qbenchmark.cpp

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// Copyright (C) 2016 The Qt Company Ltd.
// SPDX-License-Identifier: LicenseRef-Qt-Commercial OR LGPL-3.0-only OR GPL-2.0-only OR GPL-3.0-only
 
#include <QtTest/qbenchmark.h>
#include <QtTest/private/qbenchmark_p.h>
#include <QtTest/private/qbenchmarkmetric_p.h>
#include <QtTest/private/qbenchmarktimemeasurers_p.h>
 
#include <QtCore/qdir.h>
#include <QtCore/qset.h>
#include <QtCore/qdebug.h>
 
QT_BEGIN_NAMESPACE
 
QBenchmarkGlobalData *QBenchmarkGlobalData::current;
 
QBenchmarkGlobalData::QBenchmarkGlobalData()
{
    setMode(mode_);
}
 
QBenchmarkGlobalData::~QBenchmarkGlobalData()
{
    delete measurer;
    if (QBenchmarkGlobalData::current == this)
        QBenchmarkGlobalData::current = nullptr;
}
 
void QBenchmarkGlobalData::setMode(Mode mode)
{
    mode_ = mode;
 
    delete measurer;
    measurer = createMeasurer();
}
 
QBenchmarkMeasurerBase * QBenchmarkGlobalData::createMeasurer()
{
    QBenchmarkMeasurerBase *measurer = nullptr;
    if (0) {
#if QT_CONFIG(valgrind)
    } else if (mode_ == CallgrindChildProcess || mode_ == CallgrindParentProcess) {
        measurer = new QBenchmarkCallgrindMeasurer;
#endif
#ifdef QTESTLIB_USE_PERF_EVENTS
    } else if (mode_ == PerfCounter) {
        measurer = new QBenchmarkPerfEventsMeasurer;
#endif
#ifdef HAVE_TICK_COUNTER
    } else if (mode_ == TickCounter) {
        measurer = new QBenchmarkTickMeasurer;
#endif
    } else if (mode_ == EventCounter) {
        measurer = new QBenchmarkEvent;
    } else {
        measurer =  new QBenchmarkTimeMeasurer;
    }
    return measurer;
}
 
int QBenchmarkGlobalData::adjustMedianIterationCount()
{
    return medianIterationCount != -1
        ? medianIterationCount : measurer->adjustMedianCount(1);
}
 
 
QBenchmarkTestMethodData *QBenchmarkTestMethodData::current;
 
QBenchmarkTestMethodData::QBenchmarkTestMethodData() = default;
 
QBenchmarkTestMethodData::~QBenchmarkTestMethodData()
{
    QBenchmarkTestMethodData::current = nullptr;
}
 
void QBenchmarkTestMethodData::beginDataRun()
{
    iterationCount = initialIterationCount(1);
}
 
void QBenchmarkTestMethodData::endDataRun()
{
}
 
/*!
    \internal
    Initial iteration count based on \a suggestion.
 
    In qtestcase.cpp, TestMethods::invokeTestOnData() invokes the test method in
    a loop until (the test fails or skips, or) the test run's duration exceeds a
    certain minimum; setResults() doubles \c iterationCount when it doesn't
    accept the result. In each call to the test method, the QBENCHMARK duly
    performs \c iteractionCount cycles of its block of code, from which other
    things make the above decisions about whether to double and try again.
*/
int QBenchmarkTestMethodData::initialIterationCount(int suggestion) const
{
    // Let the -iterations option override the measurer.
    if (QBenchmarkGlobalData::current->iterationCount != -1)
        return QBenchmarkGlobalData::current->iterationCount;
 
    return QBenchmarkGlobalData::current->measurer->adjustIterationCount(suggestion);
}
 
void QBenchmarkTestMethodData::setResults(const QList<QBenchmarkMeasurerBase::Measurement> &list,
                                          bool setByMacro)
{
    bool accepted = false;
    QBenchmarkMeasurerBase::Measurement firstMeasurement = {};
    if (!list.isEmpty())
        firstMeasurement = list.constFirst();
 
    // Always accept the result if the iteration count has been
    // specified on the command line with -iterations.
    if (QBenchmarkGlobalData::current->iterationCount != -1)
        accepted = true;
 
    else if (QBenchmarkTestMethodData::current->runOnce || !setByMacro) {
        iterationCount = 1;
        accepted = true;
    }
 
