Fix QArrayDataOps generic and relocatable emplace()

Emplace() implemented with std::rotate is just awful on my system
(Ubuntu 18.04 GCC 7.5.0). Custom code is much faster, so go for
it. Cannot really use insert() code, which is also fast, because
it doesn't forward-reference values but copies them always

Changes in performance (approximately) for emplacing 100k elements
into the middle:
Complex 7600ms -> 1700ms
Movable 7600ms -> 200ms

Task-number: QTBUG-86583
Change-Id: If883c9b8498a89e757f3806aea11f8fd3aa3c709
Reviewed-by: Mårten Nordheim <marten.nordheim@qt.io>
Reviewed-by: Lars Knoll <lars.knoll@qt.io>
Reviewed-by: Thiago Macieira <thiago.macieira@intel.com>
This commit is contained in:
Andrei Golubev 2020-11-04 17:58:12 +01:00
parent 9ede51d214
commit 250b69ace4
3 changed files with 333 additions and 27 deletions

View File

@ -772,10 +772,31 @@ public:
Q_ASSERT(where >= this->begin() && where <= this->end());
Q_ASSERT(this->freeSpaceAtEnd() >= 1);
if (where == this->end()) {
createInPlace(this->end(), std::forward<Args>(args)...);
++this->size;
} else {
T tmp(std::forward<Args>(args)...);
std::rotate(where, this->end() - 1, this->end());
T *const end = this->end();
T *readIter = end - 1;
T *writeIter = end;
// Create new element at the end
new (writeIter) T(std::move(*readIter));
++this->size;
// Move assign over existing elements
while (readIter != where) {
--readIter;
--writeIter;
*writeIter = std::move(*readIter);
}
// Assign new element
--writeIter;
*writeIter = std::move(tmp);
}
}
template <typename iterator, typename ...Args>
@ -785,11 +806,35 @@ public:
Q_ASSERT(where >= this->begin() && where <= this->end());
Q_ASSERT(this->freeSpaceAtBegin() >= 1);
if (where == this->begin()) {
createInPlace(this->begin() - 1, std::forward<Args>(args)...);
--this->ptr;
++this->size;
} else {
T tmp(std::forward<Args>(args)...);
std::rotate(this->begin(), this->begin() + 1, where);
T *const begin = this->begin();
T *readIter = begin;
T *writeIter = begin - 1;
// Create new element at the beginning
new (writeIter) T(std::move(*readIter));
--this->ptr;
++this->size;
++readIter;
++writeIter;
// Move assign over existing elements
while (readIter != where) {
*writeIter = std::move(*readIter);
++readIter;
++writeIter;
}
// Assign new element
*writeIter = std::move(tmp);
}
}
void erase(T *b, T *e)
@ -998,6 +1043,54 @@ public:
// use moving insert
using QGenericArrayOps<T>::insert;
template<typename iterator, typename... Args>
void emplace(iterator where, Args &&... args)
{
emplace(GrowsForwardTag {}, where, std::forward<Args>(args)...);
}
template<typename iterator, typename... Args>
void emplace(GrowsForwardTag, iterator where, Args &&... args)
{
Q_ASSERT(!this->isShared());
Q_ASSERT(where >= this->begin() && where <= this->end());
Q_ASSERT(this->freeSpaceAtEnd() >= 1);
if (where == this->end()) {
this->createInPlace(where, std::forward<Args>(args)...);
} else {
T tmp(std::forward<Args>(args)...);
typedef typename QArrayExceptionSafetyPrimitives<T>::Displacer ReversibleDisplace;
ReversibleDisplace displace(where, this->end(), 1);
this->createInPlace(where, std::move(tmp));
displace.commit();
}
++this->size;
}
template<typename iterator, typename... Args>
void emplace(GrowsBackwardsTag, iterator where, Args &&... args)
{
Q_ASSERT(!this->isShared());
Q_ASSERT(where >= this->begin() && where <= this->end());
Q_ASSERT(this->freeSpaceAtBegin() >= 1);
if (where == this->begin()) {
this->createInPlace(where - 1, std::forward<Args>(args)...);
} else {
T tmp(std::forward<Args>(args)...);
typedef typename QArrayExceptionSafetyPrimitives<T>::Displacer ReversibleDisplace;
ReversibleDisplace displace(this->begin(), where, -1);
this->createInPlace(where - 1, std::move(tmp));
displace.commit();
}
--this->ptr;
++this->size;
}
// use moving emplace
using QGenericArrayOps<T>::emplace;
void erase(T *b, T *e)
{ erase(GrowsForwardTag{}, b, e); }

