Re: [GIT PULL] nohz: Fix double clock write on idle ticks
From: Ingo Molnar
Date: Sun Aug 24 2014 - 06:07:43 EST
* Frederic Weisbecker <fweisbec@xxxxxxxxx> wrote:
> From: Frederic Weisbecker <fweisbec@xxxxxxxxx>
> Please pull the nohz/drop-double-write-v3 branch that can be found at:
> Although the 1st patch fixes a bug, it was a longstanding issue so
> that branch doesn't need to be applied in 3.17. The next merge window
> looks better.
> The tick reschedules itself unconditionally. It's relevant in periodic
> mode but not in dynticks mode where it results in spurious double clock
> writes and even spurious periodic behaviour for low-res case.
> This set fixes that:
> * 1st patch removes low-res periodic tick rescheduling in nohz mode.
> This fixes spurious periodic behaviour.
> * 2nd patch does the same for high-res mode. Here there is no such
> spurious periodic behaviour but it still spares a double clock write
> in some cases.
> Viresh Kumar (2):
> nohz: Fix spurious periodic tick behaviour in low-res dynticks mode
> nohz: Avoid tick's double reprogramming in highres mode
> kernel/time/tick-sched.c | 8 ++++++++
> 1 file changed, 8 insertions(+)
These fixes are pretty small - any objections against putting it into
timers/urgent and including it in v3.17?
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/