16 Jan
2004
16 Jan
'04
3:13 p.m.
I've been using a 2.4.2 kernel with Andrew Morton's patches and I got
jack to work very well. However, seeing 2.6 is the latest and greatest
I'd like to switch but am having no luck thus far.
Q. If anyone has got jack to work great with a 2.6(.1) kernel could you
share with me what version of the 2.6 kernel you used and what patches
(if any)
At the moment I'm trying a 2.6.1 with an mm4 patch but I'm getting no
sound with my soundblaster live.
I've done:
<*> Sound card support
and, under Advanced Linux Sound Architecture --->
<*> Advanced Linux Sound Architecture
<*> Sequencer support
<*> OSS API emulation
<*> OSS Mixer API
<*> OSS PCM (digital audio) API
<*> OSS Sequencer API
rebooted and install alsa-lib-1.0.1 and alsa-utils-1.0.1 as well but I
get these errors
root@upstairs glenn # aplay /usr/kde/3.2/share/sounds/pop.wav
ALSA lib pcm_hw.c:1055:(snd_pcm_hw_open) open /dev/snd/pcmC0D0p failed:
No such file or directory
aplay: main:502: audio open error: No such file or directory
and
glenn@upstairs glenn $ alsamixer
No mixer elems found
I'm at a loss but am interested at what type of kernel others are using.
I think my next best bet is to remove alsa from the kernel and install
it seperately.
Thanks
16 Jan
16 Jan
5:37 p.m.
rebooted and install alsa-lib-1.0.1 and
alsa-utils-1.0.1 as well but I
get these errors
root@upstairs glenn # aplay /usr/kde/3.2/share/sounds/pop.wav
ALSA lib pcm_hw.c:1055:(snd_pcm_hw_open) open /dev/snd/pcmC0D0p failed:
No such file or directory
aplay: main:502: audio open error: No such file or directory
I'm not totally sure, but if devfs is not in the kernel, you should also
run snddevices script from alsa-driver.
It will create the /dev entries needed for alsa.
Tommi Uimonen
17 Jan
17 Jan
4:06 a.m.
Tommi Sakari Uimonen wrote:
Also, did you set the modules to load in modprobe.conf, used by 2.6.x
(instead of modules.conf which is used by 2.4.x) to load modules
(copy-paste the settings). Definitly it is also advisable to run
snddevices (if this is your first time using ALSA).
rebooted and
install alsa-lib-1.0.1 and alsa-utils-1.0.1 as well but I
get these errors
root@upstairs glenn # aplay /usr/kde/3.2/share/sounds/pop.wav
ALSA lib pcm_hw.c:1055:(snd_pcm_hw_open) open /dev/snd/pcmC0D0p failed:
No such file or directory
aplay: main:502: audio open error: No such file or directory
I'm not totally sure, but if devfs is not in the kernel, you should also
run snddevices script from alsa-driver.
It will create the /dev entries needed for alsa.
Tommi Uimonen
6:25 a.m.
modprobe.conf and modules.conf have the same sound related entries.
Where is snddevices found? I can't install alsa-driver when alsa is
built in and even if I exclude alsa from the kernel I still can't
install it. I'm just going to try a straight 2.6.1 kernel (no patches).
I got sound with the 2.6 by doing this but had dreadful jack
performance. Here goes...
/dev/snd/pcmC0D0p failed:
This file exists and I gave it full permissions. But no luck for me.
Gian Paolo Mureddu wrote:
Tommi Sakari Uimonen wrote:
Also, did you set the modules to load in modprobe.conf, used by 2.6.x
(instead of modules.conf which is used by 2.4.x) to load modules
(copy-paste the settings). Definitly it is also advisable to run
snddevices (if this is your first time using ALSA).
rebooted
and install alsa-lib-1.0.1 and alsa-utils-1.0.1 as well but I
get these errors
root@upstairs glenn # aplay /usr/kde/3.2/share/sounds/pop.wav
ALSA lib pcm_hw.c:1055:(snd_pcm_hw_open) open /dev/snd/pcmC0D0p failed:
No such file or directory
aplay: main:502: audio open error: No such file or directory
I'm not totally sure, but if devfs is not in the kernel, you should also
run snddevices script from alsa-driver.