View File

@ -82,6 +82,8 @@ private slots:
void freeSpace();
void dataPointerAllocate_data();
void dataPointerAllocate();
void selfEmplaceBackwards();
void selfEmplaceForward();
#ifndef QT_NO_EXCEPTIONS
void exceptionSafetyPrimitives_constructor();
void exceptionSafetyPrimitives_destructor();
@ -2128,6 +2130,157 @@ void tst_QArrayData::dataPointerAllocate()
}
}
struct MyQStringWrapper : public QString
{
bool movedTo = false;
bool movedFrom = false;
MyQStringWrapper() = default;
MyQStringWrapper(QChar c) : QString(c) { }
MyQStringWrapper(MyQStringWrapper &&other) : QString(std::move(static_cast<QString>(other)))
{
movedTo = true;
movedFrom = other.movedFrom;
other.movedFrom = true;
}
MyQStringWrapper &operator=(MyQStringWrapper &&other)
{
QString::operator=(std::move(static_cast<QString>(other)));
movedTo = true;
movedFrom = other.movedFrom;
other.movedFrom = true;
return *this;
}
MyQStringWrapper(const MyQStringWrapper &) = default;
MyQStringWrapper &operator=(const MyQStringWrapper &) = default;
~MyQStringWrapper() = default;
};
struct MyMovableQString : public MyQStringWrapper
{
MyMovableQString() = default;
MyMovableQString(QChar c) : MyQStringWrapper(c) { }
private:
friend bool operator==(const MyMovableQString &a, QChar c)
{
return static_cast<QString>(a) == QString(c);
}
friend bool operator==(const MyMovableQString &a, const MyMovableQString &b)
{
return static_cast<QString>(a) == static_cast<QString>(b);
}
};
QT_BEGIN_NAMESPACE
Q_DECLARE_TYPEINFO(MyMovableQString, Q_RELOCATABLE_TYPE);
QT_END_NAMESPACE
static_assert(QTypeInfo<MyMovableQString>::isComplex);
static_assert(QTypeInfo<MyMovableQString>::isRelocatable);
struct MyComplexQString : public MyQStringWrapper
{
MyComplexQString() = default;
MyComplexQString(QChar c) : MyQStringWrapper(c) { }
private:
friend bool operator==(const MyComplexQString &a, QChar c)
{
return static_cast<QString>(a) == QString(c);
}
friend bool operator==(const MyComplexQString &a, const MyComplexQString &b)
{
return static_cast<QString>(a) == static_cast<QString>(b);
}
};
static_assert(QTypeInfo<MyComplexQString>::isComplex);
static_assert(!QTypeInfo<MyComplexQString>::isRelocatable);
void tst_QArrayData::selfEmplaceBackwards()
{
const auto createDataPointer = [](qsizetype capacity, int spaceAtEnd, auto dummy) {
using Type = std::decay_t<decltype(dummy)>;
Q_UNUSED(dummy);
auto [header, ptr] = QTypedArrayData<Type>::allocate(capacity, QArrayData::Grow);
// do custom adjustments to make sure there's free space at end
ptr += header->alloc - spaceAtEnd;
return QArrayDataPointer(header, ptr);
};
