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[ts-7000] Re: Changing HZ on 7800

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Subject: [ts-7000] Re: Changing HZ on 7800
From: "JD" <>
Date: Tue, 08 Jan 2008 19:22:41 -0000
Looking at time_list, it lists the resolution as 10000000 ns so I
guess it isnt fully implemented in the kernel?

Or i need do something else?

--- In  "charliem_1216" <> wrote:
>
> --- In  "JD" <john.donoghue@> 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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