Re: [PATCHv2] timekeeping: Update multiplier when NTP frequency is set directly

From: Thomas Gleixner
Date: Fri Jun 22 2018 - 17:28:17 EST


On Fri, 22 Jun 2018, John Stultz wrote:
> On Fri, Jun 22, 2018 at 2:09 PM, Thomas Gleixner <tglx@xxxxxxxxxxxxx> wrote:
> > On Mon, 4 Jun 2018, Miroslav Lichvar wrote:
> >
> >> When the NTP frequency is set directly from userspace using the
> >> ADJ_FREQUENCY or ADJ_TICK timex mode, immediately update the
> >> timekeeper's multiplier instead of waiting for the next tick.
> >>
> >> This removes a hidden non-deterministic delay in setting of the
> >> frequency and allows an extremely tight control of the system clock
> >> with update rates close to or even exceeding the kernel HZ.
> >>
> >> The update is limited to archs using modern timekeeping
> >> (!ARCH_USES_GETTIMEOFFSET).
> >
> > John ?????
>
> Yea. I've got this in my toqueue list. I'm going to take another pass
> at testing and hopefully send it your way.

No hurry. I just wanted to make sure that it didn't fall through the
cracks.

Thanks,

tglx