[petsc-dev] error with karlrupp/fix-cuda-streams
Karl Rupp
rupp at iue.tuwien.ac.at
Fri Sep 27 23:55:37 CDT 2019
Hi Mark,
> OK, so now the problem has shifted somewhat in that it now manifests
> itself on small cases. In earlier investigation I was drawn to
> MatTranspose but had a hard time pinning it down. The bug seems more
> stable now or you probably fixed what looks like all the other bugs.
>
> I added print statements with norms of vectors in mg.c (v-cycle) and
> found that the diffs between the CPU and GPU runs came in MatRestrict,
> which calls MatMultTranspose. I added identical print statements in the
> two versions of MatMultTranspose and see this. (pinning to the CPU does
> not seem to make any difference). Note that the problem comes in the 2nd
> iteration where the *output* vector is non-zero coming in (this should
> not matter).
>
> Karl, I zeroed out the output vector (yy) when I come into this method
> and it fixed the problem. This is with -n 4, and this always works with
> -n 3. See the attached process layouts. It looks like this comes when
> you use the 2nd socket.
>
> So this looks like an Nvidia bug. Let me know what you think and I can
> pass it on to ORNL.
Hmm, there were some issues with MatMultTranspose_MPIAIJ at some point.
I've addressed some of them, but I can't confidently say that all of the
issues were fixed. Thus, I don't think it's a problem in NVIDIA's
cuSparse, but rather something we need to fix in PETSc. Note that the
problem shows up with multiple MPI ranks; if it were a problem in
cuSparse, it would show up on a single rank as well.
Best regards,
Karli
> 06:49 /gpfs/alpine/geo127/scratch/adams$ jsrun*-n 4 *-a 4 -c 4 -g 1
> ./ex56 -cells 8,12,16 *-ex56_dm_vec_type cuda -ex56_dm_mat_type aijcusparse*
> [0] 3465 global equations, 1155 vertices
> [0] 3465 equations in vector, 1155 vertices
> 0 SNES Function norm 1.725526579328e+01
> 0 KSP Residual norm 1.725526579328e+01
> 2) call Restrict with |r| = 1.402719214830704e+01
> MatMultTranspose_MPIAIJCUSPARSE |x in| =
> 1.40271921483070e+01
> * MatMultTranspose_MPIAIJ |y in| =
> 0.00000000000000e+00
> * MatMultTranspose_MPIAIJCUSPARSE |a->lvec| =
> 0.00000000000000e+00
> *** MatMultTranspose_MPIAIJCUSPARSE |yy| =
> 3.43436359545813e+00
> MatMultTranspose_MPIAIJCUSPARSE final |yy| =
> 1.29055494844681e+01
> 3) |R| = 1.290554948446808e+01
> 2) call Restrict with |r| = 4.109771717986951e+00
> MatMultTranspose_MPIAIJCUSPARSE |x in| =
> 4.10977171798695e+00
> * MatMultTranspose_MPIAIJ |y in| =
> 0.00000000000000e+00
> * MatMultTranspose_MPIAIJCUSPARSE |a->lvec| =
> 0.00000000000000e+00
> *** MatMultTranspose_MPIAIJCUSPARSE |yy| =
> 1.79415048609144e-01
> MatMultTranspose_MPIAIJCUSPARSE final |yy| =
> 9.01083013948788e-01
> 3) |R| = 9.010830139487883e-01
> 4) |X| = 2.864698671963022e+02
> 5) |x| = 9.763280000911783e+02
> 6) post smooth |x| = 8.940011621494751e+02
> 4) |X| = 8.940011621494751e+02
> 5) |x| = 1.005081556495388e+03
> 6) post smooth |x| = 1.029043994031627e+03
> 1 KSP Residual norm 8.102614049404e+00
> 2) call Restrict with |r| = 4.402603749876137e+00
> MatMultTranspose_MPIAIJCUSPARSE |x in| =
> 4.40260374987614e+00
> * MatMultTranspose_MPIAIJ |y in| =
> 1.29055494844681e+01
> * MatMultTranspose_MPIAIJCUSPARSE |a->lvec| =
> 0.00000000000000e+00
> *** MatMultTranspose_MPIAIJCUSPARSE |yy| =
> 1.68544559626318e+00
> MatMultTranspose_MPIAIJCUSPARSE final |yy| =