It will create the /dev entries needed for alsa.
Tommi Uimonen
15 Feb
15 Feb
4:39 p.m.
Has there been any more said about bringing the low-latency of the 2.6
kernel up to the qualtiy of the 2.4? I see Andrew Morton's mm sources
have now reached 2.6.3-rc2-mm1 but there doesn't seem to be any mention
about improved latency.
7:16 p.m.
I think much (most? all?) of the lowlatency patch set was merged into
the 2.6.1 release. I'm not entirely sure of that now, looking through
the changelog -- but, there seem to be a number of things mentioning
lock-break patches or fixes to general locking type stuff. If I
understand correctly the lowlatency patches were/are mainly about
breaking up locks that the kernel sometimes holds too long. (I don't
really know what any of that means ... :-\ ) I think the -mm tree has
become the official testing/holding ground (for now at least) for
patches between releases of the 2.6.x series
As far as annectdotal evidence, I'm running jack and ecasound right now
with jack started this way:
jackstart -v -R -d alsa -d ice1712 -r 44100 -p 128 -n 2
using linux 2.6.2 and alsa-drivers-1.0.2c. Seems to be working fairly
well here. no dropouts or xruns while browsing, writing this mail,
switching desktops, or switching out of X to the console.
-Eric Rz.
7:42 p.m.
Hallo,
Eric Dantan Rzewnicki hat gesagt: // Eric Dantan Rzewnicki wrote:
As far as annectdotal evidence, I'm running jack
and ecasound right now
with jack started this way:
jackstart -v -R -d alsa -d ice1712 -r 44100 -p 128 -n 2
using linux 2.6.2 and alsa-drivers-1.0.2c. Seems to be working fairly
well here. no dropouts or xruns while browsing, writing this mail,
switching desktops, or switching out of X to the console.
Some more anecdotes: I switched to 2.6 now, currently running
2.6.2-rc3 with ALSA CVS and capabilities patch. My laptop even uses
the stock Debian 2.6.0 package. System responsiveness is much improved
in general and even feels faster than my LL and preemptible patched
2.4.22 kernel (I know it isn't but it really does feel so.) On the
audio side I generally don't get any dropouts even under load.
I was switching between 2.4 and 2.6 a lot the last two weeks, and I
still cannot print in 2.6, but in general I really prefer 2.6 now.
ciao
--
Frank Barknecht _ ______footils.org__
16 Feb
16 Feb
3:27 a.m.
Hi,
On Monday 16 February 2004 00.37, Frank Barknecht wrote:
Hallo,
Eric Dantan Rzewnicki hat gesagt: // Eric Dantan Rzewnicki wrote:
It's possible 2.6 actually _is_ faster (not as in more mhz). Some of the new
features should definitely make a difference, improved threading and improved
scheduler for instance.
There was a test report posted on slashdot a few weeks ago sporting some
server apps running under both kernels. The results where quite astonishing.
I think some of the tests showed over 60% (!!!) better performance (don't ask
me how they counted, I only skimmed it).
Now, testing the kernel with respect to server performance might not have a
lot to do with audio/desktop performance but it's definitely a hint.
/Robert
As far as annectdotal evidence, I'm running
jack and ecasound right now
with jack started this way:
jackstart -v -R -d alsa -d ice1712 -r 44100 -p 128 -n 2
using linux 2.6.2 and alsa-drivers-1.0.2c. Seems to be working fairly
well here. no dropouts or xruns while browsing, writing this mail,
switching desktops, or switching out of X to the console.
Some more anecdotes: I switched to 2.6 now, currently running
2.6.2-rc3 with ALSA CVS and capabilities patch. My laptop even uses
the stock Debian 2.6.0 package. System responsiveness is much improved
in general and even feels faster than my LL and preemptible patched
2.4.22 kernel (I know it isn't but it really does feel so.) On the
audio side I generally don't get any dropouts even under load.