const auto testSelfEmplace = [&](auto dummy, int spaceAtEnd, auto initValues) {
auto adp = createDataPointer(100, spaceAtEnd, dummy);
for (auto v : initValues) {
adp->emplaceBack(v);
}
QVERIFY(!adp.freeSpaceAtEnd());
QVERIFY(adp.freeSpaceAtBegin());
adp->emplace(adp.end(), adp.data()[0]);
for (qsizetype i = 0; i < adp.size - 1; ++i) {
QCOMPARE(adp.data()[i], initValues[i]);
}
QCOMPARE(adp.data()[adp.size - 1], initValues[0]);
adp->emplace(adp.end(), std::move(adp.data()[0]));
for (qsizetype i = 1; i < adp.size - 2; ++i) {
QCOMPARE(adp.data()[i], initValues[i]);
}
QCOMPARE(adp.data()[adp.size - 2], initValues[0]);
QCOMPARE(adp.data()[0].movedFrom, true);
QCOMPARE(adp.data()[adp.size - 1], initValues[0]);
QCOMPARE(adp.data()[adp.size - 1].movedTo, true);
};
QList<QChar> movableObjs { u'a', u'b', u'c', u'd' };
RUN_TEST_FUNC(testSelfEmplace, MyMovableQString(), 4, movableObjs);
QList<QChar> complexObjs { u'a', u'b', u'c', u'd' };
RUN_TEST_FUNC(testSelfEmplace, MyComplexQString(), 4, complexObjs);
}
void tst_QArrayData::selfEmplaceForward()
{
const auto createDataPointer = [](qsizetype capacity, int spaceAtBegin, auto dummy) {
using Type = std::decay_t<decltype(dummy)>;
Q_UNUSED(dummy);
auto [header, ptr] = QTypedArrayData<Type>::allocate(capacity, QArrayData::Grow);
// do custom adjustments to make sure there's free space at end
ptr += spaceAtBegin;
return QArrayDataPointer(header, ptr);
};
const auto testSelfEmplace = [&](auto dummy, int spaceAtBegin, auto initValues) {
auto adp = createDataPointer(100, spaceAtBegin, dummy);
auto reversedInitValues = initValues;
std::reverse(reversedInitValues.begin(), reversedInitValues.end());
for (auto v : reversedInitValues) {
adp->emplaceFront(v);
}
QVERIFY(!adp.freeSpaceAtBegin());
QVERIFY(adp.freeSpaceAtEnd());
adp->emplace(adp.begin(), adp.data()[adp.size - 1]);
for (qsizetype i = 1; i < adp.size; ++i) {
QCOMPARE(adp.data()[i], initValues[i - 1]);
}
QCOMPARE(adp.data()[0], initValues[spaceAtBegin - 1]);
adp->emplace(adp.begin(), std::move(adp.data()[adp.size - 1]));
for (qsizetype i = 2; i < adp.size; ++i) {
QCOMPARE(adp.data()[i], initValues[i - 2]);
}
QCOMPARE(adp.data()[1], initValues[spaceAtBegin - 1]);
QCOMPARE(adp.data()[adp.size - 1].movedFrom, true);
QCOMPARE(adp.data()[0], initValues[spaceAtBegin - 1]);
QCOMPARE(adp.data()[0].movedTo, true);
};
QList<QChar> movableObjs { u'a', u'b', u'c', u'd' };
RUN_TEST_FUNC(testSelfEmplace, MyMovableQString(), 4, movableObjs);
QList<QChar> complexObjs { u'a', u'b', u'c', u'd' };
RUN_TEST_FUNC(testSelfEmplace, MyComplexQString(), 4, complexObjs);
}
#ifndef QT_NO_EXCEPTIONS
struct ThrowingTypeWatcher
{

