn(0);
> 2) In MatMult_MPIAIJCUSPARSE, use the following code sequence. The old
> code swapped the first two lines. Since with
> -log_view, MatMultAdd_SeqAIJCUSPARSE is blocking, I changed the order to
> have better overlap.
>   ierr =
> VecScatterBegin(a->Mvctx,xx,a->lvec,INSERT_VALUES,SCATTER_FORWARD);CHKERRQ(ierr);
>   ierr = (*a->A->ops->mult)(a->A,xx,yy);CHKERRQ(ierr);
>   ierr =
> VecScatterEnd(a->Mvctx,xx,a->lvec,INSERT_VALUES,SCATTER_FORWARD);CHKERRQ(ierr);
>   ierr = (*a->B->ops->multadd)(a->B,a->lvec,yy,yy);CHKERRQ(ierr);
> 3) Log time directly in the test code so we can also know execution
> time without -log_view (hence cuda synchronization). I manually calculated
> the Total Mflop/s for these cases for easy comparison.
>
> <<Note the CPU versions are copied from yesterday's results>>
>
>
> ------------------------------------------------------------------------------------------------------------------------
> Event                Count      Time (sec)     Flop
>        --- Global ---  --- Stage ----  Total   GPU    - CpuToGpu -   -
> GpuToCpu - GPU
>                    Max Ratio  Max     Ratio   Max  Ratio  Mess   AvgLen
>  Reduct  %T %F %M %L %R  %T %F %M %L %R Mflop/s Mflop/s Count   Size
> Count   Size  %F
>
> ---------------------------------------------------------------------------------------------------------------------------------------------------------------
> 6 MPI ranks,
> MatMult              100 1.0 1.1895e+01 1.0 9.63e+09 1.1 2.8e+03 2.2e+05
> 0.0e+00 24 99 97 18  0 100100100100  0  4743       0      0 0.00e+00    0
> 0.00e+00  0
> VecScatterBegin      100 1.0 4.9145e-02 3.0 0.00e+00 0.0 2.8e+03 2.2e+05
> 0.0e+00  0  0 97 18  0   0  0100100  0     0       0      0 0.00e+00    0
> 0.00e+00  0
> VecScatterEnd        100 1.0 2.9441e+00 133 0.00e+00 0.0 0.0e+00 0.0e+00
> 0.0e+00  3  0  0  0  0  13  0  0  0  0     0       0      0 0.00e+00    0
> 0.00e+00  0
>
> 24 MPI ranks
> MatMult              100 1.0 3.1431e+00 1.0 2.63e+09 1.2 1.9e+04 5.9e+04
> 0.0e+00  8 99 97 25  0 100100100100  0 17948       0      0 0.00e+00    0
> 0.00e+00  0
> VecScatterBegin      100 1.0 2.0583e-02 2.3 0.00e+00 0.0 1.9e+04 5.9e+04
> 0.0e+00  0  0 97 25  0   0  0100100  0     0       0      0 0.00e+00    0
> 0.00e+00  0
> VecScatterEnd        100 1.0 1.0639e+0050.0 0.00e+00 0.0 0.0e+00 0.0e+00
> 0.0e+00  2  0  0  0  0  19  0  0  0  0     0       0      0 0.00e+00    0
> 0.00e+00  0
>
> 42 MPI ranks
> MatMult              100 1.0 2.0519e+00 1.0 1.52e+09 1.3 3.5e+04 4.1e+04
> 0.0e+00 23 99 97 30  0 100100100100  0 27493       0      0 0.00e+00    0
> 0.00e+00  0
> VecScatterBegin      100 1.0 2.0971e-02 3.4 0.00e+00 0.0 3.5e+04 4.1e+04
> 0.0e+00  0  0 97 30  0   1  0100100  0     0       0      0 0.00e+00    0
> 0.00e+00  0
> VecScatterEnd        100 1.0 8.5184e-0162.0 0.00e+00 0.0 0.0e+00 0.0e+00
> 0.0e+00  6  0  0  0  0  24  0  0  0  0     0       0      0 0.00e+00    0
> 0.00e+00  0
>
> 6 MPI ranks + 6 GPUs + regular SF + log_view
> MatMult              100 1.0 1.6863e-01 1.0 9.66e+09 1.1 2.8e+03 2.2e+05
> 0.0e+00  0 99 97 18  0 100100100100  0 335743   629278  100 1.02e+02  100
> 2.69e+02 100
> VecScatterBegin      100 1.0 5.0157e-02 1.6 0.00e+00 0.0 2.8e+03 2.2e+05
