linux-kernel - Re: [PATCH] rtc: adapt allowed RTC update error

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Date:   Wed, 2 Dec 2020 16:07:25 +0100
From:   Miroslav Lichvar <mlichvar@...hat.com>
To:     Thomas Gleixner <tglx@...utronix.de>
Cc:     Jason Gunthorpe <jgg@...pe.ca>, linux-kernel@...r.kernel.org,
        John Stultz <john.stultz@...aro.org>,
        Prarit Bhargava <prarit@...hat.com>
Subject: Re: [PATCH] rtc: adapt allowed RTC update error

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.

Thanks,

-- 
Miroslav Lichvar