> On Jan 21, 2021, at 9:11 PM, Mark Adams <mfad...@lbl.gov> wrote: > > I have tried it and it hangs, but that is expected. This is not something she > has prepared for. > > I am working with Sherry on it. > > And she is fine with just one thread and suggests it if she is in a thread. > > Now that I think about it, I don't understand why she needs OpenMP if she can > live with OMP_NUM_THREADS=1.
It is very possible it was just a coding decision by one of her students and with a few ifdef in her code should would not need the OpenMP but I don't have the time or energy to check her code and design decision. Barry > > Mark > > > > On Thu, Jan 21, 2021 at 9:30 PM Barry Smith <bsm...@petsc.dev > <mailto:bsm...@petsc.dev>> wrote: > > >> On Jan 21, 2021, at 5:37 PM, Mark Adams <mfad...@lbl.gov >> <mailto:mfad...@lbl.gov>> wrote: >> >> This did not work. I verified that MPI_Init_thread is being called correctly >> and that MPI returns that it supports this highest level of thread safety. >> >> I am going to ask ORNL. >> >> And if I use: >> >> -fieldsplit_i1_ksp_norm_type none >> -fieldsplit_i1_ksp_max_it 300 >> >> for all 9 "i" variables, I can run normal iterations on the 10th variable, >> in a 10 species problem, and it works perfectly with 10 threads. >> >> So it is definitely that VecNorm is not thread safe. >> >> And, I want to call SuperLU_dist, which uses threads, but I don't want >> SuperLU to start using threads. Is there a way to tell superLU that there >> are no threads but have PETSc use them? > > My interpretation and Satish's for many years is that SuperLU_DIST has to > be built with and use OpenMP in order to work with CUDA. > > def formCMakeConfigureArgs(self): > args = config.package.CMakePackage.formCMakeConfigureArgs(self) > if self.openmp.found: > self.usesopenmp = 'yes' > else: > args.append('-DCMAKE_DISABLE_FIND_PACKAGE_OpenMP=TRUE') > if self.cuda.found: > if not self.openmp.found: > raise RuntimeError('SuperLU_DIST GPU code currently requires OpenMP. > Use --with-openmp=1') > > But this could be ok. You use OpenMP and then it uses OpenMP internally, each > doing their own business (what could go wrong :-)). > > Have you tried it? > > Barry > > >> >> Thanks, >> Mark >> >> On Thu, Jan 21, 2021 at 5:19 PM Mark Adams <mfad...@lbl.gov >> <mailto:mfad...@lbl.gov>> wrote: >> OK, the problem is probably: >> >> PetscMPIInt PETSC_MPI_THREAD_REQUIRED = MPI_THREAD_FUNNELED; >> >> There is an example that sets: >> >> PETSC_MPI_THREAD_REQUIRED = MPI_THREAD_MULTIPLE; >> >> This is what I need. >> >> >> >> >> On Thu, Jan 21, 2021 at 2:26 PM Mark Adams <mfad...@lbl.gov >> <mailto:mfad...@lbl.gov>> wrote: >> >> >> On Thu, Jan 21, 2021 at 2:11 PM Matthew Knepley <knep...@gmail.com >> <mailto:knep...@gmail.com>> wrote: >> On Thu, Jan 21, 2021 at 2:02 PM Mark Adams <mfad...@lbl.gov >> <mailto:mfad...@lbl.gov>> wrote: >> On Thu, Jan 21, 2021 at 1:44 PM Matthew Knepley <knep...@gmail.com >> <mailto:knep...@gmail.com>> wrote: >> On Thu, Jan 21, 2021 at 11:16 AM Mark Adams <mfad...@lbl.gov >> <mailto:mfad...