Re: [tip:timers/core] timerfd: Allow timers to be cancelled whenclock was set

From: Kay Sievers
Date: Wed May 11 2011 - 11:50:30 EST


On Wed, May 11, 2011 at 16:48, Peter Zijlstra <peterz@xxxxxxxxxxxxx> wrote:
> On Wed, 2011-05-11 at 16:32 +0200, Kay Sievers wrote:
>> On Wed, May 11, 2011 at 16:30, Peter Zijlstra <peterz@xxxxxxxxxxxxx> wrote:
>> > On Wed, 2011-05-11 at 16:22 +0200, Kay Sievers wrote:
>> >> On Wed, May 11, 2011 at 16:01, Peter Zijlstra <peterz@xxxxxxxxxxxxx> wrote:
>> >> > On Wed, 2011-05-11 at 15:52 +0200, Kay Sievers wrote:
>> >> >>
>> >> >> No, fixed time spans have never been a problem, and are not the
>> >> >> example here. It's about the normal wall clock, that wakes up every
>> >> >> minute and updates the numbers on the screen.
>> >> >
>> >> > 'wakes up every minute' sounds like a fixed time interval to me.
>> >>
>> >> Right, but if the wall clock changes, it must not wait for the full
>> >> minute to update the numbers, they need to update immediately with the
>> >> new wall clock time. Stuff woke up every second in the past to do
>> >> that, but that's not what we want today.
>> >
>> > Again, nothing that couldn't be solved with a notifier of sorts.
>>
>> Right. What we have with that patch, and what's visible to the
>> outside, is nothing but such a notifier. What kind of interface you
>> have in mind instead?
>
> Dunno, an eventfd that triggers every time someone calls adjtime() and
> related?

I think, we are exactly not interested in adjtime() calls, but only in
jumps in wall clock time.

Kay
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