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Diffstat (limited to 'src/opencl/qclworksize.cpp')
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diff --git a/src/opencl/qclworksize.cpp b/src/opencl/qclworksize.cpp new file mode 100644 index 0000000..79a351a --- /dev/null +++ b/src/opencl/qclworksize.cpp @@ -0,0 +1,223 @@ +/**************************************************************************** +** +** Copyright (C) 2010 Nokia Corporation and/or its subsidiary(-ies). +** All rights reserved. +** Contact: Nokia Corporation (qt-info@nokia.com) +** +** This file is part of the QtOpenCL module of the Qt Toolkit. +** +** $QT_BEGIN_LICENSE:LGPL$ +** No Commercial Usage +** This file contains pre-release code and may not be distributed. +** You may use this file in accordance with the terms and conditions +** contained in the Technology Preview License Agreement accompanying +** this package. +** +** GNU Lesser General Public License Usage +** Alternatively, this file may be used under the terms of the GNU Lesser +** General Public License version 2.1 as published by the Free Software +** Foundation and appearing in the file LICENSE.LGPL included in the +** packaging of this file. Please review the following information to +** ensure the GNU Lesser General Public License version 2.1 requirements +** will be met: http://www.gnu.org/licenses/old-licenses/lgpl-2.1.html. +** +** In addition, as a special exception, Nokia gives you certain additional +** rights. These rights are described in the Nokia Qt LGPL Exception +** version 1.1, included in the file LGPL_EXCEPTION.txt in this package. +** +** If you have questions regarding the use of this file, please contact +** Nokia at qt-info@nokia.com. +** +** +** +** +** +** +** +** +** $QT_END_LICENSE$ +** +****************************************************************************/ + +#include "qclworksize.h" +#include "qcldevice.h" + +QT_BEGIN_NAMESPACE + +/*! + \class QCLWorkSize + \brief The QCLWorkSize class defines the size of an item of work for an OpenCL kernel. + \since 4.7 + \ingroup opencl + + OpenCL work sizes may be single-dimensional, two-dimensional, + or three-dimensional: + + \code + QCLWorkSize oned(128); + QCLWorkSize twod(16, 16); + QCLWorkSize threed(32, 32, 16); + ... + QCLKernel kernel = ...; + kernel.setGlobalWorkSize(oned); + kernel.setGlobalWorkSize(twod); + kernel.setGlobalWorkSize(threed); + \endcode + + For convenience, QCLKernel::setGlobalWorkSize() and + QCLKernel::setLocalWorkSize() can be specified by a QCLWorkSize + object or direct numeric arguments: + + \code + QCLKernel kernel = ...; + kernel.setGlobalWorkSize(128); + kernel.setGlobalWorkSize(16, 16); + kernel.setGlobalWorkSize(32, 32, 16); + \endcode + + \sa QCLKernel +*/ + +/*! + \fn QCLWorkSize::QCLWorkSize() + + Constructs a default work size consisting of a single dimension + with width() set to 1. +*/ + +/*! + \fn QCLWorkSize::QCLWorkSize(size_t size) + + Constructs a single-dimensional work size with width() set to \a size. + The height() and depth() will be set to 1. +*/ + +/*! + \fn QCLWorkSize::QCLWorkSize(size_t width, size_t height) + + Constructs a two-dimensional work size of \a width x \a height. + The depth() will be set to 1. +*/ + +/*! + \fn QCLWorkSize::QCLWorkSize(const QSize &size) + + Constructs a two-dimensional work size set to \a size. + The depth() will be set to 1. +*/ + +/*! + \fn QCLWorkSize::QCLWorkSize(size_t width, size_t height, size_t depth) + + Constructs a three-dimensional work size of \a width x \a height x + \a depth. +*/ + +/*! + \fn size_t QCLWorkSize::dimensions() const + + Returns the number of dimensions for this work size, 1, 2, or 3. +*/ + +/*! + \fn size_t QCLWorkSize::width() const + + Returns the width of this work size specification. +*/ + +/*! + \fn size_t QCLWorkSize::height() const + + Returns the height of this work size specification. +*/ + +/*! + \fn size_t QCLWorkSize::depth() const + + Returns the depth of this work size specification. +*/ + +/*! + \fn const size_t *QCLWorkSize::sizes() const + + Returns a const pointer to the size array within this object. +*/ + +/*! + \fn bool QCLWorkSize::operator==(const QCLWorkSize &other) const + + Returns true if this work size specification has the same + dimensions as \a other; false otherwise. + + \sa operator!=() +*/ + +/*! + \fn bool QCLWorkSize::operator!=(const QCLWorkSize &other) const + + Returns true if this work size specification does not have + the same dimensions as \a other; false otherwise. + + \sa operator==() +*/ + +static size_t qt_gcd_of_size(size_t x, size_t y) +{ + size_t remainder; + while ((remainder = x % y) != 0) { + x = y; + y = remainder; + } + return y; +} + +/*! + Returns the best-fit local work size that evenly divides this work + size and fits within the maximums defined by \a maxWorkItemSize + and \a maxItemsPerGroup. + + This function is typically used to convert an arbitrary global + work size on a QCLKernel into a compatible local work size. + + \sa QCLKernel::setLocalWorkSize() +*/ +QCLWorkSize QCLWorkSize::toLocalWorkSize + (const QCLWorkSize &maxWorkItemSize, size_t maxItemsPerGroup) const +{ + // Adjust for the maximum work item size in each dimension. + size_t width = m_dim >= 1 ? qt_gcd_of_size(m_sizes[0], maxWorkItemSize.width()) : 1; + size_t height = m_dim >= 2 ? qt_gcd_of_size(m_sizes[1], maxWorkItemSize.height()) : 1; + size_t depth = m_dim >= 3 ? qt_gcd_of_size(m_sizes[2], maxWorkItemSize.depth()) : 1; + + // Reduce in size by a factor of 2 until underneath the maximum group size. + while (maxItemsPerGroup && (width * height * depth) > maxItemsPerGroup) { + width = (width > 1) ? (width / 2) : 1; + height = (height > 1) ? (height / 2) : 1; + depth = (depth > 1) ? (depth / 2) : 1; + } + + // Return the final result. + if (m_dim >= 3) + return QCLWorkSize(width, height, depth); + else if (m_dim >= 2) + return QCLWorkSize(width, height); + else + return QCLWorkSize(width); +} + +/*! + Returns the best-fit local work size that evenly divides this + work size and fits within the maximum work group size of \a device. + + This function is typically used to convert an arbitrary global + work size on a QCLKernel into a compatible local work size. + + \sa QCLKernel::setLocalWorkSize() +*/ +QCLWorkSize QCLWorkSize::toLocalWorkSize(const QCLDevice &device) const +{ + return toLocalWorkSize(device.maximumWorkItemSize(), + device.maximumWorkItemsPerGroup()); +} + +QT_END_NAMESPACE |