[ardour-users] OT - 2.6.11 kernels for audio

[Fernando Lopez-Lezcano]

On Mon, 2005-04-11 at 13:21, Mark Knecht wrote:
> Thanks Fernando. I found that a few minutes ago. Good to know at least
> I'm Googling out the right stuff.
> 
> Can you tell me what set of patches you deem necessary to make a good
> audio kernel these days? Last October there were 4 patches that I
> applied. I've forgotten what they all do:
> 
> 1) I started with 2.6.8 from kernel.org I believe
> 2) Added 2.6.9_rc2 which I think got 2.6.8 up to 2.6.9_rc2.
> 3) I added 2.6.9-rc2-mm4 - I don't know what that is.
> 4) I then added VP-2.6.9-rc2-mm4-S7. I think that was Ingo's patch
> 5) Lastly I added the LSM patch - realtime-lsm-2.6.8.1 which I guess
> gives me access to all of this as a user, correct?
> 
> What part of those is still required? All? Has anythign made it into
> the kernel proper these days?

A lot has made it into the plain kernel, so you have two choices:
a) use plain 2.6.x where x >= 2.6.10
   more stable, decent latency
b) use plain 2.6.x + Ingo's patches
   current latest would be:
     2.6.11 (plain) +
     patch-2.6.12-rc2.bz2 + 
     realtime-preempt-2.6.12-rc2-RT-V0.7.45-01
   better latency, perhaps not so stable (have not tried this particular
   combination yet - still compiling :-)

You also need realtime-lsm on top of either to run stuff as non-root
-- Fernando

> On 11 Apr 2005 13:14:23 -0700, Fernando Lopez-Lezcano
> <nando at ccrma.stanford.edu> wrote:
> > On Mon, 2005-04-11 at 13:03, Mark Knecht wrote:
> > > On Apr 11, 2005 12:56 PM, Rob Fell <robin.fell at ntlworld.com> wrote:
> > > > Mark Knecht wrote:
> > > > >    Anyone doing 2.6.11 yet? What's your experience? How did you patch
> > > > > to make Ardour work well.
> > > >
> > > > I'm currently running 2.6.11-rc4-RT-V0.7.39-02.  Stock sources plus
> > > > Ingos RT patches.
> > >
> > > That sounds about like what I'm looking for. My current kerenl before
> > > trying to jump up to 2.6.11 is 2.6.9-rc2-mm4-VP-S7 and then
> > > variations. (-lsm, noACPI, etc.)  I did all of this last October and
> > > then promptly forgot what's what. Every time this is a learning
> > > experience.
> > >
> > > Can you point me toward Ingo's stuff. I'm trying to Google for it but
> > > I seem to be buried in nothing but lkml emails...
> > 
> >   http://people.redhat.com/~mingo/realtime-preempt/
> > needs 2.6.12-rc2
> > (currently building it :-)
> > -- Fernando
> > 
> > > > Since I'm using the ZLM on my delta-1010 I don't run particularly low
> > > > latencies - I have been able to get reliable 5ms(ish) on my now ageing
> > > > 1.3GHz Duron.  Apparently there is an issue with my kernel between ext3
> > > > and low-lat performance - which explains why I'm not able to go below
> > > > 5ms(ish) reliably.
> > > >
> > > > If I were doing it again I'd either (a) check-out the Gentoo kernels, or
> > > > (b) pick a kernel to match Ingos latest RT patchset.
> > >
> > > Yeah, I should probably pay more attention to possibly the ck kernel?
> > > Any comments from your perspective on which kernel might be the best
> > > for running low latency audio as a normal user?
> > >
> > > Thanks much,
> > > Mark
> > 
> >