I was switching between 2.4 and 2.6 a lot the last two weeks, and I
still cannot print in 2.6, but in general I really prefer 2.6 now.
ciao
10:38 a.m.
That's interesting. My old pII is slated to become my web/mail/icecast
server soon. I've been toying with the idea of trying 2.6.x on it for
that. Your comments move me closer to actually doing it.
On another note ... Do you think it's possible for the 2.6.x kernel to
_sound_ better? Maybe I'm just being silly, or maybe it's because the
noisy PII box is turned off at the momemnt, but, things definitely seem
to sound better coming from my new box with the new kernel. Maybe it's
just all in my head. :)
-Eric
Robert Jonsson wrote:
It's possible 2.6 actually _is_ faster (not as in
more mhz). Some of
the new
features should definitely make a difference, improved
threading and improved
scheduler for instance.
There was a test report posted on slashdot a few weeks ago sporting some
server apps running under both kernels. The results where quite astonishing.
I think some of the tests showed over 60% (!!!) better performance (don't ask
me how they counted, I only skimmed it).
Now, testing the kernel with respect to server performance might not have a
lot to do with audio/desktop performance but it's definitely a hint.
/Robert
15 Feb
15 Feb
7:51 p.m.
Eric,
Does your jackstart command string work with "-r 96000" (and, probably, with
greater "-p") using 2.6.2?
Andrew
======= On Monday 16 February 2004 02:12, Eric Dantan Rzewnicki wrote: =======
I think much (most? all?) of the lowlatency patch set was merged into
the 2.6.1 release. I'm not entirely sure of that now, looking through
the changelog -- but, there seem to be a number of things mentioning
lock-break patches or fixes to general locking type stuff. If I
understand correctly the lowlatency patches were/are mainly about
breaking up locks that the kernel sometimes holds too long. (I don't
really know what any of that means ... :-\ ) I think the -mm tree has
become the official testing/holding ground (for now at least) for
patches between releases of the 2.6.x series
As far as annectdotal evidence, I'm running jack and ecasound right now
with jack started this way:
jackstart -v -R -d alsa -d ice1712 -r 44100 -p 128 -n 2
using linux 2.6.2 and alsa-drivers-1.0.2c. Seems to be working fairly
well here. no dropouts or xruns while browsing, writing this mail,
switching desktops, or switching out of X to the console.
-Eric Rz.
11:21 p.m.
sorry, I don't know. I've never anything other than 44100. I have had
jack running with much lower -p's, for what it's worth.
I've been running sessions of my guitar_mix scripts all night trying out
various ecasound effects. Now that I've finally moved my delta66 over to
my new athlon box I can do much more. Just mixing 5 tracks (w/panning
and amplify effects controlled by oscillators) to 3 outputs was about
all my old pII 400 could handle, so it's fun to finally have enough cpu
to play with compression, reverb, filters, etc, etc. :-D
Anyway, I had a point ... I've run into a few issues. after one
successful ecasound or ecaplay session I have to stop and restart jackd
before another ecasound will work. If I don't restart jack the next
eca(sound|play) gets stuck in a futex() ... It's bed time now, but, I'll
try to tie this down tomorrow or later this week and report it to kai
and the jack list.
I also had an issue with the new ams-1.7.3. It gets kicked out of the
jack graph if I switch windows or desktops with the openbox3
keybindings. Again, I'll investigate that more closely later this week.
-Eric Rz.
Andrew Gaydenko wrote:
Eric,
Does your jackstart command string work with "-r 96000" (and, probably, with
greater "-p") using 2.6.2?
Andrew
16 Jan
16 Jan
6:59 p.m.
Yep I have got Jack working with all versions of 2.6.x
It runs as root no problem or with jackstart with capabilities patch
applied as per jack FAQ.
Just a silly question but you have got the volumes turned up on the
mixer haven't you?
