qt5base-lts/src/testlib/qbenchmark.cpp
Mirko Boehm (AWS) 1a708277c5 Add minimumtotal option to improve accuracy of short-lived benchmarks.
Short-lived benchmarks (benchmarks that complete in a very short period
of measured time) are often more affected by jitter and warm-up effects
than longer running benchmarks. Since QBENCHMARK stores the median
result of all accepted benchmark runs, a larger number of aggregation
runs is preferable for short-lived tests, but not necessarily for longer
running ones. The minimumtotal option, specified in units of the
selected measurement, will make the benchmark repeat a benchmark until
the total measured cost exceeds the specified threshold. The displayed
median result will then tend to be more accurate. This is especially
useful for data-driven benchmarks in case the data tags scale the
benchmarked operation from little to large cost.

Change-Id: Ib857de64aaffc77715a0000d36f0245f31d86b9a
Reviewed-by: Jason McDonald <macadder1@gmail.com>
2013-03-19 10:29:23 +01:00

308 lines
8.7 KiB
C++

/****************************************************************************
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#include <QtTest/qbenchmark.h>
#include <QtTest/private/qbenchmark_p.h>
#include <QtTest/private/qbenchmarkmetric_p.h>
#include <QtCore/qprocess.h>
#include <QtCore/qdir.h>
#include <QtCore/qset.h>
#include <QtCore/qdebug.h>
QT_BEGIN_NAMESPACE
QBenchmarkGlobalData *QBenchmarkGlobalData::current;
QBenchmarkGlobalData::QBenchmarkGlobalData()
: measurer(0)
, walltimeMinimum(-1)
, iterationCount(-1)
, medianIterationCount(-1)
, createChart(false)
, verboseOutput(false)
, minimumTotal(-1)
, mode_(WallTime)
{
setMode(mode_);
}
QBenchmarkGlobalData::~QBenchmarkGlobalData()
{
delete measurer;
QBenchmarkGlobalData::current = 0;
}
void QBenchmarkGlobalData::setMode(Mode mode)
{
mode_ = mode;
if (measurer)
delete measurer;
measurer = createMeasurer();
}
QBenchmarkMeasurerBase * QBenchmarkGlobalData::createMeasurer()
{
QBenchmarkMeasurerBase *measurer = 0;
if (0) {
#ifdef QTESTLIB_USE_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;
}
measurer->init();
return measurer;
}
int QBenchmarkGlobalData::adjustMedianIterationCount()
{
if (medianIterationCount != -1) {
return medianIterationCount;
} else {
return measurer->adjustMedianCount(1);
}
}
QBenchmarkTestMethodData *QBenchmarkTestMethodData::current;
QBenchmarkTestMethodData::QBenchmarkTestMethodData()
:resultAccepted(false), runOnce(false), iterationCount(-1)
{
}
QBenchmarkTestMethodData::~QBenchmarkTestMethodData()
{
QBenchmarkTestMethodData::current = 0;
}
void QBenchmarkTestMethodData::beginDataRun()
{
iterationCount = adjustIterationCount(1);
}
void QBenchmarkTestMethodData::endDataRun()
{
}
int QBenchmarkTestMethodData::adjustIterationCount(int suggestion)
{
// Let the -iterations option override the measurer.
if (QBenchmarkGlobalData::current->iterationCount != -1) {
iterationCount = QBenchmarkGlobalData::current->iterationCount;
} else {
iterationCount = QBenchmarkGlobalData::current->measurer->adjustIterationCount(suggestion);
}
return iterationCount;
}
void QBenchmarkTestMethodData::setResult(
qreal value, QTest::QBenchmarkMetric metric, bool setByMacro)
{
bool accepted = false;
// 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 = (value > QBenchmarkGlobalData::current->walltimeMinimum);
else
accepted = QBenchmarkGlobalData::current->measurer->isMeasurementAccepted(value);
// Accept the result or double the number of iterations.
if (accepted)
resultAccepted = true;
else
iterationCount *= 2;
this->result = QBenchmarkResult(
QBenchmarkGlobalData::current->context, value, iterationCount, metric, setByMacro);
}
/*!
\class QTest::QBenchmarkIterationController
\internal
The QBenchmarkIterationController class is used by the QBENCHMARK macro to
drive the benchmarking loop. It is repsonsible for starting and stopping
the timing measurements as well as calling the result reporting functions.
*/
/*! \internal
*/
QTest::QBenchmarkIterationController::QBenchmarkIterationController(RunMode runMode)
{
i = 0;
if (runMode == RunOnce)
QBenchmarkTestMethodData::current->runOnce = true;
QTest::beginBenchmarkMeasurement();
}
QTest::QBenchmarkIterationController::QBenchmarkIterationController()
{
i = 0;
QTest::beginBenchmarkMeasurement();
}
/*! \internal
*/
QTest::QBenchmarkIterationController::~QBenchmarkIterationController()
{
const qreal result = QTest::endBenchmarkMeasurement();
QBenchmarkTestMethodData::current->setResult(result, QBenchmarkGlobalData::current->measurer->metricType());
}
/*! \internal
*/
bool QTest::QBenchmarkIterationController::isDone()
{
if (QBenchmarkTestMethodData::current->runOnce)
return i > 0;
return i >= QTest::iterationCount();
}
/*! \internal
*/
void QTest::QBenchmarkIterationController::next()
{
++i;
}
/*! \internal
*/
int QTest::iterationCount()
{
return QBenchmarkTestMethodData::current->iterationCount;
}
/*! \internal
*/
void QTest::setIterationCountHint(int count)
{
QBenchmarkTestMethodData::current->adjustIterationCount(count);
}
/*! \internal
*/
void QTest::setIterationCount(int count)
{
QBenchmarkTestMethodData::current->iterationCount = count;
QBenchmarkTestMethodData::current->resultAccepted = true;
}
/*! \internal
*/
void QTest::beginBenchmarkMeasurement()
{
QBenchmarkGlobalData::current->measurer->start();
// the clock is ticking after the line above, don't add code here.
}
/*! \internal
*/
quint64 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, metric, false);
}
template <typename T>
typename T::value_type qAverage(const T &container)
{
typename T::const_iterator it = container.constBegin();
typename T::const_iterator end = container.constEnd();
typename T::value_type acc = typename T::value_type();
int count = 0;
while (it != end) {
acc += *it;
++it;
++count;
}
return acc / count;
}
QT_END_NAMESPACE