Fix deadlock for CUDA #4044
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Fix deadlock for CUDA #4044
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asalmgren
approved these changes
Jul 22, 2024
It has been noticed that Tests/GPU/CNS/Exec/RT hangs with `amrex.the_arena_init_size=0 amrex.the_arena_release_threshold=0`. The issue appears to be CUDA host callback functions do not work well with cudaFree in the main host thread. Note that we don't have any CUDA API calls in the host callback function. Also note that cudaMall seems work and using a single GPU stream also works. A workaround is implemented to avoid cudaFree when there are host callback functions inside an MFIter loop.
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It has been noticed that Tests/GPU/CNS/Exec/RT hangs with
amrex.the_arena_init_size=0 amrex.the_arena_release_threshold=0. The issue appears to be CUDA host callback functions do not work well with cudaFree in the main host thread. Note that we don't have any CUDA API calls in the host callback function. Also note that cudaMalloc seems to work and using a single GPU stream also works.A workaround is implemented to avoid cudaFree inside an MFIter loop.