Is H5F_ACC_TRUNC the right create option for pre-existing files with parallel HDF5 when I want to overwrite the existing file?
Looking at the performance, it seems that one of the most costly actions when running my application is closing out the file, and the top "hot call path" includes the H5FD_mpio_truncate method, and in the comments on that function, it indicates that keeping track of EOF is a costly operation over MPI. Looking through the code, it appears that if I don't use H5F_ACC_TRUNC, it will avoid the overhead of the H5FD_mpio_truncate method. I've used H5F_ACC_TRUNC on serial codes without problems, and it is the option used in several example applications for parallel applications. Is it better to just delete the pre-existing file and then create the file using H5F_ACC_EXCL? Am I missing something here? Jarom Nelson
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