View File

@ -184,11 +184,11 @@ private Q_SLOTS:
void appendPrependOne_complex_data() const { commonBenchmark_data<MyComplex>(); }
void appendPrependOne_QString_data() const { commonBenchmark_data<QString>(); }
void appendPrependOne_int() const { midInsertOne_impl<QList, int>(); }
void appendPrependOne_primitive() const { midInsertOne_impl<QList, MyPrimitive>(); }
void appendPrependOne_movable() const { midInsertOne_impl<QList, MyMovable>(); }
void appendPrependOne_complex() const { midInsertOne_impl<QList, MyComplex>(); }
void appendPrependOne_QString() const { midInsertOne_impl<QList, QString>(); }
void appendPrependOne_int() const { appendPrependOne_impl<QList, int>(); }
void appendPrependOne_primitive() const { appendPrependOne_impl<QList, MyPrimitive>(); }
void appendPrependOne_movable() const { appendPrependOne_impl<QList, MyMovable>(); }
void appendPrependOne_complex() const { appendPrependOne_impl<QList, MyComplex>(); }
void appendPrependOne_QString() const { appendPrependOne_impl<QList, QString>(); }
// prepend half elements, then appen another half:
void prependAppendHalvesOne_int_data() const { commonBenchmark_data<int>(); }
@ -197,11 +197,27 @@ private Q_SLOTS:
void prependAppendHalvesOne_complex_data() const { commonBenchmark_data<MyComplex>(); }
void prependAppendHalvesOne_QString_data() const { commonBenchmark_data<QString>(); }
void prependAppendHalvesOne_int() const { midInsertOne_impl<QList, int>(); }
void prependAppendHalvesOne_primitive() const { midInsertOne_impl<QList, MyPrimitive>(); }
void prependAppendHalvesOne_movable() const { midInsertOne_impl<QList, MyMovable>(); }
void prependAppendHalvesOne_complex() const { midInsertOne_impl<QList, MyComplex>(); }
void prependAppendHalvesOne_QString() const { midInsertOne_impl<QList, QString>(); }
void prependAppendHalvesOne_int() const { prependAppendHalvesOne_impl<QList, int>(); }
void prependAppendHalvesOne_primitive() const
{
prependAppendHalvesOne_impl<QList, MyPrimitive>();
}
void prependAppendHalvesOne_movable() const { prependAppendHalvesOne_impl<QList, MyMovable>(); }
void prependAppendHalvesOne_complex() const { prependAppendHalvesOne_impl<QList, MyComplex>(); }
void prependAppendHalvesOne_QString() const { prependAppendHalvesOne_impl<QList, QString>(); }
// emplace in middle 1 element:
void midEmplaceOne_int_data() const { commonBenchmark_data<int>(); }
void midEmplaceOne_primitive_data() const { commonBenchmark_data<MyPrimitive>(); }
void midEmplaceOne_movable_data() const { commonBenchmark_data<MyMovable>(); }
void midEmplaceOne_complex_data() const { commonBenchmark_data<MyComplex>(); }
void midEmplaceOne_QString_data() const { commonBenchmark_data<QString>(); }
void midEmplaceOne_int() const { midEmplaceOne_impl<QList, int>(); }
void midEmplaceOne_primitive() const { midEmplaceOne_impl<QList, MyPrimitive>(); }
void midEmplaceOne_movable() const { midEmplaceOne_impl<QList, MyMovable>(); }
void midEmplaceOne_complex() const { midEmplaceOne_impl<QList, MyComplex>(); }
void midEmplaceOne_QString() const { midEmplaceOne_impl<QList, QString>(); }
// For 5.15 we also want to compare against QVector
#if QT_VERSION < QT_VERSION_CHECK(6, 0, 0)
@ -251,11 +267,14 @@ private Q_SLOTS:
void qvector_appendPrependOne_complex_data() const { commonBenchmark_data<MyComplex>(); }
void qvector_appendPrependOne_QString_data() const { commonBenchmark_data<QString>(); }
void qvector_appendPrependOne_int() const { midInsertOne_impl<QVector, int>(); }
void qvector_appendPrependOne_primitive() const { midInsertOne_impl<QVector, MyPrimitive>(); }
