[LAU] Realtime Kernel

Mark Knecht markknecht at gmail.com
Tue Mar 18 15:36:34 EDT 2008


That kernel is getting pretty old. I'm running 2.6.24-rt1 here. you
might want to check out the RT-Wiki or some of the sites for using RT
kernels with audio apps.

http://rt.wiki.kernel.org/index.php/Main_Page

The above link gives instructions for patching a kernel to get to an RT kernel.

Hope this helps,
Mark

On Tue, Mar 18, 2008 at 12:02 PM, Arda Eden <ardaeden at gmail.com> wrote:
> Hmm,
> So this is all about my kernel:
> Linux melinda 2.6.18.8-86 #2 SMP Mon Feb 11 00:50:59 EET 2008 i686 mobile
> AMD Athlon(tm) XP-M 2200+ GNU/Linux
>
> Is it possible to patch it in order to make it a RT kernel ?
>
>
> On Tue, Mar 18, 2008 at 8:59 PM, Mark Knecht <markknecht at gmail.com> wrote:
> >
> > On Tue, Mar 18, 2008 at 11:41 AM, Arda Eden <ardaeden at gmail.com> wrote:
> > > So what does a realtime kernel change ? Makes my latency 1 ms ?
> > >
> > >
> > >
> > >
> > > On Tue, Mar 18, 2008 at 8:38 PM, Arnold Krille <arnold at arnoldarts.de>
> wrote:
> > >
> > > >
> > > >
> > > >
> > > > Am Dienstag, 18. März 2008 schrieb Mark Knecht:
> > > >
> > > > > On Tue, Mar 18, 2008 at 11:25 AM, Arda Eden <ardaeden at gmail.com>
> wrote:
> > > > > > So is it really necessary to have a realtime kernel in order to
> use
> > > linux
> > > > > > audio applications without any latencies or xruns ?
> > > > > It is not possible to use ANY kernel with NO latencies. EVERY kernel
> > > > > has latencies. The question is how low do you want the latencies to
> > > > > be? If you can exist with 50mS or higher you might get away with a
> > > > > standard kernel. If you want to run with 1.2mS latency then you will
> > > > > absolutely have to have a real-time enabled kernel.
> > > >
> > > > Still it has to be noted that you can achieve 5ms latency without a
> > > > RT-kernel... Even with an el-cheapo builtin soundcard...
> > > >
> > > > Arnold
> >
> > Absolutely. The most recent kernels are often quite good. However I
> > would say that the difference between a standard kernel running 5mS
> > and a RT kernel running 5mS is that the RT kernel is far more likely
> > to meet the 5mS requirement under heavy system loads while the
> > standard kernel may, at times, give a bit too much time to non-rt
> > threads and not get back to your audio thread as fast as someone might
> > want.
> >
> > If you want the highest reliability means of meeting your RT
> > requirements all the time then use the RT kernel. If you are just
> > doing home recording and can accept an occasional xrun (i.e. - a
> > glitch in the recorded data) then stick with the standard kernel for
> > as long as it works for you.
> >
> > Just my view,
> > Mark
> >
>
>
>
> --
> Arda EDEN
> Cumhuriyet University
> Faculty of Fine Arts
> Department of Music Technology
> Sivas/TURKEY



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