[ntp:questions] Re: announce: PPSkit-2.1.2 for Linux 2.4.21

David L. Mills mills at udel.edu
Fri Sep 5 14:58:40 UTC 2003


Terje,

The nanokernel and simulator work extremely well even if the various
CPUs salute different clock rates. I've never seen a case where this is
an issue. I do realize this technology is several years old as in the
Tru64 kernel and may need to be rediscovered on a regular basis.

Dave

Terje Mathisen wrote:
> 
> David Schwartz wrote:
> > "Terje Mathisen" <terje.mathisen at hda.hydro.com> wrote in message
> > news:bj5hpv$m0a$2 at osl016lin.hda.hydro.com...
> >
> >
> >>TSC is mostly useless on SMP machines unfortunatly, unless you can pin
> >>your process, including all PPS interrupt handlers, to a single CPU.
> >
> >
> >     Or if you can sync the TSCs, like Linux does.
> 
> Only possible on machines where all cpus are the same speed, i.e. same
> multiplier (but that's not much of a problem, right?). However, I've
> been told (but without any satisfactory explanation) in comp.arch that
> it's effectively impossible to keep them really synchronized.
> 
> I guess I'll have to do some /usr/src spelunking!
> ...
> 
> Terje
> 
> --
> - <Terje.Mathisen at hda.hydro.com>
> "almost all programming can be viewed as an exercise in caching"



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