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author | axis <qt-info@nokia.com> | 2009-04-24 11:34:15 (GMT) |
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committer | axis <qt-info@nokia.com> | 2009-04-24 11:34:15 (GMT) |
commit | 8f427b2b914d5b575a4a7c0ed65d2fb8f45acc76 (patch) | |
tree | a17e1a767a89542ab59907462206d7dcf2e504b2 /src/corelib/concurrent/qtconcurrentiteratekernel.cpp | |
download | Qt-8f427b2b914d5b575a4a7c0ed65d2fb8f45acc76.zip Qt-8f427b2b914d5b575a4a7c0ed65d2fb8f45acc76.tar.gz Qt-8f427b2b914d5b575a4a7c0ed65d2fb8f45acc76.tar.bz2 |
Long live Qt for S60!
Diffstat (limited to 'src/corelib/concurrent/qtconcurrentiteratekernel.cpp')
-rw-r--r-- | src/corelib/concurrent/qtconcurrentiteratekernel.cpp | 194 |
1 files changed, 194 insertions, 0 deletions
diff --git a/src/corelib/concurrent/qtconcurrentiteratekernel.cpp b/src/corelib/concurrent/qtconcurrentiteratekernel.cpp new file mode 100644 index 0000000..5c20146 --- /dev/null +++ b/src/corelib/concurrent/qtconcurrentiteratekernel.cpp @@ -0,0 +1,194 @@ +/**************************************************************************** +** +** Copyright (C) 2009 Nokia Corporation and/or its subsidiary(-ies). +** Contact: Qt Software Information (qt-info@nokia.com) +** +** This file is part of the QtCore 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 either Technology Preview License Agreement or the +** Beta Release License Agreement. +** +** 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 1.0, included in the file LGPL_EXCEPTION.txt in this +** package. +** +** GNU General Public License Usage +** Alternatively, this file may be used under the terms of the GNU +** General Public License version 3.0 as published by the Free Software +** Foundation and appearing in the file LICENSE.GPL included in the +** packaging of this file. Please review the following information to +** ensure the GNU General Public License version 3.0 requirements will be +** met: http://www.gnu.org/copyleft/gpl.html. +** +** If you are unsure which license is appropriate for your use, please +** contact the sales department at qt-sales@nokia.com. +** $QT_END_LICENSE$ +** +****************************************************************************/ + +#include "qtconcurrentiteratekernel.h" + +#if defined(Q_OS_MAC) + +#include <mach/mach.h> +#include <mach/mach_time.h> +#include <unistd.h> + +#elif defined(Q_OS_UNIX) + +#include <time.h> +#include <unistd.h> + +#elif defined(Q_OS_WIN) + +#include <windows.h> + +#endif + + +#ifndef QT_NO_CONCURRENT + +QT_BEGIN_NAMESPACE + +enum { + TargetRatio = 100, + MedianSize = 7 +}; + +#if defined(Q_OS_MAC) + +static qint64 getticks() +{ + return mach_absolute_time(); +} + +#elif defined(Q_OS_UNIX) + + +static qint64 getticks() +{ +#if defined(_POSIX_TIMERS) && (_POSIX_TIMERS > 0) + clockid_t clockId; + +#ifndef _POSIX_THREAD_CPUTIME + clockId = CLOCK_REALTIME; +#elif (_POSIX_THREAD_CPUTIME-0 <= 0) + // if we don't have CLOCK_THREAD_CPUTIME_ID, we have to just use elapsed realtime instead + clockId = CLOCK_REALTIME; + +# if (_POSIX_THREAD_CPUTIME-0 == 0) + // detect availablility of CLOCK_THREAD_CPUTIME_ID + static long useThreadCpuTime = -2; + if (useThreadCpuTime == -2) { + // sysconf() will return either -1 or _POSIX_VERSION (don't care about thread races here) + useThreadCpuTime = sysconf(_SC_THREAD_CPUTIME); + } + if (useThreadCpuTime != -1) + clockId = CLOCK_THREAD_CPUTIME_ID; +# endif +#else + clockId = CLOCK_THREAD_CPUTIME_ID; +#endif + + struct timespec ts; + if (clock_gettime(clockId, &ts) == -1) + return 0; + return (ts.tv_sec * 1000000000) + ts.tv_nsec; +#else + // no clock_gettime(), fall back to wall time + struct timeval tv; + gettimeofday(&tv, 0); + return (tv.tv_sec * 1000000) + tv.tv_usec; +#endif +} + +#elif defined(Q_OS_WIN) + +static qint64 getticks() +{ + LARGE_INTEGER x; + if (!QueryPerformanceCounter(&x)) + return 0; + return x.QuadPart; +} + +#endif + +static double elapsed(qint64 after, qint64 before) +{ + return double(after - before); +} + +namespace QtConcurrent { + +/*! \internal + +*/ +BlockSizeManager::BlockSizeManager(int iterationCount) +: maxBlockSize(iterationCount / (QThreadPool::globalInstance()->maxThreadCount() * 2)), + beforeUser(0), afterUser(0), + controlPartElapsed(MedianSize), userPartElapsed(MedianSize), + m_blockSize(1) +{ } + +// Records the time before user code. +void BlockSizeManager::timeBeforeUser() +{ + if (blockSizeMaxed()) + return; + + beforeUser = getticks(); + controlPartElapsed.addValue(elapsed(beforeUser, afterUser)); +} + + // Records the time after user code and adjust the block size if we are spending + // to much time in the for control code compared with the user code. +void BlockSizeManager::timeAfterUser() +{ + if (blockSizeMaxed()) + return; + + afterUser = getticks(); + userPartElapsed.addValue(elapsed(afterUser, beforeUser)); + + if (controlPartElapsed.isMedianValid() == false) + return; + + if (controlPartElapsed.median() * TargetRatio < userPartElapsed.median()) + return; + + m_blockSize = qMin(m_blockSize * 2, maxBlockSize); + +#ifdef QTCONCURRENT_FOR_DEBUG + qDebug() << QThread::currentThread() << "adjusting block size" << controlPartElapsed.median() << userPartElapsed.median() << m_blockSize; +#endif + + // Reset the medians after adjusting the block size so we get + // new measurements with the new block size. + controlPartElapsed.reset(); + userPartElapsed.reset(); +} + +int BlockSizeManager::blockSize() +{ + return m_blockSize; +} + +} // namespace QtConcurrent + +QT_END_NAMESPACE + +#endif // QT_NO_CONCURRENT |