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Merge pull request #1560 in HDFFV/hdf5 from hdf5-1-10-documentation-only to hdf5_1_10_5

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* commit '5dd2fda18fbbeab95ba44200e48c8202dae65206':
  Modify RELEASE.txt in response to PR comments
  Updated RELEASE.txt with updates regarding HDFFV-10540
This commit is contained in:
Richard Warren
2019-02-18 13:49:35 -06:00
committed by Larry Knox
parent a4b254a92f
commit 0712f746e9
1 changed files with 19 additions and 1 deletions
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20
release_docs/RELEASE.txt
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@@ -201,7 +201,7 @@ 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.
@@ -695,6 +695,24 @@ 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.