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<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE book PUBLIC "-//OASIS//DTD DocBook MathML Module V1.1b1//EN"
"http://www.oasis-open.org/docbook/xml/mathml/1.1CR1/dbmathml.dtd" [
<!ENTITY clCreate_memflagsInc SYSTEM "clCreate_memflagsInc.xml">
]>
<refentry>
<refentryinfo>
<keywordset>
<keyword>clCreateSubDevices</keyword>
</keywordset>
</refentryinfo>
<refmeta>
<refentrytitle>
clCreateSubDevices
</refentrytitle>
<refmiscinfo>
<copyright>
<year>2007-2011</year>
<holder>The Khronos Group Inc.
Permission is hereby granted, free of charge, to any person obtaining a
copy of this software and/or associated documentation files (the
"Materials"), to deal in the Materials without restriction, including
without limitation the rights to use, copy, modify, merge, publish,
distribute, sublicense, and/or sell copies of the Materials, and to
permit persons to whom the Materials are furnished to do so, subject to
the condition that this copyright notice and permission notice shall be included
in all copies or substantial portions of the Materials.</holder>
</copyright>
</refmiscinfo>
<manvolnum>3</manvolnum>
</refmeta>
<!-- ================================ SYNOPSIS -->
<refnamediv id="clCreateSubDevices">
<refname>
clCreateSubDevices
</refname>
<refpurpose>
Creates an array of sub-devices that each reference a non-intersecting set of compute units within <varname>in_device</varname>.
</refpurpose>
</refnamediv>
<refsynopsisdiv xmlns:xlink="http://www.w3.org/1999/xlink"><title></title>
<funcsynopsis>
<funcprototype>
<funcdef>
<link xlink:href="scalarDataTypes.html">cl_int</link> <function>clCreateSubDevices</function>
</funcdef>
<paramdef>
<link xlink:href="abstractDataTypes.html">cl_device_id</link>
<parameter>in_device</parameter>
</paramdef>
<paramdef>const
<link xlink:href="enums.html#cl_device_partition_property">cl_device_partition_property</link>
<parameter>*properties</parameter>
</paramdef>
<paramdef>
<link xlink:href="scalarDataTypes.html">cl_uint</link>
<parameter>num_devices</parameter>
</paramdef>
<paramdef>
<link xlink:href="scalarDataTypes.html">cl_device_id</link>
<parameter>*out_devices</parameter>
</paramdef>
<paramdef><link xlink:href="scalarDataTypes.html">cl_uint</link>
<parameter>*num_devices_ret</parameter>
</paramdef>
</funcprototype>
</funcsynopsis>
</refsynopsisdiv>
<!-- ================================ PARAMETERS -->
<refsect1 id="parameters">
<title>Parameters</title>
<variablelist>
<varlistentry>
<term><varname>in_device</varname></term>
<listitem>
<para>The device to be partitioned.</para>
</listitem>
</varlistentry>
<varlistentry>
<term><varname>properties</varname></term>
<listitem>
<para>
Specifies how <varname>in_device</varname> is to be partition described
by a partition name and its corresponding value. Each partition name
is immediately followed by the corresponding desired value. The list is
terminated with 0. The list of supported partitioning schemes is described
in the table below. Only one of the listed partitioning schemes can be
specified in <varname>properties</varname>.
</para>
<!-- table 5.4 -->
<informaltable frame="all">
<tgroup cols="2" align="left" colsep="1" rowsep="1">
<colspec colname="col1" colnum="1" />
<colspec colname="col2" colnum="2" />
<thead>
<row>
<entry>cl_device_partition_
property enum (Partition value)</entry>
<entry>Description</entry>
</row>
</thead>
<tbody>
<row>
<entry>CL_DEVICE_PARTITION_EQUALLY (unsigned int)</entry>
<entry>
Split the aggregate device into as many smaller
aggregate devices as can be created, each
containing <replaceable>n</replaceable> compute
units. The value <replaceable>n</replaceable> is
passed as the value accompanying this property. If
<replaceable>n</replaceable> does not divide evenly into
<constant>CL_DEVICE_PARTITION_MAX_COMPUTE_UNITS</constant>,
then the remaining compute units are not used.
</entry>
</row>
<row>
<entry>CL_DEVICE_PARTITION_BY_COUNTS (unsigned int)</entry>
<entry>
This property is followed by a
<constant>CL_DEVICE_PARTITION_BY_COUNTS_LIST_END</constant>
terminated list of compute unit counts. For
each nonzero count <replaceable>m</replaceable>
in the list, a sub-device is created with
<replaceable>m</replaceable> compute units in it.
<constant>CL_DEVICE_PARTITION_BY_COUNTS_LIST_END</constant>
is defined to be 0.
