[Hdf-forum] Chunk cache size and performance

[Francesc Alted]

Hi Ger,

2010/1/11 Ger van Diepen <diepen at astron.nl>

> Hi Fransesc,
>
> Why does HDF5 have to reserve space for each IO operation? Space is only
> needed for the cache and the buffer supplied by the caller.
>

You are right, unless the chunk cache is not being used.  For example, on my
previous message,
the tHDF5-x-4KB.png capture has been taken when the HDF5 cache size was set
to just 4 KB, while the chunksize was 8KB, so the chunk cahe cannot be used
(at least I guess so).  At any rate, maybe I was wrong at supposing that
H5FL_reg_free and H5FL_reg_malloc calls where made just to free/malloc space
that is needed to read chunks.

But I agree that a more informed opinion about this would be more than
welcome ;-)

-- 
Francesc Alted
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