void qvector_appendPrependOne_movable() const { midInsertOne_impl<QVector, MyMovable>(); }
void qvector_appendPrependOne_complex() const { midInsertOne_impl<QVector, MyComplex>(); }
void qvector_appendPrependOne_QString() const { midInsertOne_impl<QVector, QString>(); }
void qvector_appendPrependOne_int() const { appendPrependOne_impl<QVector, int>(); }
void qvector_appendPrependOne_primitive() const
{
appendPrependOne_impl<QVector, MyPrimitive>();
}
void qvector_appendPrependOne_movable() const { appendPrependOne_impl<QVector, MyMovable>(); }
void qvector_appendPrependOne_complex() const { appendPrependOne_impl<QVector, MyComplex>(); }
void qvector_appendPrependOne_QString() const { appendPrependOne_impl<QVector, QString>(); }
// prepend half elements, then appen another half:
void qvector_prependAppendHalvesOne_int_data() const { commonBenchmark_data<int>(); }
@ -267,14 +286,36 @@ private Q_SLOTS:
void qvector_prependAppendHalvesOne_complex_data() const { commonBenchmark_data<MyComplex>(); }
void qvector_prependAppendHalvesOne_QString_data() const { commonBenchmark_data<QString>(); }
void qvector_prependAppendHalvesOne_int() const { midInsertOne_impl<QVector, int>(); }
void qvector_prependAppendHalvesOne_int() const { prependAppendHalvesOne_impl<QVector, int>(); }
void qvector_prependAppendHalvesOne_primitive() const
{
midInsertOne_impl<QVector, MyPrimitive>();
prependAppendHalvesOne_impl<QVector, MyPrimitive>();
}
void qvector_prependAppendHalvesOne_movable() const { midInsertOne_impl<QVector, MyMovable>(); }
void qvector_prependAppendHalvesOne_complex() const { midInsertOne_impl<QVector, MyComplex>(); }
void qvector_prependAppendHalvesOne_QString() const { midInsertOne_impl<QVector, QString>(); }
void qvector_prependAppendHalvesOne_movable() const
{
prependAppendHalvesOne_impl<QVector, MyMovable>();
}
void qvector_prependAppendHalvesOne_complex() const
{
prependAppendHalvesOne_impl<QVector, MyComplex>();
}
void qvector_prependAppendHalvesOne_QString() const
{
prependAppendHalvesOne_impl<QVector, QString>();
}
// emplace in middle 1 element:
void qvector_midEmplaceOne_int_data() const { commonBenchmark_data<int>(); }
void qvector_midEmplaceOne_primitive_data() const { commonBenchmark_data<MyPrimitive>(); }
void qvector_midEmplaceOne_movable_data() const { commonBenchmark_data<MyMovable>(); }
void qvector_midEmplaceOne_complex_data() const { commonBenchmark_data<MyComplex>(); }
void qvector_midEmplaceOne_QString_data() const { commonBenchmark_data<QString>(); }
void qvector_midEmplaceOne_int() const { midEmplaceOne_impl<QVector, int>(); }
void qvector_midEmplaceOne_primitive() const { midEmplaceOne_impl<QVector, MyPrimitive>(); }
void qvector_midEmplaceOne_movable() const { midEmplaceOne_impl<QVector, MyMovable>(); }
void qvector_midEmplaceOne_complex() const { midEmplaceOne_impl<QVector, MyComplex>(); }
void qvector_midEmplaceOne_QString() const { midEmplaceOne_impl<QVector, QString>(); }
#endif
private:
@ -295,6 +336,9 @@ private:
template<template<typename> typename, typename>
void prependAppendHalvesOne_impl() const;
template<template<typename> typename, typename>
void midEmplaceOne_impl() const;
};
template <class T>
@ -495,6 +539,22 @@ void tst_QList::prependAppendHalvesOne_impl() const
}
}
template<template<typename> typename Container, typename T>
void tst_QList::midEmplaceOne_impl() const
{
QFETCH(int, elemCount);
constexpr auto getValue = []() { return T {}; };
QBENCHMARK {
Container<T> container;
auto lvalue = getValue();
for (int i = 0; i < elemCount; ++i) {
container.emplace(container.size() / 2, lvalue);
}
}
}
QTEST_APPLESS_MAIN(tst_QList)
#include "main.moc"