I looked at it before and checked again, and still see https://urldefense.us/v3/__https://docs.nvidia.com/deeplearning/nccl/user-gu...
Using both MPI and NCCL to perform transfers between the same sets of CUDA devices concurrently is therefore not guaranteed to be safe.
I was scared by it. It means we have to replace all MPI device communications (what if they are from a third-party library?) with NCCL. --Junchao Zhang On Wed, Apr 17, 2024 at 8:27 AM Sreeram R Venkat <[email protected]> wrote:
Yes, I saw this paper https://urldefense.us/v3/__https://www.sciencedirect.com/science/article/abs... that mentioned it, and I heard in Barry's talk at SIAM PP this year about the need for stream-aware MPI, so I was wondering if NCCL would be used in PETSc to do GPU-GPU communication.
On Wed, Apr 17, 2024, 7:58 AM Junchao Zhang <[email protected]> wrote:
On Wed, Apr 17, 2024 at 7:51 AM Sreeram R Venkat <[email protected]> wrote:
Do you know if there are plans for NCCL support in PETSc?
What is your need? Do you mean using NCCL for the MPI communication?
On Tue, Apr 16, 2024, 10:41 PM Junchao Zhang <[email protected]> wrote:
Glad to hear you found a way. Did you use Frontera at TACC? If yes, I could have a try.
--Junchao Zhang
On Tue, Apr 16, 2024 at 8:35 PM Sreeram R Venkat <[email protected]> wrote:
I finally figured out a way to make it work. I had to build PETSc and my application using the (non GPU-aware) Intel MPI. Then, before running, I switch to the MVAPICH2-GDR. I'm not sure why that works, but it's the only way I've ZjQcmQRYFpfptBannerStart This Message Is From an External Sender This message came from outside your organization.
ZjQcmQRYFpfptBannerEnd I finally figured out a way to make it work. I had to build PETSc and my application using the (non GPU-aware) Intel MPI. Then, before running, I switch to the MVAPICH2-GDR. I'm not sure why that works, but it's the only way I've found to compile and run successfully without throwing any errors about not having a GPU-aware MPI.
On Fri, Dec 8, 2023 at 5:30 PM Mark Adams <[email protected]> wrote:
You may need to set some env variables. This can be system specific so you might want to look at docs or ask TACC how to run with GPU-aware MPI.
Mark
On Fri, Dec 8, 2023 at 5:17 PM Sreeram R Venkat <[email protected]> wrote:
Actually, when I compile my program with this build of PETSc and run, I still get the error:
PETSC ERROR: PETSc is configured with GPU support, but your MPI is not GPU-aware. For better performance, please use a GPU-aware MPI.
I have the mvapich2-gdr module loaded and MV2_USE_CUDA=1.
Is there anything else I need to do?
Thanks, Sreeram
On Fri, Dec 8, 2023 at 3:29 PM Sreeram R Venkat <[email protected]> wrote:
Thank you, changing to CUDA 11.4 fixed the issue. The mvapich2-gdr module didn't require CUDA 11.4 as a dependency, so I was using 12.0
On Fri, Dec 8, 2023 at 1:15 PM Satish Balay <[email protected]> wrote:
Executing: mpicc -show stdout: icc -I/opt/apps/cuda/11.4/include -I/opt/apps/cuda/11.4/include -lcuda -L/opt/apps/cuda/11.4/lib64/stubs -L/opt/apps/cuda/11.4/lib64 -lcudart -lrt -Wl,-rpath,/opt/apps/cuda/11.4/lib64 -Wl,-rpath,XORIGIN/placeholder -Wl,--build-id -L/opt/apps/cuda/11.4/lib64/ -lm -I/opt/apps/intel19/mvapich2-gdr/2.3.7/include -L/opt/apps/intel19/mvapich2-gdr/2.3.7/lib64 -Wl,-rpath -Wl,/opt/apps/intel19/mvapich2-gdr/2.3.7/lib64 -Wl,--enable-new-dtags -lmpi
Checking for program /opt/apps/cuda/12.0/bin/nvcc...found
Looks like you are trying to mix in 2 different cuda versions in this build.
Perhaps you need to use cuda-11.4 - with this install of mvapich..
Satish
On Fri, 8 Dec 2023, Matthew Knepley wrote:
On Fri, Dec 8, 2023 at 1:54 PM Sreeram R Venkat < [email protected]> wrote:
I am trying to build PETSc with CUDA using the CUDA-Aware MVAPICH2-GDR.
Here is my configure command:
./configure PETSC_ARCH=linux-c-debug-mvapich2-gdr --download-hypre --with-cuda=true --cuda-dir=$TACC_CUDA_DIR --with-hdf5=true --with-hdf5-dir=$TACC_PHDF5_DIR --download-elemental --download-metis --download-parmetis --with-cc=mpicc --with-cxx=mpicxx --with-fc=mpif90
which errors with:
UNABLE to CONFIGURE with GIVEN OPTIONS (see configure.log for details):
CUDA compile failed with arch flags " -ccbin mpic++ -std=c++14 -Xcompiler -fPIC -Xcompiler -fvisibility=hidden -g -lineinfo -gencode arch=compute_80,code=sm_80" generated from "--with-cuda-arch=80"
The same configure command works when I use the Intel MPI and I can build with CUDA. The full config.log file is attached. Please let me know if you need any other information. I appreciate your help with this.
The proximate error is
Executing: nvcc -c -o /tmp/petsc-kn3f29gl/config.packages.cuda/conftest.o -I/tmp/petsc-kn3f29gl/config.setCompilers -I/tmp/petsc-kn3f29gl/config.types -I/tmp/petsc-kn3f29gl/config.packages.cuda -ccbin mpic++ -std=c++14 -Xcompiler -fPIC -Xcompiler -fvisibility=hidden -g -lineinfo -gencode arch=compute_80,code=sm_80 /tmp/petsc-kn3f29gl/config.packages.cuda/ conftest.cu <https://urldefense.us/v3/__http://conftest.cu__;!!G_uCfscf7eWS!duKUz7pE9N0adJ-FOW7PLZ_1cSZvYlnqh7J0TIcZN0v8RLplcWxh1YE8Vis29K0cuw_zAvjdK-H9H2JYYuUUKRXxlA$> stdout: /opt/apps/cuda/11.4/include/crt/sm_80_rt.hpp(141): error: more than one instance of overloaded function "__nv_associate_access_property_impl" has "C" linkage 1 error detected in the compilation of "/tmp/petsc-kn3f29gl/config.packages.cuda/conftest.cu <https://urldefense.us/v3/__http://conftest.cu__;!!G_uCfscf7eWS!duKUz7pE9N0adJ-FOW7PLZ_1cSZvYlnqh7J0TIcZN0v8RLplcWxh1YE8Vis29K0cuw_zAvjdK-H9H2JYYuUUKRXxlA$> ". Possible ERROR while running compiler: exit code 1 stderr: /opt/apps/cuda/11.4/include/crt/sm_80_rt.hpp(141): error: more than one instance of overloaded function "__nv_associate_access_property_impl" has "C" linkage
1 error detected in the compilation of "/tmp/petsc-kn3f29gl/config.packages.cuda
This looks like screwed up headers to me, but I will let someone that understands CUDA compilation reply.
Thanks,
Matt
Thanks,
Sreeram