1// Copyright (C) 2016 The Qt Company Ltd.
2// SPDX-License-Identifier: LicenseRef-Qt-Commercial OR GPL-3.0-only WITH Qt-GPL-exception-1.0
3
4#include "qmltime.h"
5
6#include <QQmlEngine>
7#include <QDebug>
8#include <QGuiApplication>
9#include <QElapsedTimer>
10#include <QQmlContext>
11#include <QQuickItem>
12
13#include <private/qquickview_p.h>
14
15Timer *Timer::m_timer = nullptr;
16
17Timer::Timer()
18 : m_component(nullptr)
19 , m_willparent(false)
20 , m_item(new QQuickItem)
21{
22 if (m_timer)
23 qWarning(msg: "Timer: Timer already registered");
24 QQuickViewPrivate::get(view: &m_view)->setRootObject(m_item);
25 m_timer = this;
26}
27
28QQmlComponent *Timer::component() const
29{
30 return m_component;
31}
32
33void Timer::setComponent(QQmlComponent *c)
34{
35 m_component = c;
36}
37
38Timer *Timer::timerInstance()
39{
40 return m_timer;
41}
42
43void Timer::run(uint iterations)
44{
45 QQmlContext context(qmlContext(this));
46
47 QObject *o = m_component->create(context: &context);
48 QQuickItem *i = qobject_cast<QQuickItem *>(o);
49 if (m_willparent && i)
50 i->setParentItem(m_item);
51 delete o;
52
53 runTest(&context, iterations);
54}
55
56bool Timer::willParent() const
57{
58 return m_willparent;
59}
60
61void Timer::setWillParent(bool p)
62{
63 m_willparent = p;
64}
65
66void Timer::runTest(QQmlContext *context, uint iterations)
67{
68 QElapsedTimer t;
69 t.start();
70 for (uint ii = 0; ii < iterations; ++ii) {
71 QObject *o = m_component->create(context);
72 QQuickItem *i = qobject_cast<QQuickItem *>(o);
73 if (m_willparent && i)
74 i->setParentItem(m_item);
75 delete o;
76 }
77
78 int e = t.elapsed();
79
80 qWarning() << "Total:" << e << "ms, Per iteration:" << qreal(e) / qreal(iterations) << "ms";
81
82}
83
84void usage(const char *name)
85{
86 qWarning(msg: "Usage: %s [-iterations <count>] [-parent] <qml file>\n", name);
87
88 qWarning(msg: "qmltime is a tool for benchmarking the runtime cost of instantiating\n"
89 "a QML component. It is typically run as follows:\n"
90 "\n"
91 "%s path/to/benchmark.qml\n"
92 "\n"
93 "If the -parent option is specified, the component being measured will also\n"
94 "be parented to an item already in the scene.\n"
95 "\n"
96 "If the -iterations option is specified, the benchmark will run the specified\n"
97 "number of iterations. If -iterations is not specified, 1024 iterations\n"
98 "are performed.\n"
99 "\n"
100 "qmltime expects the file to be benchmarked to contain a certain structure.\n"
101 "Specifically, it requires the presence of a QmlTime.Timer element. For example,\n"
102 "say we wanted to benchmark the following list delegate:\n"
103 "\n"
104 "Rectangle {\n"
105 " color: \"green\"\n"
106 " width: 400; height: 100\n"
107 " Text {\n"
108 " anchors.centerIn: parent\n"
109 " text: name\n"
110 " }\n"
111 "}\n"
112 "\n"
113 "we would create a benchmark file that looks like this:\n"
114 "\n"
115 "import QtQuick 2.0\n"
116 "import QmlTime 1.0 as QmlTime\n"
117 "\n"
118 "Item {\n"
119 "\n"
120 " property string name: \"Bob Smith\"\n"
121 "\n"
122 " QmlTime.Timer {\n"
123 " component: Rectangle {\n"
124 " color: \"green\"\n"
125 " width: 400; height: 100\n"
126 " Text {\n"
127 " anchors.centerIn: parent\n"
128 " text: name\n"
129 " }\n"
130 " }\n"
131 " }\n"
132 "}\n"
133 "\n"
134 "The outer Item functions as a dummy data provider for any additional\n"
135 "data required by the bindings in the component being benchmarked (in the\n"
136 "example above we provide a \"name\" property).\n"
137 "\n"
138 "When started, the component is instantiated once before running\n"
139 "the benchmark, which means that the reported time does not include\n"
140 "compile time (as the results of compilation are cached internally).\n"
141 "In this sense the times reported by qmltime best correspond to the\n"
142 "costs associated with delegate creation in the view classes, where the\n"
143 "same delegate is instantiated over and over. Conversely, it is not a\n"
144 "good approximation for e.g. Loader, which typically only instantiates\n"
145 "an element once (and so for Loader the compile time is very relevant\n"
146 "to the overall cost).", name);
147
148 exit(status: -1);
149}
150
151int main(int argc, char ** argv)
152{
153 QGuiApplication app(argc, argv);
154 QCoreApplication::setApplicationVersion(QLatin1String(QT_VERSION_STR));
155
156 uint iterations = 1024;
157 QString filename;
158 bool willParent = false;
159
160 for (int ii = 1; ii < argc; ++ii) {
161 QByteArray arg(argv[ii]);
162
163 if (arg == "-iterations") {
164 if (ii + 1 < argc) {
165 ++ii;
166 QByteArray its(argv[ii]);
167 bool ok = false;
168 iterations = its.toUInt(ok: &ok);
169 if (!ok || iterations == 0)
170 usage(name: argv[0]);
171 } else {
172 usage(name: argv[0]);
173 }
174 } else if (arg == "-parent") {
175 willParent = true;
176 } else if (arg == "-help") {
177 usage(name: argv[0]);
178 } else {
179 filename = QLatin1String(argv[ii]);
180 }
181 }
182
183 if (filename.isEmpty())
184 usage(name: argv[0]);
185
186 QQmlEngine engine;
187 QQmlComponent component(&engine, filename);
188 if (component.isError()) {
189 qWarning() << component.errors();
190 return -1;
191 }
192
193 QObject *obj = component.create();
194 if (!obj) {
195 qWarning() << component.errors();
196 return -1;
197 }
198
199 Timer *timer = Timer::timerInstance();
200 if (!timer) {
201 qWarning() << "A QmlTime.Timer instance is required.";
202 return -1;
203 }
204
205 timer->setWillParent(willParent);
206
207 if (!timer->component()) {
208 qWarning() << "The timer has no component";
209 return -1;
210 }
211
212 timer->run(iterations);
213
214 return 0;
215}
216

source code of qtdeclarative/tools/qmltime/qmltime.cpp