James
On Sat, Jan 17, 2004 at 08:09:43AM +1300, Glenn McCord wrote:
I've been using a 2.4.2 kernel with Andrew
Morton's patches and I got
jack to work very well. However, seeing 2.6 is the latest and greatest
I'd like to switch but am having no luck thus far.
Q. If anyone has got jack to work great with a 2.6(.1) kernel could you
share with me what version of the 2.6 kernel you used and what patches
(if any)
At the moment I'm trying a 2.6.1 with an mm4 patch but I'm getting no
sound with my soundblaster live.
I've done:
<*> Sound card support
and, under Advanced Linux Sound Architecture --->
<*> Advanced Linux Sound Architecture
<*> Sequencer support
<*> OSS API emulation
<*> OSS Mixer API
<*> OSS PCM (digital audio) API
<*> OSS Sequencer API
rebooted and install alsa-lib-1.0.1 and alsa-utils-1.0.1 as well but I
get these errors
root@upstairs glenn # aplay /usr/kde/3.2/share/sounds/pop.wav
ALSA lib pcm_hw.c:1055:(snd_pcm_hw_open) open /dev/snd/pcmC0D0p failed:
No such file or directory
aplay: main:502: audio open error: No such file or directory
and
glenn@upstairs glenn $ alsamixer
No mixer elems found
I'm at a loss but am interested at what type of kernel others are using.
I think my next best bet is to remove alsa from the kernel and install
it seperately.
Thanks
17 Jan
17 Jan
1:29 p.m.
Oops.. just read the rest of your post.. obviously this was not the
problem.
Just to let you know, I have just had a few more problems with alsa/2.6.
Turns out that module unloading for USB devices is a bit flakey.. I have
to disable this on shutdown or I get a kernel panic when my usb keyboard
is switched on.
Good luck.
James
On Fri, Jan 16, 2004 at 10:59:19PM +0000, James Stone wrote:
Yep I have got Jack working with all versions of
2.6.x
It runs as root no problem or with jackstart with capabilities patch
applied as per jack FAQ.
Just a silly question but you have got the volumes turned up on the
mixer haven't you?
James
On Sat, Jan 17, 2004 at 08:09:43AM +1300, Glenn McCord wrote:
I've been using a 2.4.2 kernel with Andrew
Morton's patches and I got
jack to work very well. However, seeing 2.6 is the latest and greatest
I'd like to switch but am having no luck thus far.
Q. If anyone has got jack to work great with a 2.6(.1) kernel could you
share with me what version of the 2.6 kernel you used and what patches
(if any)
At the moment I'm trying a 2.6.1 with an mm4 patch but I'm getting no
sound with my soundblaster live.
I've done:
<*> Sound card support
and, under Advanced Linux Sound Architecture --->
<*> Advanced Linux Sound Architecture
<*> Sequencer support
<*> OSS API emulation
<*> OSS Mixer API
<*> OSS PCM (digital audio) API
<*> OSS Sequencer API
rebooted and install alsa-lib-1.0.1 and alsa-utils-1.0.1 as well but I
get these errors
root@upstairs glenn # aplay /usr/kde/3.2/share/sounds/pop.wav
ALSA lib pcm_hw.c:1055:(snd_pcm_hw_open) open /dev/snd/pcmC0D0p failed:
No such file or directory
aplay: main:502: audio open error: No such file or directory
and
glenn@upstairs glenn $ alsamixer
No mixer elems found
I'm at a loss but am interested at what type of kernel others are using.
I think my next best bet is to remove alsa from the kernel and install
it seperately.
Thanks
From
linux-audio-user-bounces(a)music.columbia.edu Sat Jan 17 07:38:38 2004
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Date: Sat, 17 Jan 2004 02:16:22 +0100
From: mik <mprims(a)skynet.be>
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Subject: Re: [linux-audio-user] [ANN] Visecas 0.3.1
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On Fri, 16 Jan 2004 18:27:27 +0100
Jan Weil <Jan.Weil(a)web.de> wrote:
So you could do me a favour and edit
lib/visecas/ecasound.rb by hand
instead.
