RE: Problems with fast timeouts

["Torti, Richard A" <richard a torti boeing com>]

You will not be able to guarantee 5ms intervals without patching the kernel
in some manner.  The exception, I believe, is Red Hat 8.0, which runs the
kernel at 512 Hz (??? I think this is true, someone correct me if I'm
wrong.).  I think future versions of the kernel are supposed to run at 1kHz,
meaning within another year, this won't be an issue.

Rich
> -----Original Message-----
> From: Krzysztof Dubowik [mailto:kite interia pl]
> Sent: Monday, January 06, 2003 3:03 AM
> To: gtk-list gnome org
> Subject: Re: Problems with fast timeouts
> 
> 
> > > [ i am assuming that you are working on linux, which 
> might be a big
> > >   assumption. if not, then ignore all that i write here. ]
> > >
> > > you're using a multitasking, multiuser operating system with a
> > > scheduling granularity of 10ms. the kernel will to honor the 5ms
> > > request but will fail to provide it because it only 
> inspects the timer
> > > queues 100 times a second. unless you build/use a kernel 
> with HZ=1000,
> > > and/or use real-time scheduling, nothing can get you 
> timing intervals
> > > of less than 10ms under linux. your 20ms timing interval 
> is probably a
> > > reflection of average times.
> > >
> > > --p
> > 
> > Even if you are using windows, you have a multitasking 
> operating system
> > with a 
> > special interrupt every 10ms that selects the next thread.
> > 
> > Karsten
> 
> I am poting my application from Windows MFC (where is does 
> happily 5ms timeouts) to Linux. I would rather have my 
> application to run on a standard kernel, so what's the 
> solution? Where do I learn about realtime scheduling?
> 
> Regards,
> -- 
> Krzysztof
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