> 0.0e+00  0  0 97 18  0  24  0100100  0     0       0      0 0.00e+00  100
> 2.69e+02  0
> VecScatterEnd        100 1.0 4.9155e-02 2.5 0.00e+00 0.0 0.0e+00 0.0e+00
> 0.0e+00  0  0  0  0  0  20  0  0  0  0     0       0      0 0.00e+00    0
> 0.00e+00  0
> VecCUDACopyTo        100 1.0 9.5078e-03 2.0 0.00e+00 0.0 0.0e+00 0.0e+00
> 0.0e+00  0  0  0  0  0   4  0  0  0  0     0       0    100 1.02e+02    0
> 0.00e+00  0
> VecCopyFromSome      100 1.0 2.8485e-02 1.4 0.00e+00 0.0 0.0e+00 0.0e+00
> 0.0e+00  0  0  0  0  0  14  0  0  0  0     0       0      0 0.00e+00  100
> 2.69e+02  0
>
> 6 MPI ranks + 6 GPUs + regular SF  + No log_view
> MatMult:             100 1.0 1.4180e-01
>                                      399268
>
> 6 MPI ranks + 6 GPUs + CUDA-aware SF + log_view
> MatMult              100 1.0 1.1053e-01 1.0 9.66e+09 1.1 2.8e+03 2.2e+05
> 0.0e+00  1 99 97 18  0 100100100100  0 512224   642075    0 0.00e+00    0
> 0.00e+00 100
> VecScatterBegin      100 1.0 8.3418e-03 1.5 0.00e+00 0.0 2.8e+03 2.2e+05
> 0.0e+00  0  0 97 18  0   6  0100100  0     0       0      0 0.00e+00    0
> 0.00e+00  0
> VecScatterEnd        100 1.0 2.2619e-02 1.6 0.00e+00 0.0 0.0e+00 0.0e+00
> 0.0e+00  0  0  0  0  0  16  0  0  0  0     0       0      0 0.00e+00    0
> 0.00e+00  0
>
> 6 MPI ranks + 6 GPUs + CUDA-aware SF + No log_view
> MatMult:             100 1.0 9.8344e-02
>                                      575717
>
> 24 MPI ranks + 6 GPUs + regular SF + log_view
> MatMult              100 1.0 1.1572e-01 1.0 2.63e+09 1.2 1.9e+04 5.9e+04
> 0.0e+00  0 99 97 25  0 100100100100  0 489223   708601  100 4.61e+01  100
> 6.72e+01 100
> VecScatterBegin      100 1.0 2.0641e-02 2.0 0.00e+00 0.0 1.9e+04 5.9e+04
> 0.0e+00  0  0 97 25  0  13  0100100  0     0       0      0 0.00e+00  100
> 6.72e+01  0
> VecScatterEnd        100 1.0 6.8114e-02 5.6 0.00e+00 0.0 0.0e+00 0.0e+00
> 0.0e+00  0  0  0  0  0  38  0  0  0  0     0       0      0 0.00e+00    0
> 0.00e+00  0
> VecCUDACopyTo        100 1.0 6.6646e-03 2.5 0.00e+00 0.0 0.0e+00 0.0e+00
> 0.0e+00  0  0  0  0  0   3  0  0  0  0     0       0    100 4.61e+01    0
> 0.00e+00  0
> VecCopyFromSome      100 1.0 1.0546e-02 1.7 0.00e+00 0.0 0.0e+00 0.0e+00
> 0.0e+00  0  0  0  0  0   7  0  0  0  0     0       0      0 0.00e+00  100
> 6.72e+01  0
>
> 24 MPI ranks + 6 GPUs + regular SF + No log_view
> MatMult:             100 1.0 9.8254e-02
>                                      576201
>
> 24 MPI ranks + 6 GPUs + CUDA-aware SF + log_view
> MatMult              100 1.0 1.1602e-01 1.0 2.63e+09 1.2 1.9e+04 5.9e+04
> 0.0e+00  1 99 97 25  0 100100100100  0 487956   707524    0 0.00e+00    0
> 0.00e+00 100
> VecScatterBegin      100 1.0 2.7088e-02 7.0 0.00e+00 0.0 1.9e+04 5.9e+04
> 0.0e+00  0  0 97 25  0   8  0100100  0     0       0      0 0.00e+00    0
> 0.00e+00  0
> VecScatterEnd        100 1.0 8.4262e-02 3.0 0.00e+00 0.0 0.0e+00 0.0e+00
> 0.0e+00  1  0  0  0  0  52  0  0  0  0     0       0      0 0.00e+00    0
> 0.00e+00  0
>
> 24 MPI ranks + 6 GPUs + CUDA-aware SF + No log_view
> MatMult:             100 1.0 1.0397e-01
>                                      544510
>
>
>
>
>
>
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