[gentoo-amd64] AMD64 - 2.6.14-rc2-rt7 - great for real time audio

[gentoo-amd64] AMD64 - 2.6.14-rc2-rt7 - great for real time audio

[Mark Knecht]

Hi,
   For folks that are interested in this sort of stuff yesterday I
built linux-2.6.14-rc2-rt7 on my NForce4/Gentoo AMD64 system. I've
been running Jack and streaming audio for hours now at 128/2 with no
xruns, all while browsing the web and doing emerges. So far the
results are very promising. SATA drive usage had been creating xrun
problems, but that's not there in this kernel, at least at 128/2. I'm
using both SATA and 1394 drives for the audio. For kicks at the same
time I'm playing a movie using xine with my EIDE DVD drive and the
on-board NVidia sound chip. No xruns at all even though I'm using
SATA, 1394 and EIDE all at the same time.

   Check it out if your interested. I used 2.6.13, patched with
patch-2.6.14-rc2 and then patched that with patch 2.6.14.-rc2-rt7.
Configuring the kernel was NOT easy in my case, but I eventually got
it going and I'm happy I did.

   I tried ck-sources but didn't have any luck. Too bad as I like the
email list. Very helpful folks.

   Too bad we don't have an official or even semi-official
gentoo-rt-audio-sources project for kernels like this/

Cheers,
Mark

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Re: [gentoo-amd64] AMD64 - 2.6.14-rc2-rt7 - great for real time audio

[Tres Melton]

Mark,

	You have had so many problems with the other kernels doing this stuff
and now that you have found a good one I really think that you should
compose a message entitled "Latencies in the kernel" and post a summary
of your experiences with the various kernels to the LKML.  I think that
it would benefit the developers (and all of us) to know that the kernel
seems to be tuned rather nicely now to tasking these things.  Anyway,
I'm glad that it is working for you.

Regards,
Tres


On Fri, 2005-09-30 at 10:47 -0700, Mark Knecht wrote:
> Hi,
>    For folks that are interested in this sort of stuff yesterday I
> built linux-2.6.14-rc2-rt7 on my NForce4/Gentoo AMD64 system. I've
> been running Jack and streaming audio for hours now at 128/2 with no
> xruns, all while browsing the web and doing emerges. So far the
> results are very promising. SATA drive usage had been creating xrun
> problems, but that's not there in this kernel, at least at 128/2. I'm
> using both SATA and 1394 drives for the audio. For kicks at the same
> time I'm playing a movie using xine with my EIDE DVD drive and the
> on-board NVidia sound chip. No xruns at all even though I'm using
> SATA, 1394 and EIDE all at the same time.
> 
>    Check it out if your interested. I used 2.6.13, patched with
> patch-2.6.14-rc2 and then patched that with patch 2.6.14.-rc2-rt7.
> Configuring the kernel was NOT easy in my case, but I eventually got
> it going and I'm happy I did.
> 
>    I tried ck-sources but didn't have any luck. Too bad as I like the
> email list. Very helpful folks.
> 
>    Too bad we don't have an official or even semi-official
> gentoo-rt-audio-sources project for kernels like this/
> 
> Cheers,
> Mark
> 
-- 
Tres Melton
IRC & Gentoo: RiverRat

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[gentoo-amd64] Re: AMD64 - 2.6.14-rc2-rt7 - great for real time audio

[Duncan]

Tres Melton posted <1128118297.6208.265.camel@thor.tres.org>, excerpted
below,  on Fri, 30 Sep 2005 16:11:37 -0600:

> 	You have had so many problems with the other kernels doing this stuff
> and now that you have found a good one I really think that you should
> compose a message entitled "Latencies in the kernel" and post a summary
> of your experiences with the various kernels to the LKML.  I think that
> it would benefit the developers (and all of us) to know that the kernel
> seems to be tuned rather nicely now to tasking these things.  Anyway,
> I'm glad that it is working for you.