<para>
The number of non-zero count
entries in the list may not exceed
<constant>CL_DEVICE_PARTITION_MAX_SUB_DEVICES</constant>.
</para>
<para>
The total number of compute
units specified may not exceed
<constant>CL_DEVICE_PARTITION_MAX_COMPUTE_UNITS</constant>.
</para>
</entry>
</row>
<row>
<entry>CL_DEVICE_PARTITION_BY_-
AFFINITY_DOMAIN (cl_device_affinity_domain)</entry>
<entry>
Split the device into smaller aggregate devices
containing one or more compute units that all share
part of a cache hierarchy. The value accompanying
this property may be drawn from the following list:
<para>
<constant>CL_DEVICE_AFFINITY_DOMAIN_NUMA</constant>
- Split the device into sub-devices comprised of
compute units that share a NUMA node.
</para>
<para>
<constant>CL_DEVICE_AFFINITY_DOMAIN_L4_CACHE</constant>
- Split the device into sub-devices comprised of
compute units that share a level 4 data cache.
</para>
<para>
<constant>CL_DEVICE_AFFINITY_DOMAIN_L3_CACHE</constant>
- Split the device into sub-devices comprised of
compute units that share a level 3 data cache.
</para>
<para>
<constant>CL_DEVICE_AFFINITY_DOMAIN_L2_CACHE</constant>
- Split the device into sub-devices comprised of
compute units that share a level 2 data cache.
</para>
<para>
<constant>CL_DEVICE_AFFINITY_DOMAIN_L1_CACHE</constant>
- Split the device into sub-devices comprised of
compute units that share a level 1 data cache.
</para>
<para>
<constant>CL_DEVICE_AFFINITY_DOMAIN_NEXT_PARTITIONABLE</constant>
- Split the device along the next partitionable
affinity domain. The implementation shall find the
first level along which the device or sub-device
may be further subdivided in the order NUMA,
L4, L3, L2, L1, and partition the device into
sub-devices comprised of compute units that share
memory subsystems at this level.
</para>
<para>
The user may determine what happened by calling
<citerefentry><refentrytitle>clGetDeviceInfo</refentrytitle></citerefentry>
(<constant>CL_DEVICE_PARTITION_TYPE</constant>)
on the sub-devices.
</para>
</entry>
</row>
</tbody>
</tgroup>
</informaltable>
</listitem>
</varlistentry>
<varlistentry>
<term><varname>num_devices</varname></term>
<listitem>
<para>
Size of memory pointed to by <varname>out_devices</varname> specified as
the number of <type>cl_device_id</type> entries.
</para>
</listitem>
</varlistentry>
<varlistentry>
<term><varname>out_devices</varname></term>
<listitem>
<para>
The buffer where the OpenCL sub-devices will be returned. If
<varname>out_devices</varname> is NULL, this argument is ignored. If
<varname>out_devices</varname> is not NULL, <varname>num_devices</varname>
must be greater than or equal to the number of sub-devices that
<varname>device</varname> may be partitioned into according to the
partitioning scheme specified in <varname>properties</varname>.
</para>
</listitem>
</varlistentry>
<varlistentry>
<term><varname>num_devices_ret</varname></term>
<listitem>
<para>
Returns the number of sub-devices that device may be
partitioned into according to the partitioning scheme specified in
<varname>properties</varname>. If <varname>num_devices_ret</varname>
is NULL, it is ignored.
</para>
</listitem>
</varlistentry>
</variablelist>
</refsect1>
<!-- ================================ NOTES -->
<refsect1 id="notes"><title>Notes</title>
<para>
Creates an array of sub-devices that each reference a non-intersecting set of compute
units within <varname>in_device</varname>, according to a partition scheme given
by <varname>properties</varname>. The output sub-devices may be used in every way
that the root (or parent) device can be used, including creating contexts, building
programs, further calls to <function>clCreateSubDevices</function> and creating
command-queues. When a command-queue is created against a sub-device, the commands
enqueued on the queue are executed only on the sub-device.
</para>
</refsect1>
<!-- ================================ ERRORS -->
<refsect1 id="errors"><title>Errors</title>
<para>
Returns <errorname>CL_SUCCESS</errorname> if the partition is created successfully.
Otherwise, it returns a null value with the following error values returned in
<varname>errcode_ret</varname>:
</para>
<itemizedlist mark="disc">
<listitem>
<errorname>CL_INVALID_DEVICE</errorname> if <varname>in_device</varname> is not valid.
</listitem>
<listitem>
<errorname>CL_INVALID_VALUE</errorname> if values specified in
<varname>properties</varname> are not valid or if values specified in
<varname>properties</varname> are valid but not supported by the device.
