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https://github.com/HDFGroup/hdf5.git
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[svn-r5766]
Purpose:
Two new functions and a few copy-edits.
Description:
Added H5Pset/get_small_data_block_size.
Copy edits -- several typographic (spelling) corrections.
Platforms tested:
IE 5
This commit is contained in:
Frank Baker
parent
22677006ca
commit
c84a46f49b
@ -170,6 +170,9 @@ many different parameters to be easily manipulated.
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<li><a href="#Property-GetDxplMpio">H5Pget_dxpl_mpio</a> ||
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<li><a href="#Property-SetDxplMulti">H5Pset_dxpl_multi</a>
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<li><a href="#Property-GetDxplMulti">H5Pget_dxpl_multi</a>
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<br>
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<li><a href="#Property-SetSmallData">H5Pset_small_data_block_size</a>
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<li><a href="#Property-GetSmallData">H5Pget_small_data_block_size</a>
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</ul>
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</td></tr>
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@ -1620,7 +1623,7 @@ facilitate moving easily between them.</i>
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used by file drivers that are capable of using data sieving.
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<p>
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The data sieve buffer is used when performing I/O on datasets
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in the file. Using a buffer which is large anough to hold
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in the file. Using a buffer which is large enough to hold
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several pieces of the dataset being read in for
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hyperslab selections boosts performance by quite a bit.
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<p>
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@ -2167,6 +2170,101 @@ facilitate moving easily between them.</i>
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</dl>
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<hr>
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<dl>
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<dt><strong>Name:</strong> <a name="Property-SetSmallData">H5Pset_small_data_block_size</a>
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<dt><strong>Signature:</strong>
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<dd><em>herr_t</em> <code>H5Pset_small_data_block_size</code>(<em>hid_t</em> <code>fapl_id</code>,
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<em>hsize_t</em> <code>size</code>
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)
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<dt><strong>Purpose:</strong>
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<dd>Sets the size of a contiguous block reserved for small data.
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<dt><strong>Description:</strong>
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<dd><code>H5Pset_small_data_block_size</code> reserves blocks of
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<code>size</code> bytes for the contiguous storage of the raw data
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portion of <em>small</em> datasets.
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The HDF5 library then writes the raw data from small datasets
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to this reserved space, thus reducing unnecessary discontinuities
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within blocks of meta data and improving IO performance.
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<p>
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A small data block is actually allocated the first time a
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qualifying small dataset is written to the file.
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Space for the raw data portion of this small dataset is suballocated
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within the small data block.
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The raw data from each subsequent small dataset is also written to
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the small data block until it is filled; additional small data blocks
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are allocated as required.
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<p>
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The HDF5 library employs an algorithm that determines whether
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IO performance is likely to benefit from the use of this mechanism
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with each dataset as storage space is allocated in the file.
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A larger <code>size</code> will result in this mechanism being
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employed with larger datasets.
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<p>
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The small data block size is set as an allocation property in the
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file access property list identified by <code>fapl_id</code>.
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<p>
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Setting <code>size</code> to zero (<code>0</code>) disables the
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small data block mechanism.
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<dt><strong>Parameters:</strong>
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<dl>
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<dt><em>hid_t</em> <code>fapl_id</code>
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<dd>IN: File access property list identifier .
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<dt><em>hsize_t</em> <code>size</code>
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<dd>IN: Maximum size, in bytes, of the small data block.
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<br>
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The default size is <code>2048</code>.
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</dl>
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<dt><strong>Returns:</strong>
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<dd>Returns a non-negative value if successful;
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otherwise a negative value.
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<!--
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<dt><strong>Non-C API(s):</strong>
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<dd><a href="fortran/h5p_FORTRAN.html#h5pxxx"
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target="FortranWin"><img src="Graphics/FORTRAN.gif" border=0></a>
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--> <!--
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<img src="Graphics/Java.gif">
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<img src="Graphics/C++.gif">
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-->
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</dl>
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<hr>
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<dl>
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<dt><strong>Name:</strong> <a name="Property-GetSmallData">H5Pget_small_data_block_size</a>
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<dt><strong>Signature:</strong>
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<dd><em>herr_t</em> <code>H5Pget_small_data_block_size</code>(<em>hid_t</em> <code>fapl_id</code>,
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<em>hsize_t *</em><code>size</code>
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)
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<dt><strong>Purpose:</strong>
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<dd>Retrieves the current small data block size setting.
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<dt><strong>Description:</strong>
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<dd><code>H5Pget_small_data_block_size</code> retrieves the
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current setting for the size of the small data block.
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<p>
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If the returned value is zero (<code>0</code>), the small data
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block mechanism has been disabled for the file.
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<dt><strong>Parameters:</strong>
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<dl>
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<dt><em>hid_t</em> <code>fapl_id</code>
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<dd>IN: File access property list identifier .