@lbl.gov>> wrote: >> Yes, the problem is that each KSP solver is running in an OMP thread (So at >> this point it only works for SELF and its Landau so it is all I need). It >> looks like MPI reductions called with a comm_self are not thread safe (eg, >> the could say, this is one proc, thus, just copy send --> recv, but they >> don't) >> >> Instead of using SELF, how about Comm_dup() for each thread? >> >> OK, raw MPI_Comm_dup. I tried PetscCommDup. Let me this. >> Thanks, >> >> You would have to dup them all outside the OMP section, since it is not >> threadsafe. Then each thread uses one I think. >> >> Yea sure. I do it in SetUp. >> >> Well that worked to get different Comms, finally, I still get the same >> problem. The number of iterations differ wildly. This two species and two >> threads (13 SNES its that is not deterministic). Way below is one thread (8 >> its) and fairly uniform iteration counts. >> >> Maybe this MPI is just not thread safe at all. Let me look into it. >> Thanks anyway, >> >> 0 SNES Function norm 4.974994975313e-03 >> In PCFieldSplitSetFields_FieldSplit with -------------- link: 0x80017c60. >> Comms pc=0x67ad27c0 ksp=0x7ffe1600 newcomm=0x8014b6e0 >> In PCFieldSplitSetFields_FieldSplit with -------------- link: 0x7ffdabc0. >> Comms pc=0x67ad27c0 ksp=0x7fff70d0 newcomm=0x7ffe9980 >> Linear fieldsplit_e_ solve converged due to CONVERGED_RTOL iterations >> 282 >> 1 SNES Function norm 1.836376279964e-05 >> Linear fieldsplit_e_ solve converged due to CONVERGED_ATOL iterations >> 19 >> 2 SNES Function norm 3.059930074740e-07 >> Linear fieldsplit_e_ solve converged due to CONVERGED_ATOL iterations >> 15 >> 3 SNES Function norm 4.744275398121e-08 >> Linear fieldsplit_e_ solve converged due to CONVERGED_ATOL iterations 4 >> 4 SNES Function norm 4.014828563316e-08 >> Linear fieldsplit_e_ solve converged due to CONVERGED_RTOL iterations >> 456 >> 5 SNES Function norm 5.670836337808e-09 >> Linear fieldsplit_e_ solve converged due to CONVERGED_ATOL iterations 2 >> 6 SNES Function norm 2.410421401323e-09 >> Linear fieldsplit_e_ solve converged due to CONVERGED_ATOL iterations >> 18 >> 7 SNES Function norm 6.533948191791e-10 >> Linear fieldsplit_e_ solve converged due to CONVERGED_RTOL iterations >> 458 >> 8 SNES Function norm 1.008133815842e-10 >> Linear fieldsplit_e_ solve converged due to CONVERGED_ATOL iterations 9 >> 9 SNES Function norm 1.690450876038e-11 >> Linear fieldsplit_e_ solve converged due to CONVERGED_ATOL iterations 4 >> 10 SNES Function norm 1.336383986009e-11 >> Linear fieldsplit_e_ solve converged due to CONVERGED_RTOL iterations >> 463 >> 11 SNES Function norm 1.873022410774e-12 >> Linear fieldsplit_e_ solve converged due to CONVERGED_RTOL iterations >> 113 >> 12 SNES Function norm 1.801834606518e-13 >> Linear fieldsplit_e_ solve converged due to CONVERGED_ATOL iterations 1 >> 13 SNES Function norm 1.004397317339e-13 >> Nonlinear solve converged due to CONVERGED_SNORM_RELATIVE iterations 13 >> >> >> >> >> 0 SNES Function norm 4.974994975313e-03 >> In PCFieldSplitSetFields_FieldSplit with -------------- link: 0x6e265010. >> Comms pc=0x56450340 ksp=0x6e2168d0 newcomm=0x6e265090 >> In PCFieldSplitSetFields_FieldSplit with -------------- link: 0x6e25bc40. >> Comms pc=0x56450340 ksp=0x6e22c1d0 newcomm=0x6e21e8f0 >> Linear fieldsplit_e_ solve converged due to CONVERGED_RTOL iterations >> 282 >> 1 SNES Function norm 1.836376279963e-05 >> Linear fieldsplit_e_ solve converged due to CONVERGED_RTOL iterations >> 380 >> 2 SNES Function norm 3.018499983019e-07 >> Linear fieldsplit_e_ solve converged due to CONVERGED_RTOL iterations >> 387 >> 3 SNES Function norm 1.826353175637e-08 >> Linear fieldsplit_e_ solve converged due to CONVERGED_RTOL iterations >> 391 >> 4 SNES Function norm 1.378600599548e-09 >> Linear fieldsplit_e_ solve converged due to CONVERGED_RTOL iterations >> 392 >> 5 SNES Function norm 1.077289085611e-10 >> Linear fieldsplit_e_ solve converged due to CONVERGED_RTOL iterations >> 394 >> 6 SNES Function norm 8.571891727748e-12 >> Linear fieldsplit_e_ solve converged due to CONVERGED_RTOL iterations >> 395 >> 7 SNES Function norm 6.897647643450e-13 >> Linear fieldsplit_e_ solve converged due to CONVERGED_RTOL iterations >> 395 >> 8 SNES Function norm 5.606434614114e-14 >> Nonlinear solve converged due to CONVERGED_SNORM_RELATIVE iterations 8 >> >> >> >> >> >> >> >> >> >> Matt >> >> Matt >> >> On Thu, Jan 21, 2021 at 10:46 AM Matthew Knepley <knep...@gmail.com >> <mailto:knep...@gmail.com>> wrote: >> On Thu, Jan 21, 2021 at 10:34 AM Mark Adams <mfad...@lbl.gov >> <mailto:mfad...@lbl.gov>> wrote: >> It looks like PETSc is just too clever for me. I am trying to get a >> different MPI_Comm into each block, but PETSc is thwarting me: >> >> It looks like you are using SELF. Is that what you want? Do you want a bunch >> of comms with the same group, but independent somehow? I am confused. >> >> Matt >> >> if (jac->use_openmp) { >> ierr = KSPCreate(MPI_COMM_SELF,&ilink->ksp);CHKERRQ(ierr); >> PetscPrintf(PETSC_COMM_SELF,"In PCFieldSplitSetFields_FieldSplit with >> -------------- link: %p. Comms %p >> %p\n",ilink,PetscObjectComm((PetscObject)pc),PetscObjectComm((PetscObject)ilink->ksp)); >> } else { >> ierr = >> KSPCreate(PetscObjectComm((PetscObject)pc),&ilink->ksp);CHKERRQ(ierr); >> } >> >> produces: >> >> In PCFieldSplitSetFields_FieldSplit with -------------- link: 0x7e9cb4f0. >> Comms 0x660c6ad0 0x660c6ad0 >> In PCFieldSplitSetFields_FieldSplit with -------------- link: 0x7e88f7d0. >> Comms 0x660c6ad0 0x660c6ad0 >> >> How can I work around this? >> >> >> On Thu, Jan 21, 2021 at 7:41 AM Mark Adams <mfad...@lbl.gov >> <mailto:mfad...@lbl.gov>> wrote: >> >> >> On Wed, Jan 20, 2021 at 6:21 PM Barry Smith <bsm...@petsc.dev >> <mailto:bsm...@petsc.dev>> wrote: >> >> >>> On Jan 20, 2021, at 3:09 PM, Mark Adams <mfad...@lbl.gov >>> <mailto:mfad...@lbl.gov>> wrote: >>> >>> So I put in a temporary hack to get the first Fieldsplit apply to NOT use >>> OMP and it sort of works. >>> >>> Preonly/lu is fine. GMRES calls vector creates/dups in every solve so that >>> is a big problem. >> >> It should definitely not be creating vectors "in every" solve. But it does >> do lazy allocation of needed restarted vectors which may make it look like >> it is creating "every" vectors in every solve. You can use >> -ksp_gmres_preallocate to force it to create all the restart vectors up >> front at KSPSetUp(). >> >> Well, I run the first solve