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Diffstat (limited to 'release_docs/RELEASE.txt')
| -rw-r--r-- | release_docs/RELEASE.txt | 20 |
1 files changed, 19 insertions, 1 deletions
diff --git a/release_docs/RELEASE.txt b/release_docs/RELEASE.txt index ff076da..31a80f6 100644 --- a/release_docs/RELEASE.txt +++ b/release_docs/RELEASE.txt @@ -243,7 +243,7 @@ New Features - Changed the default behavior in parallel when reading the same dataset in its entirely (i.e. H5S_ALL dataset selection) which is being read by all the processes collectively. - The dataset mush be contiguous, less than 2GB, and of an atomic datatype. + The dataset must be contiguous, less than 2GB, and of an atomic datatype. The new behavior is the HDF5 library will use an MPI_Bcast to pass the data read from the disk by the root process to the remain processes in the MPI communicator associated with the HDF5 file. @@ -1028,6 +1028,24 @@ Known Problems CPP ptable test fails on VS2017 with Intel compiler, JIRA issue: HDFFV-10628. This test will pass with VS2015 with Intel compiler. + Older MPI libraries such as OpenMPI 2.0.1 and MPICH 2.1.5 were tested + while attempting to resolve the Jira issue: HDFFV-10540. + The known problems of reading or writing > 2GBs when using MPI-2 was + partially resolved with the MPICH library. The proposed support recognizes + IO operations > 2GB and if the datatype is not a derived type, the library + breaks the IO into chunks which can be input or output with the existing + MPI 2 limitations, i.e. size reporting and function API size/count + arguments are restricted to be 32 bit integers. For derived types larger + than 2GB, MPICH 2.1.5 fails while attempting to read or write data. + OpenMPI in contrast, implements MPI-3 APIs even in the older releases + and thus does not suffer from the 32 bit size limitation described here. + OpenMPI releases prior to v3.1.3 appear to have other datatype issues however, + e.g. within a single parallel test (testphdf5) the subtests (cdsetr, eidsetr) + report data verfication errors before eventually aborting. + The most recent versions of OpenMPI (v3.1.3 or newer) have evidently + resolved these isses and parallel HDF5 testing does not currently report + errors though occasional hangs have been observed. + Known problems in previous releases can be found in the HISTORY*.txt files in the HDF5 source. Please report any new problems found to help@hdfgroup.org. |