As well as the HDF5 parameter tweaks it is worth investigating if there
are any MPI hints you can pass to improve performance.
The MPI_Info handle you pass to H5Pset_fapl_mpio can have all sorts of
interesting things associated with it. Rather than passing
MPI_INFO_NULL, create a proper info object and do a bit of Googling /
manual reading into your MPI implementation / filesystem to see what is
As an example, you can enable collective buffering within ROMIO and
tweak how it works as such:
ierr = MPI_Info_set( info, "romio_cb_write", "enable");
ierr = MPI_Info_set( info, "cb_buffer_size", "8388609");
ierr = MPI_Info_set( info, "cb_node_size", "96");
We have found settings like this to improve parallel HDF5 performance
Hope that help,
Matt Street MSc MBCS
Parallel Technology Support Tel: +44 (0) 118 982 4528
Supercomputing Solution Centre AWE, Aldermaston, Reading, RG7 4PR. UK.
[mailto:firstname.lastname@example.org] On Behalf Of 4
Sent: 25 August 2009 13:47
Subject: EXTERNAL: [Hdf-forum] Which property parameters will affact
Parellel HDF5 performance ?
Does anyone knows which parameters setting will affect parelle IO
There is so many porperty parameters , such as :
which is exactly effective for PHDF5 performance or used the default
value is always the best. I really cannot understand these parameters.
What I was doing is writing data to hdf5 datasets, when before
writing data, create datasets with the fixed length(contiguous layout),
and write the data to 1 dimension datasets using collective IO(4process,
each process has the approximate size data, uncontiguous access model).
About 20M data will write to a single datasets each time, and about 200
datasets will do the same operation at the same time.
I hope to get much better performance as possible.
Can any one give suggestions on improve performance? And some
hints on how to use above porperty parameters ?
Thanks in advance.
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