QReadWriteLock is supposed to be a better alternative to QMutex when there
are only a few writers but potentially lots of reads. However, in practice
the previous implementation was much slower, unless you really do a lot of
work with the lock for read and you have lots of contention.
Indeed, the previous implementation was locking a QMutex both for lock, and
unlock (making it already at least twice as slow as QMutex).
This new implementation brings QReadWriteLock back to the same level as QMutex:
- No memory allocations in the uncontended case (almost no overhead allowing to
create many of them in classes)
- Lock-free if there is no contention
Should support up to 2^31 concurrent readers on 64 bit platforms, and 2^28
on 32 bit platforms
Change-Id: Ifa2fc999075cbb971088f4ee8e6fde78ce262da3
Reviewed-by: Edward Welbourne <edward.welbourne@theqtcompany.com>
Reviewed-by: Sean Harmer <sean.harmer@kdab.com>
Reviewed-by: Robin Burchell <robin.burchell@viroteck.net>
I wrote a script to help find the files, but I reviewed the
contributions manually to be sure I wasn't claiming copyright for search
& replace, adding Q_DECL_NOTHROW or adding "We mean it" headers.
Change-Id: I7a9e11d7b64a4cc78e24ffff142b506368fc8842
Reviewed-by: Lars Knoll <lars.knoll@theqtcompany.com>
From Qt 5.7 -> LGPL v2.1 isn't an option anymore, see
http://blog.qt.io/blog/2016/01/13/new-agreement-with-the-kde-free-qt-foundation/
Updated license headers to use new LGPL header instead of LGPL21 one
(in those files which will be under LGPL v3)
Change-Id: I046ec3e47b1876cd7b4b0353a576b352e3a946d9
Reviewed-by: Lars Knoll <lars.knoll@theqtcompany.com>
The latest version of Haiku provides the implementation
for pthread_condattr_setclock, so we can enable the code
in QWaitCondition again to make it use the monotonic clock
correctly.
Change-Id: Ibb9ad33d873c3b34f2c516087c4e0aeac04cc83f
Reviewed-by: Augustin Cavalier <waddlesplash@gmail.com>
Reviewed-by: Thiago Macieira <thiago.macieira@intel.com>
wait() was always returning immediately, regardless of the timeout
value, due to a timespec comparison from different clock types.
On Android 5.0, qt_gettime() uses the monotonic clock but the wait
condition was using the real time clock.
__pthread_cond_timedwait_relative() is not exported anymore in
Android 5.0, we therefore fall back to pthread_cond_timedwait().
Since the monotonic clock is now available, qt_gettime returns
a time based on it. The wait condition consequently needs
to use the monotonic clock.
Change-Id: Ie7cf909b81107edd7207c3c039b3ec1f5422303f
Reviewed-by: Thiago Macieira <thiago.macieira@intel.com>
Reviewed-by: Eskil Abrahamsen Blomfeldt <eskil.abrahamsen-blomfeldt@theqtcompany.com>
Qt copyrights are now in The Qt Company, so we could update the source
code headers accordingly. In the same go we should also fix the links to
point to qt.io.
Outdated header.LGPL removed (use header.LGPL21 instead)
Old header.LGPL3 renamed to header.LGPL3-COMM to match actual licensing
combination. New header.LGPL-COMM taken in the use file which were
using old header.LGPL3 (src/plugins/platforms/android/extract.cpp)
Added new header.LGPL3 containing Commercial + LGPLv3 + GPLv2 license
combination
Change-Id: I6f49b819a8a20cc4f88b794a8f6726d975e8ffbe
Reviewed-by: Matti Paaso <matti.paaso@theqtcompany.com>
The Linux futex interface uses relative timeouts anyway, so this avoids
a double round-trip through clock_gettime: once in Qt code to calculate
absolute from relative and once in libc for reversing.
Glibc does not offer such a function because its pthread_cond objects
use a kernel interface that works on absolute times.
Change-Id: I8fbcd3f73d4364a16716b0eea17e8f5f9ab5cd05
Reviewed-by: Eskil Abrahamsen Blomfeldt <eskil.abrahamsen-blomfeldt@digia.com>
Reviewed-by: Thiago Macieira <thiago.macieira@intel.com>
Even if the monotonic clock is available, Android's Bionic lacks the
pthread_condattr_setclock function, so we can't tell it to use the
monotonic clock.
Task-number: QTBUG-30450
Change-Id: I4f53708b1e834ff5d9462b3bf778b96c22662a04
Reviewed-by: Eskil Abrahamsen Blomfeldt <eskil.abrahamsen-blomfeldt@digia.com>
Reviewed-by: Paul Olav Tvete <paul.tvete@digia.com>
Make them use the monotonic clock if that's available. On Mac, the
monotonic clock is not available -- Qt fakes monotonic support by using
the Mach timebase -- so we need to use gettimeofday.
Change-Id: Iaea0b0c0de1b4802780e2476dc3643b703db392c
Reviewed-by: Olivier Goffart <ogoffart@woboq.com>
Change copyrights and license headers from Nokia to Digia
Change-Id: If1cc974286d29fd01ec6c19dd4719a67f4c3f00e
Reviewed-by: Lars Knoll <lars.knoll@digia.com>
Reviewed-by: Sergio Ahumada <sergio.ahumada@digia.com>
As in the past, to avoid rewriting various autotests that contain
line-number information, an extra blank line has been inserted at the
end of the license text to ensure that this commit does not change the
total number of lines in the license header.
Change-Id: I311e001373776812699d6efc045b5f742890c689
Reviewed-by: Rohan McGovern <rohan.mcgovern@nokia.com>
And added a POD QBasicMutex. (QBasicMutex* can safely be
static_cast'ed to QMutex*)
The d pointer is not anymore always a QMutexPrivate.
If d == 0x0: the mutex is unlocked
If d == 0x1: the mutex is locked, uncontended
On linux:
if d == 0x3: the mutex is locked contended, waiting on a futex
If d is a pointer, it is a recursive mutex.
On non-linux platforms:
When a thread tries to lock a mutex for which d == 0x1, it will try to
assing it a QMutexPrivated (allocated from a freelist) in order to wait
for it.
Change-Id: Ie1431cd9402a576fdd9a693cfd747166eebf5622
Reviewed-by: Bradley T. Hughes <bradley.hughes@nokia.com>
Reviewed-on: http://codereview.qt.nokia.com/2116
Reviewed-by: Qt Sanity Bot <qt_sanity_bot@ovi.com>
Reviewed-by: Olivier Goffart <olivier.goffart@nokia.com>
This is the beginning of revision history for this module. If you
want to look at revision history older than this, please refer to the
Qt Git wiki for how to use Git history grafting. At the time of
writing, this wiki is located here:
http://qt.gitorious.org/qt/pages/GitIntroductionWithQt
If you have already performed the grafting and you don't see any
history beyond this commit, try running "git log" with the "--follow"
argument.
Branched from the monolithic repo, Qt master branch, at commit
896db169ea224deb96c59ce8af800d019de63f12
Olivier Goffart
Thiago Macieira
Jani Heikkinen
Tobias Koenig
Frederik Gladhorn
Yoann Lopes
Matti Paaso
David Faure
Sergio Ahumada
Iikka Eklund
Jason McDonald
Olivier Goffart
Jyri Tahtela
Qt by Nokia