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<dt><em>hsize_t *</em><code>size</code>
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<dd>OUT: Maximum size, in bytes, of the small data block.
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</dl>
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<dt><strong>Returns:</strong>
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<dd>Returns a non-negative value if successful;
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otherwise a negative value.
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<!--
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<dt><strong>Non-C API(s):</strong>
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<dd><a href="fortran/h5p_FORTRAN.html#h5pxxx"
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target="FortranWin"><img src="Graphics/FORTRAN.gif" border=0></a>
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--> <!--
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<img src="Graphics/Java.gif">
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<img src="Graphics/C++.gif">
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-->
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</dl>
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<hr>
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<dl>
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<dt><strong>Name:</strong> <a name="Property-SetPreserve">H5Pset_preserve</a>
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@ -2939,7 +3037,7 @@ facilitate moving easily between them.</i>
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<p>
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The array <code>memb_addr</code> specifies the offsets within the
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virtual address space, from <code>0</code> (zero) to
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<code>HADDR_MAX</code>, at wihch each type of data storage begins.
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<code>HADDR_MAX</code>, at which each type of data storage begins.
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<p>
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If <code>relax</code> is set to <code>TRUE</code> (or <code>1</code>),
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then opening an existing file for read-only access will not fail
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@ -2989,7 +3087,7 @@ facilitate moving easily between them.</i>
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<dt><em>const haddr_t *</em><code>memb_addr</code>
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<dd>IN: The offsets within the virtual address space,
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from <code>0</code> (zero) to <code>HADDR_MAX</code>,
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at wihch each type of data storage begins.
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at which each type of data storage begins.
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<dt><em>hbool_t</em> <code>relax</code>
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<dd>IN: Allows read-only access to incomplete file sets
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when <code>TRUE</code>.
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@ -3176,7 +3274,7 @@ facilitate moving easily between them.</i>
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<dt><strong>Purpose:</strong>
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<dd>Emulates the old split file driver.
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<dt><strong>Description:</strong>
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<dd><code>H5Pset_fapl_split</code> is a compatability function that
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<dd><code>H5Pset_fapl_split</code> is a compatibility function that
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enables the multi-file driver to emulate the split driver from
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HDF5 Releases 1.0 and 1.2.
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The split file driver stored metadata and raw data in separate files
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@ -3458,7 +3556,7 @@ fid=H5Fcreate("PointA",H5F_ACC_TRUNC,H5P_DEFAULT,fapl);
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<dd><code>H5Pset_driver</code> sets the file driver,
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<code>driver_id</code>, for a file access or data transfer
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property list, <code>plist_id</code>, and supplies an
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optional struct containing the driver-specific properites,
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optional struct containing the driver-specific properties,
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<code>driver_info</code>.
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<p>
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<font color=red><b><i>Need <code>driver_info</code> struct definition.</i></b></font>
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@ -3472,7 +3570,7 @@ fid=H5Fcreate("PointA",H5F_ACC_TRUNC,H5P_DEFAULT,fapl);
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<dt><em>hid_t</em> <code>plist_id</code>
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<dd>IN: File access or data transfer property list identifier.
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<dt><em>hid_t</em> <code>driver_id</code>
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<dd>IN: Driver indentifier.
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<dd>IN: Driver identifier.
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<dt><em>const void *</em> <code>driver_info</code>
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<dd>IN: Optional struct containing driver properties.
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</dl>
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@ -3501,7 +3599,7 @@ fid=H5Fcreate("PointA",H5F_ACC_TRUNC,H5P_DEFAULT,fapl);
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<dt><strong>Description:</strong>
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<dd><code>H5Pget_driver</code> returns the identifier of the
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low-level file driver associated with the file access property list
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or data transfer propert list <code>plist_id</code>.
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or data transfer property list <code>plist_id</code>.
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<p>
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Valid driver identifiers with the standard HDF5 library distribution
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include the following:
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@ -3528,7 +3626,7 @@ fid=H5Fcreate("PointA",H5F_ACC_TRUNC,H5P_DEFAULT,fapl);
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<dd>IN: File access or data transfer property list identifier.
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</dl>
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<dt><strong>Returns:</strong>
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<dd>Returns a vaild low-level driver identifier if successful.
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<dd>Returns a valid low-level driver identifier if successful.
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Otherwise returns a negative value.
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<!--
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<dt><strong>Non-C API(s):</strong>
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@ -3996,7 +4094,7 @@ H5P
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<a href="mailto:hdfhelp@ncsa.uiuc.edu">HDF Help Desk</a>
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<br>
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Last modified: 25 April 2002
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Last modified: 5 July 2002
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<br>
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Describes HDF5 Release 1.5, Unreleased Development Branch
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