[petsc-users] Error while running with -pc_type gamg on NVIDIA GPU

[Maruthi NH]

Hi Junchao Zhang,

Thanks for the help. Updating PETSc fixed the problem. However, if I use
boomeramg from hypre as follows, I get a similar error.

./heat_diff_cu --ksp_type gmres -pc_type hypre -pc_hypre_type boomeramg
-use_gpu_aware_mpi 0 -mat_type aijcusparse -vec_type cuda

** On entry to cusparseCreateCsr() parameter number 5 (csrRowOffsets) had
an illegal value: NULL pointer

CUSPARSE ERROR (code = 3, invalid value) at csr_matrix_cuda_utils.c:57

Regards,
Maruthi





On Tue, Sep 12, 2023 at 1:09 AM Junchao Zhang <junchao.zhang at gmail.com>
wrote:

> Hi, Maruthi,
>   I could run your example on my machine.  BTW,  I added these at the end
> of main() to free petsc objects.
> VecDestroy(&vout);
> VecDestroy(&x);
> VecDestroy(&b);
> VecDestroy(&u);
> MatDestroy(&A);
> VecScatterDestroy(&ctx);
> KSPDestroy(&ksp);
>
> If you use cuda-12.2, maybe the problem is already fixed by MR
> https://gitlab.com/petsc/petsc/-/merge_requests/6828
> You can use petsc/main branch to try.  Note your petsc version is from
> Date: 2023-08-13
>
> Thanks.
> --Junchao Zhang
>
>
> On Mon, Sep 11, 2023 at 12:10 PM Maruthi NH <maruthinh at gmail.com> wrote:
>
>> Hi Barry Smith,
>>
>> Thanks for the quick response.
>>
>> Here is the code I used to test PETSc on GPU.
>> This is the command I used to run
>> mpiexec.hydra -n 1 ./heat_diff_cu -Nx 10000000 -ksp_type gmres -mat_type
>> aijcusparse -vec_type cuda -use_gpu_aware_mpi 0 -pc_type gamg
>> -ksp_converged_reason
>>
>> Regards,
>> Maruthi
>>
>>
>>
>> On Sun, Sep 10, 2023 at 11:37 PM Barry Smith <bsmith at petsc.dev> wrote:
>>
>>>
>>>
>>> On Sep 10, 2023, at 5:54 AM, Maruthi NH <maruthinh at gmail.com> wrote:
>>>
>>> Hi all,
>>>
>>> I am trying to accelerate the linear solver with PETSc GPU backend. For
>>> testing I have a simple 1D heat diffusion solver, here are some
>>> observations.
>>> 1. If I use -pc_type gamg it throws the following error
>>>  ** On entry to cusparseCreateCsr() parameter number 5 (csrRowOffsets)
>>> had an illegal value: NULL pointer
>>>
>>> [0]PETSC ERROR: --------------------- Error Message
>>> --------------------------------------------------------------
>>> [0]PETSC ERROR: GPU error
>>> [0]PETSC ERROR: cuSPARSE errorcode 3 (CUSPARSE_STATUS_INVALID_VALUE) :
>>> invalid value
>>> [0]PETSC ERROR: See https://petsc.org/release/faq/ for trouble shooting.
>>> [0]PETSC ERROR: Petsc Development GIT revision: v3.19.4-959-g92f1e92e88
>>>  GIT Date: 2023-08-13 19:43:04 +0000
>>>
>>>    Can you share the code that triggers this?
>>>
>>> 2. Default pc ilu takes about 1.2 seconds on a single CPU and it takes
>>> about 105.9 seconds on a GPU. Similar observations with pc_type asm
>>> I have NVIDIA RTX A2000 8GB Laptop GPU
>>>
>>>
>>>   This is expected. The triangular solves sequentialize on the GPU so
>>> naturally are extremely slow since they cannot take advantage of the
>>> massive parallelism of the GPU.
>>>
>>>
>>> 3. What I could be missing? Also, are there any general guidelines for
>>> better GPU performance using PETSc?
>>>
>>> Regards,
>>> Maruthi
>>>
>>>
>>>
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.mcs.anl.gov/pipermail/petsc-users/attachments/20230912/30b334cf/attachment.html>