Thanks for the reply, Do you know if you actively include the libnvc library ?! Or is this somehow automatically included ?!
Greetings, Frank > On 4 Apr 2024, at 15:56, Satish Balay <ba...@mcs.anl.gov> wrote: > > > On Thu, 4 Apr 2024, Frank Bramkamp wrote: > >> Dear PETSC Team, >> >> I found the following problem: >> I compile petsc 3.20.5 with Nvidia compiler 23.7. >> >> >> I use a pretty standard configuration, including >> >> --with-cc=mpicc --with-cxx=mpicxx --with-fc=mpifort COPTFLAGS="-O2 -g" >> CXXOPTFLAGS="-O2 -g" FOPTFLAGS="-O2 -g" --with-debugging=0 --with-log=1 >> --download-fblaslapack --with-cuda=0 >> >> I exclude cuda, since I was not sure if the problem was cuda related. > > Can you try using (to exclude cuda): --with-cudac=0 > >> >> >> The problem is now, if I have s simple fortran program where I link the >> petsc library, but I actually do not use petsc in that program >> (Just for testing). I want to use OpenACC directives in my program, e.g. >> !$acc parallel loop . >> The problem is now, as soon I link with the petsc library, the openacc >> commands do not work anymore. >> It seems that openacc is not initialised and hence it cannot find a GPU. >> >> The problem seems that you link with -lnvc. >> In “petscvariables” => PETSC_WITH_EXTERNAL_LIB you include “-lnvc”. >> If I take this out, then openacc works. With “-lnvc” something gets messed >> up. >> >> The problem is also discussed here: >> https://urldefense.us/v3/__https://forums.developer.nvidia.com/t/failed-cuda-device-detection-when-explicitly-linking-libnvc/203225/1__;!!G_uCfscf7eWS!dlXNyKBzSbximQ13OXxwO506OF71yRM_H5KEnarqXE75D6Vg-ePZr2u6SJ5V3YpRETatvb9pMOUVmpyN0-19SFlbug$ >> >> <https://urldefense.us/v3/__https://forums.developer.nvidia.com/t/failed-cuda-device-detection-when-explicitly-linking-libnvc/203225/1__;!!G_uCfscf7eWS!dlXNyKBzSbximQ13OXxwO506OF71yRM_H5KEnarqXE75D6Vg-ePZr2u6SJ5V3YpRETatvb9pMOUVmpyN0-19SFlbug$><https://urldefense.us/v3/__https://forums.developer.nvidia.com/t/failed-cuda-device-detection-when-explicitly-linking-libnvc/203225/1__;!!G_uCfscf7eWS!dlXNyKBzSbximQ13OXxwO506OF71yRM_H5KEnarqXE75D6Vg-ePZr2u6SJ5V3YpRETatvb9pMOUVmpyN0-19SFlbug$ >> >> <https://urldefense.us/v3/__https://forums.developer.nvidia.com/t/failed-cuda-device-detection-when-explicitly-linking-libnvc/203225/1__;!!G_uCfscf7eWS!dlXNyKBzSbximQ13OXxwO506OF71yRM_H5KEnarqXE75D6Vg-ePZr2u6SJ5V3YpRETatvb9pMOUVmpyN0-19SFlbug$> >> > >> >> My understanding is that libnvc is more a runtime library that does not need >> to be included by the linker. >> Not sure if there is a specific reason to include libnvc (I am not so >> familiar what this library does). >> >> If I take out -lnvc from “petscvariables”, then my program with openacc >> works as expected. I did not try any more realistic program that includes >> petsc. >> >> >> >> 2) >> When compiling petsc with cuda support, I also found that in the petsc >> library the library libnvJitLink.so.12 >> Is not found. On my system this library is in $CUDA_ROOT/lib64 >> I am not sure where this library is on your system ?! > > Hm - good if you can send configure.log for this. configure attempts '$CC -v' > to determine the link libraries to get c/c++/fortran compatibility libraries. > But it can grab other libraries that the compilers are using internally here. > > To avoid this - you can explicitly list these libraries to configure. For ex: > for gcc/g++/gfortran > > ./configure CC=gcc CXX=g++ FC=gfortran LIBS="-lgfortran -lstdc++" > > Satish > >> >> >> Thanks a lot, Frank Bramkamp