> 1.82129824300863e+00
> 3) |R| = 1.821298243008628e+00
> 2) call Restrict with |r| = 1.068309793900564e+00
> MatMultTranspose_MPIAIJCUSPARSE |x in| =
> 1.06830979390056e+00
> MatMultTranspose_MPIAIJ |y in| =
> 9.01083013948788e-01
> MatMultTranspose_MPIAIJCUSPARSE |a->lvec| =
> 0.00000000000000e+00
> *** MatMultTranspose_MPIAIJCUSPARSE |yy| =
> 1.40519177065298e-01
> MatMultTranspose_MPIAIJCUSPARSE final |yy| =
> 1.01853904152812e-01
> 3) |R| = 1.018539041528117e-01
> 4) |X| = 4.949616392884510e+01
> 5) |x| = 9.309440014159884e+01
> 6) post smooth |x| = 5.432486021529479e+01
> 4) |X| = 5.432486021529479e+01
> 5) |x| = 8.246142532204632e+01
> 6) post smooth |x| = 7.605703654091440e+01
> Linear solve did not converge due to DIVERGED_ITS iterations 1
> Nonlinear solve did not converge due to DIVERGED_LINEAR_SOLVE iterations 0
> 06:50 /gpfs/alpine/geo127/scratch/adams$ jsrun -n 4 -a 4 -c 4 -g 1
> ./ex56 -cells 8,12,16
> [0] 3465 global equations, 1155 vertices
> [0] 3465 equations in vector, 1155 vertices
> 0 SNES Function norm 1.725526579328e+01
> 0 KSP Residual norm 1.725526579328e+01
> 2) call Restrict with |r| = 1.402719214830704e+01
> MatMultTranspose_MPIAIJ |x in| =
> 1.40271921483070e+01
> * MatMultTranspose_MPIAIJ |y in| =
> 0.00000000000000e+00
> * MatMultTranspose_MPIAIJ |a->lvec| =
> 0.00000000000000e+00
> *** MatMultTranspose_MPIAIJ |yy| =
> 3.43436359545813e+00
> MatMultTranspose_MPIAIJ final |yy| =
> 1.29055494844681e+01
> 3) |R| = 1.290554948446809e+01
> 2) call Restrict with |r| = 4.109771717986956e+00
> MatMultTranspose_MPIAIJ |x in| =
> 4.10977171798696e+00
> * MatMultTranspose_MPIAIJ |y in| =
> 0.00000000000000e+00
> * MatMultTranspose_MPIAIJ |a->lvec| =
> 0.00000000000000e+00
> *** MatMultTranspose_MPIAIJ |yy| =
> 1.79415048609143e-01
> MatMultTranspose_MPIAIJ final |yy| =
> 9.01083013948789e-01
> 3) |R| = 9.010830139487889e-01
> 4) |X| = 2.864698671963023e+02
> 5) |x| = 9.763280000911785e+02
> 6) post smooth |x| = 8.940011621494754e+02
> 4) |X| = 8.940011621494754e+02
> 5) |x| = 1.005081556495388e+03
> 6) post smooth |x| = 1.029043994031627e+03
> 1 KSP Residual norm 8.102614049404e+00
> 2) call Restrict with |r| = 4.402603749876139e+00
> MatMultTranspose_MPIAIJ |x in| =
> 4.40260374987614e+00
> * MatMultTranspose_MPIAIJ |y in| =
> 1.29055494844681e+01
> * MatMultTranspose_MPIAIJ |a->lvec| =
> 0.00000000000000e+00
> *** MatMultTranspose_MPIAIJ |yy| =
> 4.43650979822523e-01
> MatMultTranspose_MPIAIJ final |yy| =
> 1.18089369006243e+00
> 3) |R| = 1.180893690062426e+00
> 2) call Restrict with |r| = 6.868764720156294e-01
> MatMultTranspose_MPIAIJ |x in| =
> 6.86876472015629e-01
> MatMultTranspose_MPIAIJ |y in| =
> 9.01083013948789e-01
> MatMultTranspose_MPIAIJ |a->lvec| =
> 0.00000000000000e+00
> *** MatMultTranspose_MPIAIJ |yy| =
> 3.36768099045088e-02
> MatMultTranspose_MPIAIJ final |yy| =
> 6.40334376876017e-02
> 3) |R| = 6.403343768760170e-02
> 4) |X| = 2.380471873599142e+01
> 5) |x| = 6.932703848368443e+01
> 6) post smooth |x| = 4.502536862656444e+01
> 4) |X| = 4.502536862656444e+01
> 5) |x| = 7.998534854728734e+01
> 6) post smooth |x| = 7.660075651381680e+01
> Linear solve did not converge due to DIVERGED_ITS iterations 1
> Nonlinear solve did not converge due to DIVERGED_LINEAR_SOLVE iterations 0
> 06:50 /gpfs/alpine/geo127/scratch/adams$
>
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