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Reply To: Multi-GPU MPI library is not CUDA-aware

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› Forums › on OpenLB › General Topics › Multi-GPU MPI library is not CUDA-aware › Reply To: Multi-GPU MPI library is not CUDA-aware

October 6, 2025 at 3:29 pm #10767
Adrian
Keymaster

The command outputs (thanks!) all look fine so this may just be the automated check failing despite CUDA-awareness being available. The logic we use to check this


#ifdef PARALLEL_MODE_MPI
#if defined(MPIX_CUDA_AWARE_SUPPORT) && MPIX_CUDA_AWARE_SUPPORT
  if (!MPIX_Query_cuda_support()) {
    clout << "The used MPI Library is not CUDA-aware. Multi-GPU execution will fail." << std::endl;
  }
#endif
#if defined(MPIX_CUDA_AWARE_SUPPORT) && !MPIX_CUDA_AWARE_SUPPORT
  clout << "The used MPI Library is not CUDA-aware. Multi-GPU execution will fail." << std::endl;
#endif
#if !defined(MPIX_CUDA_AWARE_SUPPORT)
  clout << "Unable to check for CUDA-aware MPI support. Multi-GPU execution may fail." << std::endl;
#endif
#endif // PARALLEL_MODE_MPI

can definitely have gaps. Does the program proceed as usual in multi-GPU after this? (If CUDA-awareness is indeed not working for some reason despite the command output I would expect it to instantly segfault on communication).