From 31c6d9f04ba80e6776ae01cb0588e6bd228f7184 Mon Sep 17 00:00:00 2001 From: David Faure Date: Sun, 7 Sep 2014 01:18:22 +0200 Subject: QTextStream: add fast path for writing char and QChar. Avoids allocating a QString for every char being written out. The benchmark went from 5.5 ms per iteration to 0.8 ms, and from 40 million instructions to 6 million. Found using Milian Wolff's heaptrack tool. Change-Id: I1784c47b944454bc947a607a22c39d249372ed55 Reviewed-by: Adam Majer Reviewed-by: Marc Mutz --- tests/benchmarks/corelib/io/io.pro | 3 +- tests/benchmarks/corelib/io/qtextstream/main.cpp | 133 +++++++++++++++++++++ .../corelib/io/qtextstream/qtextstream.pro | 9 ++ 3 files changed, 144 insertions(+), 1 deletion(-) create mode 100644 tests/benchmarks/corelib/io/qtextstream/main.cpp create mode 100644 tests/benchmarks/corelib/io/qtextstream/qtextstream.pro (limited to 'tests/benchmarks/corelib') diff --git a/tests/benchmarks/corelib/io/io.pro b/tests/benchmarks/corelib/io/io.pro index 487171ac5e..38a1f6b15b 100644 --- a/tests/benchmarks/corelib/io/io.pro +++ b/tests/benchmarks/corelib/io/io.pro @@ -6,5 +6,6 @@ SUBDIRS = \ qfileinfo \ qiodevice \ qprocess \ - qtemporaryfile + qtemporaryfile \ + qtextstream diff --git a/tests/benchmarks/corelib/io/qtextstream/main.cpp b/tests/benchmarks/corelib/io/qtextstream/main.cpp new file mode 100644 index 0000000000..45c0297516 --- /dev/null +++ b/tests/benchmarks/corelib/io/qtextstream/main.cpp @@ -0,0 +1,133 @@ +/**************************************************************************** +** +** Copyright (C) 2014 David Faure +** Contact: http://www.qt-project.org/legal +** +** This file is part of the test suite of the Qt Toolkit. +** +** $QT_BEGIN_LICENSE:LGPL$ +** Commercial License Usage +** Licensees holding valid commercial Qt licenses may use this file in +** accordance with the commercial license agreement provided with the +** Software or, alternatively, in accordance with the terms contained in +** a written agreement between you and Digia. For licensing terms and +** conditions see http://qt.digia.com/licensing. For further information +** use the contact form at http://qt.digia.com/contact-us. +** +** 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, Digia gives you certain additional +** rights. These rights are described in the Digia Qt LGPL Exception +** version 1.1, 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. +** +** +** $QT_END_LICENSE$ +** +****************************************************************************/ + +#include +#include +#include +#include +#include + +class tst_qtextstream : public QObject +{ + Q_OBJECT +private slots: + void writeSingleChar_data(); + void writeSingleChar(); + +private: +}; + +enum Output { StringOutput, DeviceOutput }; +Q_DECLARE_METATYPE(Output); + +enum Input { CharStarInput, QStringInput, CharInput, QCharInput }; +Q_DECLARE_METATYPE(Input); + +void tst_qtextstream::writeSingleChar_data() +{ + QTest::addColumn("output"); + QTest::addColumn("input"); + + QTest::newRow("string_charstar") << StringOutput << CharStarInput; + QTest::newRow("string_string") << StringOutput << QStringInput; + QTest::newRow("string_char") << StringOutput << CharInput; + QTest::newRow("string_qchar") << StringOutput << QCharInput; + QTest::newRow("device_charstar") << DeviceOutput << CharStarInput; + QTest::newRow("device_string") << DeviceOutput << QStringInput; + QTest::newRow("device_char") << DeviceOutput << CharInput; + QTest::newRow("device_qchar") << DeviceOutput << QCharInput; +} + +void tst_qtextstream::writeSingleChar() +{ + QFETCH(Output, output); + QFETCH(Input, input); + + QString str; + QBuffer buffer; + QTextStream stream; + if (output == StringOutput) { + stream.setString(&str, QIODevice::WriteOnly); + } else { + QVERIFY(buffer.open(QIODevice::WriteOnly)); + stream.setDevice(&buffer); + } + // Test many different ways to write a single char into a QTextStream + QString inputString = "h"; + const int amount = 100000; + switch (input) { + case CharStarInput: + QBENCHMARK { + for (qint64 i = 0; i < amount; ++i) + stream << "h"; + } + break; + case QStringInput: + QBENCHMARK { + for (qint64 i = 0; i < amount; ++i) + stream << inputString; + } + break; + case CharInput: + QBENCHMARK { + for (qint64 i = 0; i < amount; ++i) + stream << 'h'; + } + break; + case QCharInput: + QBENCHMARK { + for (qint64 i = 0; i < amount; ++i) + stream << QChar('h'); + } + break; + } + QString result; + if (output == StringOutput) + result = str; + else + result = QString(buffer.data()); + + QCOMPARE(result.left(10), QString("hhhhhhhhhh")); +} + +QTEST_MAIN(tst_qtextstream) + +#include "main.moc" diff --git a/tests/benchmarks/corelib/io/qtextstream/qtextstream.pro b/tests/benchmarks/corelib/io/qtextstream/qtextstream.pro new file mode 100644 index 0000000000..3dcba655f2 --- /dev/null +++ b/tests/benchmarks/corelib/io/qtextstream/qtextstream.pro @@ -0,0 +1,9 @@ +TEMPLATE = app +TARGET = tst_bench_qtemporaryfile + +QT = core testlib + +CONFIG += release + +SOURCES += main.cpp +DEFINES += QT_DISABLE_DEPRECATED_BEFORE=0 -- cgit v1.2.3