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Bug
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Resolution: Unresolved
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Not Evaluated
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None
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Qt Creator 10.0.0-beta2
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None
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Linux/X11
It looks like SubDirFileIterator is slower about 20 times comparing to QDir::entryInfoList() when done recursively in case many files / dirs are being iterated. I've set homePath to path where I have about 1.5 million files and about 200 K dirs. Modify this path accordingly when verifying the code below:
const QString homePath = QDir::homePath() + "/dev/";
qDebug() << homePath;
{
QElapsedTimer timer;
timer.start();
int dirCount = 0;
int count = 0;
const QDir home(homePath);
QFileInfoList workingList = home.entryInfoList(QDir::Dirs | QDir::Files | QDir::Hidden | QDir::NoDotAndDotDot);
while (!workingList.isEmpty()) {
const QFileInfo fi = workingList.takeLast();
if (fi.isDir()) {
++dirCount;
workingList.append(QDir(fi.filePath()).entryInfoList(QDir::Dirs | QDir::Files | QDir::Hidden | QDir::NoDotAndDotDot));
} else {
++count;
if (count % 100000 == 0)
qDebug() << count;
}
}
qDebug() << "EntryInfoList: Elapsed" << timer.elapsed() << "ms, count" << count << "dir count:" << dirCount;
}
{
QElapsedTimer timer;
timer.start();
int count = 0;
const FilePath home(FilePath::fromString(homePath));
SubDirFileIterator it({home}, {}, {});
auto i = it.begin();
const auto e = it.end();
while (i != e) {
++count;
++i;
if (count % 100000 == 0)
qDebug() << count;
}
qDebug() << "SubDirIterator: Elapsed" << timer.elapsed() << "ms, count" << count;
}
My output:
EntryInfoList: Elapsed 9795 ms, count 1437077 dir count: 196468 SubDirIterator: Elapsed 174612 ms, count 1436843
Side note: not sure why the number of files differ in both cases.
| For Gerrit Dashboard: QTCREATORBUG-28892 | ||||||
|---|---|---|---|---|---|---|
| # | Subject | Branch | Project | Status | CR | V |
| 476058,41 | SubDirFileIterator: Fix performance | master | qt-creator/qt-creator | Status: ABANDONED | +1 | 0 |
| 477649,25 | SubDirFileIterator: Add manual performance test | master | qt-creator/qt-creator | Status: MERGED | +2 | 0 |
| 479244,1 | SubDirFileIterator: Fix performance | 11.0 | qt-creator/qt-creator | Status: ABANDONED | 0 | 0 |
| 479392,31 | FileSearch: Introduce FileContainer | master | qt-creator/qt-creator | Status: MERGED | +2 | 0 |