Re: [RFC][PATCH 4/4] time: Do leapsecond adjustment in gettime fastpaths

[John Stultz]

On Tue, Jun 2, 2015 at 2:21 AM, Peter Zijlstra <peterz@xxxxxxxxxxxxx> wrote:
> On Tue, Jun 02, 2015 at 11:01:54AM +0200, Ingo Molnar wrote:
>> > Currently, leapsecond adjustments are done at tick time.
>> >
>> > As a result, the leapsecond was applied at the first timer
>> > tick *after* the leapsecond (~1-10ms late depending on HZ),
>> > rather then exactly on the second edge.
>
> So why not program a hrtimer to expire at the exact right time? Then
> even the VDSO gets its time 'right' and you avoid touching all the
> fast paths.

Well, the hrtimer won't always expire at the exact right time (due to
irq latency, possible clockevent drift/error, etc) , so that would
close the window a bit, but wouldn't eliminate the issue.

thanks
-john
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