From a94c960b75453ef2eb9dca0be1db426de7a1091d Mon Sep 17 00:00:00 2001 From: Thiago Macieira Date: Wed, 30 Jun 2010 15:18:24 +0200 Subject: [PATCH] Unix (non-Glib) event dispatcher: round sleep to millisecond boundary. If we have two timers running in an application with the same timeout and started almost at the same time by the code, they would trigger two sleeps, the second of which very short (under a millisecond). This causes us to match the Glib and Windows event loops, which round all timers to millisecond anyway. Change-Id: I7eb531e02dadf75925c01192b0f33ef3641ae1ea Reviewed-by: Olivier Goffart --- src/corelib/kernel/qeventdispatcher_unix.cpp | 16 +++++++++++++++- 1 file changed, 15 insertions(+), 1 deletion(-) diff --git a/src/corelib/kernel/qeventdispatcher_unix.cpp b/src/corelib/kernel/qeventdispatcher_unix.cpp index f2f9dd6..3c7a48a 100644 --- a/src/corelib/kernel/qeventdispatcher_unix.cpp +++ b/src/corelib/kernel/qeventdispatcher_unix.cpp @@ -441,6 +441,20 @@ void QTimerInfoList::timerRepair(const timeval &diff) } } +static timeval roundToMillisecond(timeval val) +{ + // always round up + // worst case scenario is that the first trigger of a 1-ms timer is 0.999 ms late + + int us = val.tv_usec % 1000; + val.tv_usec += 1000 - us; + if (val.tv_usec > 1000000) { + val.tv_usec -= 1000000; + ++val.tv_sec; + } + return val; +} + /* Returns the time to wait for the next timer, or null if no timers are waiting. @@ -464,7 +478,7 @@ bool QTimerInfoList::timerWait(timeval &tm) if (currentTime < t->timeout) { // time to wait - tm = t->timeout - currentTime; + tm = roundToMillisecond(t->timeout - currentTime); } else { // no time to wait tm.tv_sec = 0; -- 2.7.4