Hello!
The following three patches provide some crude timer-wheel latency
patches. I understand that a more comprehensive solution is in progress,
but in the meantime, these patches work well in cases where a given
CPU has either zero or one timers pending, which is a common case for
NO_HZ_FULL kernels. So, on the off-chance that this is helpful to
someone, the individual patches are as follows:
1. Add ->all_timers field to tbase_vec to count all timers, not
just the non-deferrable ones.
2. Avoid jiffy-at-a-time stepping when the timer wheel is empty.
3. Avoid jiffy-at-a-time stepping when the timer wheel transitions
to empty.
4. Avoid jiffy-at-a-time stepping after a timer is added to an
initially empty timer wheel.
Differences from v1:
o Fix an embarrassing bug located by Oleg Nesterov where the
timer wheel could be judged to be empty even if it contained
deferrable timers.
Thanx, Paul
------------------------------------------------------------------------
b/kernel/timer.c | 22 ++++++++++++++++++++++
1 file changed, 22 insertions(+)
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majord...@vger.kernel.org
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/