Increase the TIMEOUT constant (line 76) and try if that changes your
situation.
that did the trick. thanks.
m
----> http://www.mprims.tk 
3:58 p.m.
Linux angry-boomer 2.4.23-aa1 #5 Sun Jan 4 13:01:01 EST 2004 i686 AMD
Athlon(tm) XP 2200+ AuthenticAMD GNU/Linux
the distro is Gentoo. the kernel contains Andrea Arcangeli's patches. A
description is here:
http://www.gentoo.org/doc/en/gentoo-kernel.xml
-lee
On Sat, 17 Jan 2004, Glenn McCord wrote:
I've been using a 2.4.2 kernel with Andrew
Morton's patches and I got
jack to work very well. However, seeing 2.6 is the latest and greatest
I'd like to switch but am having no luck thus far.
Q. If anyone has got jack to work great with a 2.6(.1) kernel could you
share with me what version of the 2.6 kernel you used and what patches
(if any)
At the moment I'm trying a 2.6.1 with an mm4 patch but I'm getting no
sound with my soundblaster live.
I've done:
<*> Sound card support
and, under Advanced Linux Sound Architecture --->
<*> Advanced Linux Sound Architecture
<*> Sequencer support
<*> OSS API emulation
<*> OSS Mixer API
<*> OSS PCM (digital audio) API
<*> OSS Sequencer API
rebooted and install alsa-lib-1.0.1 and alsa-utils-1.0.1 as well but I
get these errors
root@upstairs glenn # aplay /usr/kde/3.2/share/sounds/pop.wav
ALSA lib pcm_hw.c:1055:(snd_pcm_hw_open) open /dev/snd/pcmC0D0p failed:
No such file or directory
aplay: main:502: audio open error: No such file or directory
and
glenn@upstairs glenn $ alsamixer
No mixer elems found
I'm at a loss but am interested at what type of kernel others are using.
I think my next best bet is to remove alsa from the kernel and install
it seperately.
Thanks
8:23 p.m.
Interesting.
I think you will find the question was about 2.6 tho..
James
On Sat, Jan 17, 2004 at 02:40:21PM -0500, lee(a)fallingforward.net wrote:
Linux angry-boomer 2.4.23-aa1 #5 Sun Jan 4 13:01:01
EST 2004 i686 AMD
Athlon(tm) XP 2200+ AuthenticAMD GNU/Linux
the distro is Gentoo. the kernel contains Andrea Arcangeli's patches. A
description is here:
http://www.gentoo.org/doc/en/gentoo-kernel.xml
-lee
On Sat, 17 Jan 2004, Glenn McCord wrote:
> I've been using a 2.4.2 kernel with Andrew Morton's patches and I got
> jack to work very well. However, seeing 2.6 is the latest and greatest
> I'd like to switch but am having no luck thus far.
>
> Q. If anyone has got jack to work great with a 2.6(.1) kernel could you
> share with me what version of the 2.6 kernel you used and what patches
> (if any)
>
> At the moment I'm trying a 2.6.1 with an mm4 patch but I'm getting no
> sound with my soundblaster live.
> I've done:
> <*> Sound card support
>
> and, under Advanced Linux Sound Architecture --->
>
> <*> Advanced Linux Sound Architecture
> <*> Sequencer support
> <*> OSS API emulation
> <*> OSS Mixer API
> <*> OSS PCM (digital audio) API
> <*> OSS Sequencer API
>
> rebooted and install alsa-lib-1.0.1 and alsa-utils-1.0.1 as well but I
> get these errors
>
> root@upstairs glenn # aplay /usr/kde/3.2/share/sounds/pop.wav
> ALSA lib pcm_hw.c:1055:(snd_pcm_hw_open) open /dev/snd/pcmC0D0p failed:
> No such file or directory
> aplay: main:502: audio open error: No such file or directory
>
> and
>
> glenn@upstairs glenn $ alsamixer
> No mixer elems found
>
> I'm at a loss but am interested at what type of kernel others are using.
