Timekeeping [Was: Re: cvs commit: src/usr.bin/vmstat vmstat.c src/usr.bin/w w.c]

Andre Oppermann oppermann at networx.ch
Fri Oct 21 10:14:09 PDT 2005


Poul-Henning Kamp wrote:
> 
> In message <435913FE.774C683D at freebsd.org>, Andre Oppermann writes:
> 
> >> Again, if you have been sitting in DDB, what exactly is the definition
> >> of "uptime" ?
> >
> >IMO it's this:
> >
> > Uptime is the time the operating was available to present it's common
> > services to userland.  That excludes any suspend and ddb times.  Single
> > user mode however counts because the OS was servicing userland even if
> > there was only one user.  Uptime is represented in SI seconds.
> 
> I can live with this definition.
> 
> So now we just need to be able to reliably measure the "not-uptime".

Umm...  Whenever the onesec tick is not incrementing the uptime (and
monotonic) counter.  Which conviniently already is the case when OS is
suspended or in DDB.

-- 
Andre


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