</listitem>
<listitem>
<errorname>CL_INVALID_VALUE</errorname> if <varname>out_devices</varname> is not
NULL and <varname>num_devices</varname> is less than the number of sub-devices
created by the partition scheme.
</listitem>
<listitem>
<errorname>CL_DEVICE_PARTITION_FAILED</errorname> if the partition name is
supported by the implementation but <varname>in_device</varname> could not be
further partitioned.
</listitem>
<listitem>
<errorname>CL_INVALID_DEVICE_PARTITION_COUNT</errorname> if
the partition name specified in <varname>properties</varname> is
<constant>CL_DEVICE_PARTITION_BY_COUNTS</constant> and the number of sub-devices
requested exceeds <constant>CL_DEVICE_PARTITION_MAX_SUB_DEVICES</constant>
or the total number of compute units requested exceeds
<constant>CL_DEVICE_PARTITION_MAX_COMPUTE_UNITS</constant> for
<varname>in_device</varname>, or the number of compute units requested
for one or more sub-devices is less than zero or the number of sub-devices
requested exceeds <constant>CL_DEVICE_PARTITION_MAX_COMPUTE_UNITS</constant>
for <varname>in_device</varname>.
</listitem>
<listitem>
<errorname>CL_OUT_OF_RESOURCES</errorname> if there is a failure to allocate
resources required by the OpenCL implementation on the device.
</listitem>
<listitem>
<errorname>CL_OUT_OF_HOST_MEMORY</errorname> if there is a failure to allocate
resources required by the OpenCL implementation on the host.
</listitem>
</itemizedlist>
</refsect1>
<!-- ================================ EXAMPLE -->
<!-- DO NOT DELETE IN CASE AN EXAMPLE IS ADDED IN THE FUTURE -->
<!-- -->
<refsect2 id="example1">
<title>
Example
</title>
<para>
A few examples that describe how to specify partition properties in
<varname>properties</varname> argument to <function>clCreateSubDevices</function>
are given below.
</para>
<para>
To partition a device containing 16 compute units into two sub-devices, each containing
8 compute units, pass the following in <varname>properties</varname>:
</para>
<informaltable frame="none">
<tgroup cols="1" align="left" colsep="0" rowsep="0">
<colspec colname="col1" colnum="1" /> <tbody>
<row>
<entry>
{ CL_DEVICE_PARTITION_EQUALLY, 8, 0 }
</entry>
</row>
</tbody>
</tgroup>
</informaltable>
<para>
To partition a device with four compute units into two sub-devices with one sub-device
containing 3 compute units and the other sub-device 1 compute unit, pass the following
in <varname>properties</varname> argument:
</para>
<informaltable frame="none">
<tgroup cols="1" align="left" colsep="0" rowsep="0">
<colspec colname="col1" colnum="1" /> <tbody>
<row>
<entry>
{ CL_DEVICE_PARTITION_BY_COUNTS,
3, 1, CL_DEVICE_PARTITION_BY_COUNTS_LIST_END, 0 }
</entry>
</row>
</tbody>
</tgroup>
</informaltable>
<para>
To split a device along the outermost cache line (if any), pass the following in
<varname>properties</varname> argument:
</para>
<informaltable frame="none">
<tgroup cols="1" align="left" colsep="0" rowsep="0">
<colspec colname="col1" colnum="1" /> <tbody>
<row>
<entry>
{ CL_DEVICE_PARTITION_BY_AFFINITY_DOMAIN,
CL_DEVICE_AFFINITY_DOMAIN_NEXT_PARTITIONABLE, 0 }
</entry>
</row>
</tbody>
</tgroup>
</informaltable>
</refsect2>
<!-- ================================ SPECIFICATION -->
<!-- Set the "uri" attribute in the <olink /> element to the "named destination" for the PDF page
-->
<refsect1 id="specification"><title>Specification</title>
<para>
<imageobject>
<imagedata fileref="pdficon_small1.gif" format="gif" />
</imageobject>
<olink uri="clCreateSubDevices">OpenCL Specification</olink>
</para>
</refsect1>
<!-- ================================ ALSO SEE -->
<refsect1 id="seealso"><title>Also see</title>
<para>
<citerefentry><refentrytitle>clGetDeviceInfo</refentrytitle></citerefentry>
</para>
</refsect1>
<!-- ================================ COPYRIGHT -->
<!-- Content included from copyright.inc.xsl -->
<refsect3 id="Copyright"><title></title>
<imageobject>
<imagedata fileref="KhronosLogo.jpg" format="jpg" />
</imageobject>
<para />
</refsect3>
<!-- 02-Nov-2011 -->
</refentry>
|
