It is using the hash map system for inserting values which only inserts on the CPU, not on the GPU. So I don't see that it would be moving any data to the GPU until the mat assembly() is done which it never gets to. Hence I have trouble understanding why the GPU has anything to do with the crash.
I guess I need to try to reproduce it on a GPU system. Barry > On Jan 18, 2024, at 4:28 PM, Matthew Knepley <[email protected]> wrote: > > On Thu, Jan 18, 2024 at 4:18 PM Yesypenko, Anna <[email protected] > <mailto:[email protected]>> wrote: >> Hi Matt, Barry, >> >> Apologies for the extra dependency on scipy. I can replicate the error by >> calling setValue (i,j,v) in a loop as well. >> In roughly half of 10 runs, the following script fails because of an error >> in hashmapijv – the same as my original post. >> It successfully runs without error the other times. >> >> Barry is right that it's CUDA specific. The script runs fine on the CPU. >> Do you have any suggestions or example scripts on assigning entries to a >> AIJCUSPARSE matrix? > > Oh, you definitely do not want to be doing this. I believe you would rather > > 1) Make the CPU matrix and then convert to AIJCUSPARSE. This is efficient. > > 2) Produce the values on the GPU and call > > https://petsc.org/main/manualpages/Mat/MatSetPreallocationCOO/ > https://petsc.org/main/manualpages/Mat/MatSetValuesCOO/ > > This is what most people do who are forming matrices directly on the GPU. > > What you are currently doing is incredibly inefficient, and I think accounts > for you running out of memory. > It talks back and forth between the CPU and GPU. > > Thanks, > > Matt > >> Here is a minimum snippet that doesn't depend on scipy. >> ``` >> from petsc4py import PETSc >> import numpy as np >> >> n = int(5e5); >> nnz = 3 * np.ones(n, dtype=np.int32) >> nnz[0] = nnz[-1] = 2 >> A = PETSc.Mat(comm=PETSc.COMM_WORLD) >> A.createAIJ(size=[n,n],comm=PETSc.COMM_WORLD,nnz=nnz) >> A.setType('aijcusparse') >> >> A.setValue(0, 0, 2) >> A.setValue(0, 1, -1) >> A.setValue(n-1, n-2, -1) >> A.setValue(n-1, n-1, 2) >> >> for index in range(1, n - 1): >> A.setValue(index, index - 1, -1) >> A.setValue(index, index, 2) >> A.setValue(index, index + 1, -1) >> A.assemble() >> ``` >> If it means anything to you, when the hash error occurs, it is for index >> 67283 after filling 201851 nonzero values. >> >> Thank you for your help and suggestions! >> Anna >> >> From: Barry Smith <[email protected] <mailto:[email protected]>> >> Sent: Thursday, January 18, 2024 2:35 PM >> To: Yesypenko, Anna <[email protected] <mailto:[email protected]>> >> Cc: [email protected] <mailto:[email protected]> >> <[email protected] <mailto:[email protected]>> >> Subject: Re: [petsc-users] HashMap Error when populating AIJCUSPARSE matrix >> >> >> Do you ever get a problem with 'aij` ? Can you run in a loop with 'aij' >> to confirm it doesn't fail then? >> >> >> >> Barry >> >> >>> On Jan 17, 2024, at 4:51 PM, Yesypenko, Anna <[email protected] >>> <mailto:[email protected]>> wrote: >>> >>> Dear Petsc users/developers, >>> >>> I'm experiencing a bug when using petsc4py with GPU support. It may be my >>> mistake in how I set up a AIJCUSPARSE matrix. >>> For larger matrices, I sometimes encounter a error in assigning matrix >>> values; the error is thrown in PetscHMapIJVQuerySet(). >>> Here is a minimum snippet that populates a sparse tridiagonal matrix. >>> >>> ``` >>> from petsc4py import PETSc >>> from scipy.sparse import diags >>> import numpy as np >>> >>> n = int(5e5); >>> >>> nnz = 3 * np.ones(n, dtype=np.int32); nnz[0] = nnz[-1] = 2 >>> A = PETSc.Mat(comm=PETSc.COMM_WORLD) >>> A.createAIJ(size=[n,n],comm=PETSc.COMM_WORLD,nnz=nnz) >>> A.setType('aijcusparse') >>> tmp = diags([-1,2,-1],[-1,0,+1],shape=(n,n)).tocsr() >>> A.setValuesCSR(tmp.indptr,tmp.indices,tmp.data) >>> ####### this is the line where the error is thrown. >>> A.assemble() >>> ``` >>> >>> The error trace is below: >>> ``` >>> File "petsc4py/PETSc/Mat.pyx", line 2603, in petsc4py.PETSc.Mat.setValuesCSR >>> File "petsc4py/PETSc/petscmat.pxi", line 1039, in >>> petsc4py.PETSc.matsetvalues_csr >>> File "petsc4py/PETSc/petscmat.pxi", line 1032, in >>> petsc4py.PETSc.matsetvalues_ijv >>> petsc4py.PETSc.Error: error code 76 >>> [0] MatSetValues() at >>> /work/06368/annayesy/ls6/petsc/src/mat/interface/matrix.c:1497 >>> [0] MatSetValues_Seq_Hash() at >>> /work/06368/annayesy/ls6/petsc/include/../src/mat/impls/aij/seq/seqhashmatsetvalues.h:52 >>> [0] PetscHMapIJVQuerySet() at >>> /work/06368/annayesy/ls6/petsc/include/petsc/private/hashmapijv.h:10 >>> [0] Error in external library >>> [0] [khash] Assertion: `ret >= 0' failed. >>> ``` >>> >>> If I run the same script a handful of times, it will run without errors >>> eventually. >>> Does anyone have insight on why it is behaving this way? I'm running on a >>> node with 3x NVIDIA A100 PCIE 40GB. >>> >>> Thank you! >>> Anna >> > > > -- > 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/>
