Re: TSC to Mono-raw Drift
From: Thomas Gleixner
Date: Thu Nov 01 2018 - 13:45:16 EST
On Tue, 23 Oct 2018, John Stultz wrote:
> On Fri, Oct 19, 2018 at 3:36 PM, John Stultz <john.stultz@xxxxxxxxxx> wrote:
> I spent a little bit of time thinking this out. Unfortunately I don't
> think its a simple matter of calculating the granularity error on the
> raw clock and adding it in each interval. The other trouble spot is
> that the adjusted clocks (monotonic/realtime) are adjusted off of that
> raw clock. So they would need to have that error added as well,
> otherwise the raw and a otherwise non-adjusted monotonic clock would
> drift.
>
> However, to be correct, the ntp adjustments made would have to be made
> to both the base interval + error, which mucks the math up a fair bit.
Hmm, confused as usual. Why would you need to do anything like that?
Thanks,
tglx