Re: [PATCH] rtc: adapt allowed RTC update error

From: Thomas Gleixner
Date: Wed Dec 02 2020 - 13:37:32 EST


On Wed, Dec 02 2020 at 16:36, Miroslav Lichvar wrote:
> On Wed, Dec 02, 2020 at 04:07:28PM +0100, Miroslav Lichvar wrote:
>> On Wed, Dec 02, 2020 at 02:44:53PM +0100, Thomas Gleixner wrote:
>> > Something like the completely untested below should make this reliable
>> > and only needs to retry when the work is running late (busy machine),
>> > but the wakeup will be on time or at max 1 jiffie off when high
>> > resolution timers are not available or disabled.
>>
>> It seems to work nicely. In my test most of the updates succeeded on
>> the first attempt hitting the right tick, the rest succeeding on the
>> second attempt. Only when the clock was set to run 10% faster, it
>> needed few more attempts to converge to the target time.
>
> I noticed an observable change wrt adjtimex() calls though. It seems
> it now reschedules the RTC update, i.e. there can be more than one
> update per 11 minutes. Was this intended?

No. Let me fix that.

Thanks,

tglx