diff options
| author | Thiago Macieira <thiago.macieira@intel.com> | 2012-08-11 16:03:51 +0200 |
|---|---|---|
| committer | Qt by Nokia <qt-info@nokia.com> | 2012-09-14 03:45:50 +0200 |
| commit | f587e8f4fd670f11fa1e878c1015d7241033559a (patch) | |
| tree | 8463cbfeffe6c7d678ad26d4be573cf739a39855 /src/corelib | |
| parent | d8eb52fc45d0209a07b07be2c0f54a9167704574 (diff) | |
Avoid calling QElapsedTimer::nsecsElapsed before the first futex sleep
The first time we're going to sleep, the timeout should be exactly the
value that was passed by the user. We don't need to calculate the time
elapsed between start() and a few lines below.
Change-Id: I99c363b6f0ecfd07ad787b79b75e61771733c2b3
Reviewed-by: Lars Knoll <lars.knoll@nokia.com>
Reviewed-by: Olivier Goffart <ogoffart@woboq.com>
Diffstat (limited to 'src/corelib')
| -rw-r--r-- | src/corelib/thread/qmutex_linux.cpp | 12 |
1 files changed, 8 insertions, 4 deletions
diff --git a/src/corelib/thread/qmutex_linux.cpp b/src/corelib/thread/qmutex_linux.cpp index 0c44d18b8f..e2842a670b 100644 --- a/src/corelib/thread/qmutex_linux.cpp +++ b/src/corelib/thread/qmutex_linux.cpp @@ -184,15 +184,18 @@ bool lockInternal_helper(QBasicAtomicPointer<QMutexData> &d_ptr, int timeout = - if (timeout == 0) return false; + struct timespec ts, *pts = 0; QElapsedTimer elapsedTimer; checkElapsedTimerIsTrivial(); - if (IsTimed) + if (IsTimed) { + ts.tv_sec = timeout / Q_INT64_C(1000) / 1000 / 1000; + ts.tv_nsec = timeout % Q_INT64_C(1000) * 1000 * 1000; elapsedTimer.start(); + } // the mutex is locked already, set a bit indicating we're waiting while (d_ptr.fetchAndStoreAcquire(dummyFutexValue()) != 0) { - struct timespec ts, *pts = 0; - if (IsTimed) { + if (IsTimed && pts == &ts) { // recalculate the timeout qint64 xtimeout = qint64(timeout) * 1000 * 1000; xtimeout -= elapsedTimer.nsecsElapsed(); @@ -202,8 +205,9 @@ bool lockInternal_helper(QBasicAtomicPointer<QMutexData> &d_ptr, int timeout = - } ts.tv_sec = xtimeout / Q_INT64_C(1000) / 1000 / 1000; ts.tv_nsec = xtimeout % (Q_INT64_C(1000) * 1000 * 1000); - pts = &ts; } + if (IsTimed) + pts = &ts; // successfully set the waiting bit, now sleep int r = _q_futex(&d_ptr, FUTEX_WAIT, quintptr(dummyFutexValue()), pts); |