w/o OMP and I see Vec dups in cuSparse Vecs in >> the 2nd solve. >> >> >> Why is creating vectors "at every solve" a problem? It is not thread safe >> I guess? >> >> It dies when it looks at the options database, in a Free in the get-options >> method to be exact (see stacks). >> >> ======= Backtrace: ========= >> /lib64/libc.so.6(cfree+0x4a0)[0x200021839be0] >> /gpfs/alpine/csc314/scratch/adams/petsc/arch-summit-opt-gnu-cuda-omp/lib/libpetsc.so.3.014(PetscFreeAlign+0x4c)[0x2000002a368c] >> /gpfs/alpine/csc314/scratch/adams/petsc/arch-summit-opt-gnu-cuda-omp/lib/libpetsc.so.3.014(PetscOptionsEnd_Private+0xf4)[0x2000002e53f0] >> /gpfs/alpine/csc314/scratch/adams/petsc/arch-summit-opt-gnu-cuda-omp/lib/libpetsc.so.3.014(+0x7c6c28)[0x2000008b6c28] >> /gpfs/alpine/csc314/scratch/adams/petsc/arch-summit-opt-gnu-cuda-omp/lib/libpetsc.so.3.014(VecCreate_SeqCUDA+0x11c)[0x20000052c510] >> /gpfs/alpine/csc314/scratch/adams/petsc/arch-summit-opt-gnu-cuda-omp/lib/libpetsc.so.3.014(VecSetType+0x670)[0x200000549664] >> /gpfs/alpine/csc314/scratch/adams/petsc/arch-summit-opt-gnu-cuda-omp/lib/libpetsc.so.3.014(VecCreateSeqCUDA+0x150)[0x20000052c0b0] >> /gpfs/alpine/csc314/scratch/adams/petsc/arch-summit-opt-gnu-cuda-omp/lib/libpetsc.so.3.014(+0x43c198)[0x20000052c198] >> /gpfs/alpine/csc314/scratch/adams/petsc/arch-summit-opt-gnu-cuda-omp/lib/libpetsc.so.3.014(VecDuplicate+0x44)[0x200000542168] >> /gpfs/alpine/csc314/scratch/adams/petsc/arch-summit-opt-gnu-cuda-omp/lib/libpetsc.so.3.014(VecDuplicateVecs_Default+0x148)[0x200000543820] >> /gpfs/alpine/csc314/scratch/adams/petsc/arch-summit-opt-gnu-cuda-omp/lib/libpetsc.so.3.014(VecDuplicateVecs+0x54)[0x2000005425f4] >> /gpfs/alpine/csc314/scratch/adams/petsc/arch-summit-opt-gnu-cuda-omp/lib/libpetsc.so.3.014(KSPCreateVecs+0x4b4)[0x2000016f0aec] >> >> >> >>> Richardson works except the convergence test gets confused, presumably >>> because MPI reductions with PETSC_COMM_SELF is not threadsafe. >> >>> >>> One fix for the norms might be to create each subdomain solver with a >>> different communicator. >> >> Yes you could do that. It might actually be the correct thing to do also, >> if you have multiple threads call MPI reductions on the same communicator >> that would be a problem. Each KSP should get a new MPI_Comm. >> >> OK. I will only do this. >> >> >> >> -- >> What most experimenters take for granted before they begin their experiments >> is infinitely more interesting than any results to which their experiments >> lead. >> -- Norbert Wiener >> >> https://www.cse.buffalo.edu/~knepley/ <http://www.cse.buffalo.edu/~knepley/> >> >> >> -- >> What most experimenters take for granted before they begin their experiments >> is infinitely more interesting than any results to which their experiments >> lead. >> -- Norbert Wiener >> >> https://www.cse.buffalo.edu/~knepley/ <http://www.cse.buffalo.edu/~knepley/> >> >> >> -- >> What most experimenters take for granted before they begin their experiments >> is infinitely more interesting than any results to which their experiments >> lead. >> -- Norbert Wiener >> >> https://www.cse.buffalo.edu/~knepley/ <http://www.cse.buffalo.edu/~knepley/> >
