Re: [PATCH 0/3] Add walltime support for ring-buffer

KOSAKI Motohiro
2009-08-03T09:32:15Z

>
> * KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com> wrote:
>
> > It can. but I don't think it is sufficient. On flight recorder
> > use-case, The tracing run more than one year. And, Administrator
> > only see last N sec log. (previous logs were overwritten by
> > ring-buffer go-around)
>
> That's definitely something we want to enable ASAP.
>
> I'm wondering why a single u64 timestamp is not enough to express
> the full, absolute range of time elapsed since bootup, in
> nanoseconds.
>
> That would make walltime a matter of pretty-printing only - we'd
> have to convert the u64 nsec timestamp into a walltime format,
> right?
>
> In fact we could change all the timestamps to be standardized along
> 'nanoseconds elapsed since 1970' or so - not nanoseconds since the
> last bootup. That still fits just fine within 64 bits - u64
> nanoseconds has a scope of 500+ years.

Ah, you are right. thanks correct me.
but I think ntp updating time storing is necessary too.