Initial support for HDF5 subfiling

franzpoeschel · Dec 22, 2023 · 5212931 · 5212931
1 parent a3fe9b7
commit 5212931
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Showing 2 changed files with 20 additions and 1 deletion.
diff --git a/examples/5_write_parallel.cpp b/examples/5_write_parallel.cpp
@@ -31,7 +31,8 @@ using namespace openPMD;
 
 int main(int argc, char *argv[])
 {
-    MPI_Init(&argc, &argv);
+    int provided;
+    MPI_Init_thread(&argc, &argv, MPI_THREAD_MULTIPLE, &provided);
 
     int mpi_size;
     int mpi_rank;

diff --git a/src/IO/HDF5/ParallelHDF5IOHandler.cpp b/src/IO/HDF5/ParallelHDF5IOHandler.cpp
@@ -21,6 +21,11 @@
 #include "openPMD/IO/HDF5/ParallelHDF5IOHandler.hpp"
 #include "openPMD/IO/HDF5/ParallelHDF5IOHandlerImpl.hpp"
 #include "openPMD/auxiliary/Environment.hpp"
+#include "openPMD/auxiliary/StringManip.hpp"
+
+#ifdef H5_HAVE_SUBFILING_VFD
+#include <H5FDsubfiling.h>
+#endif
 
 #if openPMD_HAVE_MPI
 #include <mpi.h>
@@ -164,6 +169,19 @@ ParallelHDF5IOHandlerImpl::ParallelHDF5IOHandlerImpl(
     VERIFY(
         status >= 0,
         "[HDF5] Internal error: Failed to set HDF5 file access property");
+
+#ifdef H5_HAVE_SUBFILING_VFD
+    int thread_level = 0;
+    MPI_Query_thread(&thread_level);
+    if (thread_level >= MPI_THREAD_MULTIPLE)
+    {
+        H5FD_subfiling_config_t vfd_config;
+        // query default subfiling parameters
+        H5Pget_fapl_subfiling(m_fileAccessProperty, &vfd_config);
+        // ... and set them
+        H5Pset_fapl_subfiling(m_fileAccessProperty, &vfd_config);
+    }
+#endif
 }
 
 ParallelHDF5IOHandlerImpl::~ParallelHDF5IOHandlerImpl()