Hi Quincey,
Yes, it is 1.8.6.
Regards,
John
>From [email protected] Fri Feb 11 18:41:43 2011
>Date: Fri, 11 Feb 2011 16:42:30 -0800
>To: HDF Users Discussion List <[email protected]>
>Subject: Re: [Hdf-forum] Question re: Howison et al Lustre mdc_config tuning
> recommendations
>
>Hi John,
>
>On Feb 10, 2011, at 5:33 PM, John Mainzer wrote:
>
>>> From [email protected] Thu Feb 10 16:48:04 2011
>>> From: Rhys Ulerich <[email protected]>
>>> Date: Thu, 10 Feb 2011 16:48:22 -0600
>>> To: HDF Users Discussion List <[email protected]>
>>> Subject: [Hdf-forum] Question re: Howison et al Lustre mdc_config tuning
>>> recommendations
>>>
>>> Good day,
>>>
>>> I decided to try some metadata caching parameters related to the
>>> discussion on pages 3-4 of Howison et al
>>> (http://www.hdfgroup.org/pubs/papers/howison_hdf5_lustre_iasds2010.pdf).
>>> The paper gives sample code as follows in Figure 5:
>>>
>>> H5AC_cache_config_t mdc_config;
>>> hid_t file_id;
>>> file_id = H5Fopen("file.h5", H5ACC_RDWR, H5P_DEFAULT);
>>> mdc_config.version = H5AC__CURR_CACHE_CONFIG_VERSION;
>>> H5Pget_mdc_config(file_id, &mdc_config)
>>> mdc_config.evictions_enabled = 0 /* FALSE */;
>>> mdc_config.incr_mode = H5C_incr__off;
>>> mdc_config.decr_mode = H5C_decr__off;
>>> H5Pset_mdc_config(file_id, &mdc_config);
>>>
>>> Attempting to directly implement this fails. Modifying the above so
>>> the H5Pget_mdc_config/H5Pset_mdc_config operates on a file access
>>> property list succeeds. However, I saw runtime errors like
>>>
>>> HDF5-DIAG: Error detected in HDF5 (1.8.5-patch1) MPI-process 2:
>>> #000: H5Pfapl.c line 1354 in H5Pset_mdc_config(): invalid metadata
>>> cache configuration
>>> major: Invalid arguments to routine
>>> minor: Bad value
>>> #001: H5AC.c line 2665 in H5AC_validate_config(): Can't disable
>>> evictions while auto-resize is enabled.
>>> major: Invalid arguments to routine
>>> minor: Bad value
>>>
>>> which I've remedied by glancing at H5AC.c:2665 and then adding the statement
>>>
>>> mdc_config.flash_incr_mode = H5C_flash_incr__off;
>>>
>>> to the code block above. Is this modification in the spirit of what
>>> Howison et al. suggests? Or is using H5C_flash_incr__off asking for
>>> trouble in ways that the paper does not discuss?
>>>
>>> Thanks for your time,
>>> Rhys
>>>
>>> _______________________________________________
>>> Hdf-forum is for HDF software users discussion.
>>> [email protected]
>>> http://mail.hdfgroup.org/mailman/listinfo/hdf-forum_hdfgroup.org
>>
>> Hi Rhys,
>>
>> You did exactly as you should have.
>>
>> The metadata cache configuration in the paper worked due to an error
>> on my part when I implemented the flash cache size increment code. I have
>> since noticed and correct the error -- hence the failure you encountered
>> when you tried to duplicate the code from the paper.
>
> Is this fix included in the 1.8.6 release?
>
> Thanks,
> Quincey
>
>> To give you some background:
>>
>> In its default configuration, the metadata cache in HDF5 will attempt to
>> automatically adapt to the current metadata working set size in real time.
>> While there is no fundamental reason why this feature can't be active when
>> evictions are disabled, I can't think of any circumstances in which it would
>> be useful. Further, writing the test code required to verify proper
>> behavior
>> under these circumstances would require significant effort.
>>
>> Hence the decision to require that adaptive metadata cache resizing be
>> disabled when evictions are disabled. Needless to say, this decision will
>> be re-visited if anyone comes up with a plausible reason to do so.
>>
>> Best regards,
>>
>> John Mainzer
>>
>> _______________________________________________
>> Hdf-forum is for HDF software users discussion.
>> [email protected]
>> http://mail.hdfgroup.org/mailman/listinfo/hdf-forum_hdfgroup.org
>
>
>_______________________________________________
>Hdf-forum is for HDF software users discussion.
>[email protected]
>http://mail.hdfgroup.org/mailman/listinfo/hdf-forum_hdfgroup.org
_______________________________________________
Hdf-forum is for HDF software users discussion.
[email protected]
http://mail.hdfgroup.org/mailman/listinfo/hdf-forum_hdfgroup.org