> I think my next best bet is to remove alsa from the kernel and install
> it seperately.
>
> Thanks
>
>
18 Jan
18 Jan
6:20 a.m.
That link is useful. I've been trying to find out what the mm stood for.
And I have sound working now. As it turns out I think I needed to
compile in not only:
<*> EMU10K1 (SB Live! & Audigy, E-mu APS)
but...
<*> (Creative) Ensoniq AudioPCI 1370
<*> (Creative) Ensoniq AudioPCI 1371/1373
aswell.
Now I'm off to get jack running but I've had really bad form with that
and the 2.6
Q. With the 2.4 kernel, low-latency was seen to be working by going:
cat /proc/sys/kernel/lowlatency
but now all I get is:
root@upstairs linux # cat /proc/sys/kernel/lowlatency
cat: /proc/sys/kernel/lowlatency: No such file or directory
How does the 2.6 use low-latency audio? Is it buried deep amongst the
features now, and working by default?
Thanks.
James Stone wrote:
Interesting.
I think you will find the question was about 2.6 tho..
James
On Sat, Jan 17, 2004 at 02:40:21PM -0500, lee(a)fallingforward.net wrote:
Linux angry-boomer 2.4.23-aa1 #5 Sun Jan 4
13:01:01 EST 2004 i686 AMD
Athlon(tm) XP 2200+ AuthenticAMD GNU/Linux
the distro is Gentoo. the kernel contains Andrea Arcangeli's patches. A
description is here:
http://www.gentoo.org/doc/en/gentoo-kernel.xml
-lee
On Sat, 17 Jan 2004, Glenn McCord wrote:
>I've been using a 2.4.2 kernel with Andrew Morton's patches and I got
>jack to work very well. However, seeing 2.6 is the latest and greatest
>I'd like to switch but am having no luck thus far.
>
>Q. If anyone has got jack to work great with a 2.6(.1) kernel could you
>share with me what version of the 2.6 kernel you used and what patches
>(if any)
>
>At the moment I'm trying a 2.6.1 with an mm4 patch but I'm getting no
>sound with my soundblaster live.
>I've done:
> <*> Sound card support
>
>and, under Advanced Linux Sound Architecture --->
>
> <*> Advanced Linux Sound Architecture
> <*> Sequencer support
> <*> OSS API emulation
> <*> OSS Mixer API
> <*> OSS PCM (digital audio) API
> <*> OSS Sequencer API
>
>rebooted and install alsa-lib-1.0.1 and alsa-utils-1.0.1 as well but I
>get these errors
>
>root@upstairs glenn # aplay /usr/kde/3.2/share/sounds/pop.wav
>ALSA lib pcm_hw.c:1055:(snd_pcm_hw_open) open /dev/snd/pcmC0D0p failed:
>No such file or directory
>aplay: main:502: audio open error: No such file or directory
>
>and
>
>glenn@upstairs glenn $ alsamixer
>No mixer elems found
>
>I'm at a loss but am interested at what type of kernel others are using.
>I think my next best bet is to remove alsa from the kernel and install
>it seperately.
>
>Thanks
>
>
>
>
7 a.m.
On Sun, Jan 18, 2004 at 11:20:32PM +0000, Glenn McCord wrote:
That link is useful. I've been trying to find out
what the mm stood for.
And I have sound working now. As it turns out I think I needed to
compile in not only:
<*> EMU10K1 (SB Live! & Audigy, E-mu APS)
but...
<*> (Creative) Ensoniq AudioPCI 1370
<*> (Creative) Ensoniq AudioPCI 1371/1373
aswell.
Interesting. What sound card do you have?
Now I'm off to get jack running but I've had really bad form with that
and the 2.6
What problems?