    // Test the result directly without calling the measurer if the minimum time
    // has been specified on the command line with -minimumvalue.
    else if (QBenchmarkGlobalData::current->walltimeMinimum != -1)
        accepted = (firstMeasurement.value > QBenchmarkGlobalData::current->walltimeMinimum);
    else
        accepted = QBenchmarkGlobalData::current->measurer->isMeasurementAccepted(firstMeasurement);
 
    QBenchmarkGlobalData::current->measurer->resetMetricsResults();
    // Accept the result or double the number of iterations.
    if (accepted)
        resultAccepted = true;
    else
        iterationCount *= 2;
 
    valid = true;
    results.reserve(list.size());
    for (auto m : list)
        results.emplaceBack(QBenchmarkGlobalData::current->context, m, iterationCount, setByMacro);
}
 
/*!
    \class QTest::QBenchmarkIterationController
    \internal
 
    The QBenchmarkIterationController class is used by the QBENCHMARK macro to
    drive the benchmarking loop. It is responsible for starting and stopping
    the timing measurements as well as calling the result reporting functions.
*/
 
/*! \internal
*/
QTest::QBenchmarkIterationController::QBenchmarkIterationController(RunMode runMode)
{
    i = 0;
    QBenchmarkTestMethodData::current->setBlockSize();
    if (runMode == RunOnce)
        QBenchmarkTestMethodData::current->runOnce = true;
    QTest::beginBenchmarkMeasurement();
}
 
QTest::QBenchmarkIterationController::QBenchmarkIterationController()
{
    i = 0;
    QBenchmarkTestMethodData::current->setBlockSize();
    QTest::beginBenchmarkMeasurement();
}
 
/*!
    \internal
    Split up iterations into a statistically useful number of blocks.
 
    Record data in blocks. \c split is the desired number of blocks which is a
    power of 2 like \c iterationcount. As long as split is below 32 we treat
    each iteration as a block. When split is greater than 32 \c split becomes
    a divisor for \c iterationcount. The goal is to reduce overhead from
    measurements while calculating variance. The default \c split 32 should be
    sufficient to get stable block-variance, from which the per-iteration
    variance (estimator) can be computed by dividing by the block size.
*/
void QBenchmarkTestMethodData::setBlockSize(int split)
{
    measurementBlockSize = iterationCount > split ? iterationCount / split : 1;
}
 
/*! \internal
*/
QTest::QBenchmarkIterationController::~QBenchmarkIterationController()
{
    QBenchmarkTestMethodData::current->setResults(QTest::endBenchmarkMeasurement());
}
 
/*! \internal
*/
bool QTest::QBenchmarkIterationController::isDone() const noexcept
{
    if (QBenchmarkTestMethodData::current->runOnce)
        return i > 0;
    return i >= QTest::iterationCount();
}
 
/*! \internal
*/
void QTest::QBenchmarkIterationController::next() noexcept
{
    ++i;
    // Record data once per block
    if (i % QBenchmarkTestMethodData::current->measurementBlockSize == 0)
        QBenchmarkGlobalData::current->measurer->updateMeasurement();
}
 
/*! \internal
*/
int QTest::iterationCount() noexcept
{
    return QBenchmarkTestMethodData::current->iterationCount;
}
 
/*! \internal
*/
void QTest::beginBenchmarkMeasurement()
{
    QBenchmarkGlobalData::current->measurer->start();
    // the clock is ticking after the line above, don't add code here.
}
 
/*! \internal
*/
QList<QBenchmarkMeasurerBase::Measurement> QTest::endBenchmarkMeasurement()
{
    // the clock is ticking before the line below, don't add code here.
    return QBenchmarkGlobalData::current->measurer->stop();
}
 
/*!
    Sets the benchmark result for this test function to \a result.
 
    Use this function if you want to report benchmark results without
    using the QBENCHMARK macro. Use \a metric to specify how Qt Test
    should interpret the results.
 
    The context for the result will be the test function name and any
    data tag from the _data function. This function can only be called
    once in each test function, subsequent calls will replace the
    earlier reported results.
 
    Note that the -iterations command line argument has no effect
    on test functions without the QBENCHMARK macro.
 
    \since 4.7
*/
void QTest::setBenchmarkResult(qreal result, QTest::QBenchmarkMetric metric)
{
    QBenchmarkTestMethodData::current->setResult({ result, 0, metric }, false);
}
 
QT_END_NAMESPACE