--- In "JD" <> wrote:
>
> Looks interesting, and looking at the kernel syms, it is already
> compiled in and I can see two timers in /proc/timer_list
>
> How do you set it to sub HZ timing tho?
>
> --- In "charliem_1216" <charliem_1216@> wrote:
> >
> >
> > Hi --
> >
> > --- In "JD" <john.donoghue@> wrote:
> > >
> > > Well, scheduling using kernel timers is only going to give me a
> > > frequency of at most 'HZ'
> > >
> > > Which brings us back incrementing HZ, or using some other method.
> > >
> >
> > You are using 7800, which means a 2.6 kernel, right? Have you looked
> > at enabling high resolution timers (HRT) when building your kernel?
> > They work quite well on my TS-7250, but I have no TS-7800 to try.
> > Check out Documentation/hrtimers in your linux kernel directory. If
> > built with HRT, the kernel will use hr timers for nanosleep(),
> > itimers, and posix-timers.
> >
> > BTW, there was a post here with a link to the marvel chip docs, even
> > if they have not been officially released.
> >
> > Regards, ....... Charlie
> >
>
If you see ".resolution: 1 nsecs" and "event_handler:
hrtimer_interrupt" when you "cat /proc/timer_list", then you are in
good shape and there is nothing else to set AFAIK. Just use normal
nanosleep and posix-timer calls.
You can find some basic info at:
http://elinux.org/High_Resolution_Timers
and more detailed info at:
http://www.kernel.org/pub/linux/kernel/people/tglx/hrtimers/ols2006-hrtimers.pdf
An easy way to test your system wrt hrt is:
http://rt.wiki.kernel.org/index.php/Cyclictest
Regards, ............ Charlie
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