H5Pset_dxpl_mpio_chunk_opt_ratio
(hid_t dxpl_id
,
unsigned percent_proc_per_chunk
)
H5Pset_dxpl_mpio_chunk_opt_ratio
sets a threshold
for the use of collective I/O based on the ratio of processes
with collective access to a dataset with chunked storage.
The decision whether to use collective I/O is made on a per-chunk basis.
The library will calculate the percentage of the total number of
processes, the ratio, that hold selections in each chunk.
If that percentage is greater than the threshold set in
percent_proc_per_chunk
, the library will do collective I/O
for this chunk; otherwise, independent I/O will be done for the chunk.
hid_t dxpl_id |
IN: Data transfer property list identifier |
unsigned percent_proc_per_chunk |
IN: Percent threshold, on the number of processes holding selections per chunk, for performing linked-chunk I/O |