https://sourceware.org/git/gitweb.cgi?p=newlib-cygwin.git;h=ea99e9fdda42141ef1c2273943a33d3191d72844
commit ea99e9fdda42141ef1c2273943a33d3191d72844 Author: Corinna Vinschen <[email protected]> Date: Mon Jan 21 11:14:16 2019 +0100 Cygwin: timerfd: fix overrun computation - Drop erroneous initial computation of overrun count in settime for absolute non-realtime clocks. It's repeated in thread_func and thus counted twice. - Fix overrun computation for timestamp offsets being a multiple of the timer interval. The timestamp has to be corrected after the first offset, otherwise the correction loop counts the intervals again. Signed-off-by: Corinna Vinschen <[email protected]> Diff: --- winsup/cygwin/timerfd.cc | 21 +++++++++++---------- 1 file changed, 11 insertions(+), 10 deletions(-) diff --git a/winsup/cygwin/timerfd.cc b/winsup/cygwin/timerfd.cc index 64836b0..0a04241 100644 --- a/winsup/cygwin/timerfd.cc +++ b/winsup/cygwin/timerfd.cc @@ -155,13 +155,18 @@ timerfd_tracker::thread_func () /* Make concessions for unexact realtime clock */ if (ts > now) ts = now - 1; - increment_overrun_count ((now - ts + get_interval () - 1) - / get_interval ()); + LONG64 ov_cnt = (now - ts + get_interval () - 1) + / get_interval (); + increment_overrun_count (ov_cnt); + ts += get_interval () * ov_cnt; /* Set exp_ts to current timestamp. Make sure exp_ts ends up bigger than "now" and fix overrun count as required */ - while ((ts += get_interval ()) <= (now = get_clock_now ())) - increment_overrun_count ((now - ts + get_interval () - 1) - / get_interval ()); + while (ts <= (now = get_clock_now ())) + { + increment_overrun_count ((now - ts + get_interval () - 1) + / get_interval ()); + ts += get_interval (); + } set_exp_ts (ts); /* NtSetTimer allows periods of up to 24 days only. If the time is longer, we set the timer up as one-shot timer for each @@ -536,11 +541,7 @@ timerfd_shared::arm_timer (int flags, const struct itimerspec *new_value) /* If the timestamp was earlier than now, compute number of overruns and offset DueTime to expire immediately. */ if (DueTime.QuadPart >= 0) - { - LONG64 num_intervals = DueTime.QuadPart / _interval; - increment_overrun_count (num_intervals); - DueTime.QuadPart = -1LL; - } + DueTime.QuadPart = -1LL; } } else