Note that it's not the vanilla kernel, but the vanilla kernel with the
real-time patches.  

Still, yes, posting something to LKML is a good idea, as one of the
ongoing debates has to do with the merits of the various real-time patches
as opposed to other factors, and this sort of direct user testimony could
be influential.  Of course, don't be surprised if you immediately get
asked to do testing on RT related stuff!

(Noting that I dont' follow LKML directly, but do follow happenings in
general thru LWN's weekly coverage and occasionally find myself browsing
various LKML threads as well.)

-- 
Duncan - List replies preferred.   No HTML msgs.
"Every nonfree program has a lord, a master --
and if you use the program, he is your master."  Richard Stallman in
http://www.linuxdevcenter.com/pub/a/linux/2004/12/22/rms_interview.html


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Re: [gentoo-amd64] Re: AMD64 - 2.6.14-rc2-rt7 - great for real time audio

[Mark Knecht]

On 9/30/05, Duncan <1i5t5.duncan@cox.net> wrote:
> Tres Melton posted <1128118297.6208.265.camel@thor.tres.org>, excerpted
> below,  on Fri, 30 Sep 2005 16:11:37 -0600:
>
> >       You have had so many problems with the other kernels doing this stuff
> > and now that you have found a good one I really think that you should
> > compose a message entitled "Latencies in the kernel" and post a summary
> > of your experiences with the various kernels to the LKML.  I think that
> > it would benefit the developers (and all of us) to know that the kernel
> > seems to be tuned rather nicely now to tasking these things.  Anyway,
> > I'm glad that it is working for you.

Yes, I've now moved a bit forward to 2.6.14-rc3-rt1. It seems to be
working slightly better. On the previous 2.6.14-rc2-rt7 I had a few
times where I got a short burst of xruns. This happened at sort of odd
times, but it happened. While I've only run the new one since
yesterday I've seen this happen fewer times, and with fewer xruns. Not
sure I trust data like that, but it's what I've seen.

As for writing the LKML, I could do that. I have reported that these
kernels are working pretty well. I think I'd like to build Con
Kolivas's kernel from source, just to ensure that any patches put
there by gentoo are not the cause of the problems I'm seeing. Jack is
possibly being given real time priorities than these other kernels
I've just built, or so I think. Not at all sure. Don't want to say
much more about that until I know more. These email threads have a way
of lasting for years and becoming urban legends. So many people seem
happy with ck-sources so I think if it doesn't work for me it must be
me.

>
> Note that it's not the vanilla kernel, but the vanilla kernel with the
> real-time patches.
>
> Still, yes, posting something to LKML is a good idea, as one of the
> ongoing debates has to do with the merits of the various real-time patches
> as opposed to other factors, and this sort of direct user testimony could
> be influential.  Of course, don't be surprised if you immediately get
> asked to do testing on RT related stuff!

Yes, I have to watch out for this. I recently signed up to look after
some audio apps under Wine. I think that will keep me quite busy.

>
> (Noting that I dont' follow LKML directly, but do follow happenings in
> general thru LWN's weekly coverage and occasionally find myself browsing
> various LKML threads as well.)

Thanks for writing.

Cheers,
Mark

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Re: [gentoo-amd64] Re: AMD64 - 2.6.14-rc2-rt7 - great for real time audio

[Billy Holmes]

Mark Knecht wrote:
> of lasting for years and becoming urban legends. So many people seem
> happy with ck-sources so I think if it doesn't work for me it must be
> me.

the ck kernel has specific uses. It's main purpose is to be a good 
desktop kernel with a concentration on interactivity. This goal does 
parallel with the goal of audio users, however, I believe there are 
differences in latency tolerances between those two camps (the desktop 
user and the audio user).

I personally use it on a production terminal server running gentoo with 
about 15 users. The ck kernel performs flawlessly. I'm about to upgrade 
to the newer one, as Con has just stabilized the swap-prefetching 
feature that I would love to offer to my users.
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