Hi Mark,
On Mar 3, 2010, at 3:47 PM, Mark Miller wrote:
> Am I missing something here?
>
> I thought the intent was to perform sub-allocations out of a larger
> contiguous block so that you could write all the data associated with
> the datasets that went into a 'small block' in a single I/O request.
No, that's not what occurs currently. (Although it might be a logical
outgrowth of the current feature) Currently, it is only trying to reduce
fragmentation of space allocation in the file.
Quincey
> Mark
>
> On Wed, 2010-03-03 at 13:04, Quincey Koziol wrote:
>> Hi Mark,
>>
>> On Mar 3, 2010, at 12:51 PM, Mark Miller wrote:
>>
>>> Hi All,
>>>
>>> I am seeing some behavior in some tests that I am doing that suggests
>>> that on the sec2 vfd (or any vfd I've tried) the small data block size
>>> property (H5Pset_small_data_block_size) is having no effect in changing
>>> I/O requests to underlying system I/O interface.
>>>
>>> Does anyone have experience using this file access property such that
>>> they KNOW FOR CERTAIN it is taking effect and indeed resulting in
>>> different (lower) I/O request frequency to underlying I/O interface?
>>
>> This API routine is only used to "push" allocation of the space for
>> storing small dataset raw data together in the file. It has no effect on
>> I/O requests to the underlying system. H5Pset_sieve_buf_size may help you
>> out though...
>>
>> Quincey
>>
>>
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> --
> Mark C. Miller, Lawrence Livermore National Laboratory
> ================!!LLNL BUSINESS ONLY!!================
> [email protected] urgent: [email protected]
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>
>
> _______________________________________________
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