Q. With the 2.4 kernel, low-latency was seen to be working by going:
cat /proc/sys/kernel/lowlatency
but now all I get is:
root@upstairs linux # cat /proc/sys/kernel/lowlatency
cat: /proc/sys/kernel/lowlatency: No such file or directory
How does the 2.6 use low-latency audio? Is it buried deep amongst the
features now, and working by default?
As I understand it, low latency features are included in the kernel and
you don't need to do anything extra.
James
9:55 p.m.
I'm having no luck getting low latency with a 2.6 kernel.
I'm using the mm4 patches and have modified the capabilities.h file.
I have this entered into fstab:
shmfs /dev/shm shm defaults 0 0
none /dev/shm tmpfs defaults 0 0
none /tmp/jack tmpfs defaults 0 0
none /mnt/ramfs tmpfs defaults 0 0
and compiled jack with:
./configure --with-default-tmpdir=/mnt/ramfs --enable-capabilities
--enable-realtime
I want to use ardour so that was just a staight ./configure && make
To run jack I go
jackstart -R -v -d alsa -d hw:0 -p 8192
My problem is that I get
**** alsa_pcm: xrun of at least xx.xxx msecs
all the time. I even get it when no audio programs are going.
On the 2.4.2 I can get jack to run with no -p options at all and it runs
perfectly, hence my anguish.
Cheers for any help. This is pretty much all the stuff I've done so
throw me ANY hints.
James Stone wrote:
On Sun, Jan 18, 2004 at 11:20:32PM +0000, Glenn McCord
wrote:
I have a soundblaster Live but this problem may have arisen from copy
and pasting .config files from 2.6 to 2.6.1-mm4 to 2.6.1, so something
probably came unstuck.
That link is useful. I've been trying to find
out what the mm stood for.
And I have sound working now. As it turns out I think I needed to
compile in not only:
<*> EMU10K1 (SB Live! & Audigy, E-mu APS)
but...
<*> (Creative) Ensoniq AudioPCI 1370
<*> (Creative) Ensoniq AudioPCI 1371/1373
aswell.
Interesting. What sound card do you have?
Now I'm off to get jack running but I've
had really bad form with that
and the 2.6
What problems?
Q. With the 2.4 kernel, low-latency was seen to be
working by going:
cat /proc/sys/kernel/lowlatency
but now all I get is:
root@upstairs linux # cat /proc/sys/kernel/lowlatency
cat: /proc/sys/kernel/lowlatency: No such file or directory
How does the 2.6 use low-latency audio? Is it buried deep amongst the
features now, and working by default?
As I understand it, low latency features are included in the kernel and
you don't need to do anything extra.
James
19 Jan
19 Jan
3:36 a.m.
On Mon, Jan 19, 2004 at 02:51:13PM +1300, Glenn McCord wrote:
I'm having no luck getting low latency with a 2.6
kernel.
I'm using the mm4 patches and have modified the capabilities.h file.
I have this entered into fstab:
shmfs /dev/shm shm defaults 0 0
none /dev/shm tmpfs defaults 0 0
none /tmp/jack tmpfs defaults 0 0
none /mnt/ramfs tmpfs defaults 0 0
and compiled jack with:
./configure --with-default-tmpdir=/mnt/ramfs --enable-capabilities
--enable-realtime
I want to use ardour so that was just a staight ./configure && make
To run jack I go
jackstart -R -v -d alsa -d hw:0 -p 8192
My problem is that I get
**** alsa_pcm: xrun of at least xx.xxx msecs
all the time. I even get it when no audio programs are going.
AFAIK you have got your soundcard set up wrong. I have a SBLive and did
not need any modules apart from the snd_emu10k1 one. I do get a few
xruns when moving windows and switching between apps but that is with -p
512. I am also using the realtime LSM module rather than the hand edit
option but I don't think that is your problem.
What are the alsa bits in your /lib/modules/modprobe.conf (or
/etc/modprobe.conf)?
James
5:45 a.m.
my /etc/modprobe.conf has these entries
alias snd-card-0 snd-emu10k1
alias sound-service-0-0 snd-mixer-oss
alias sound-service-0-1 snd-seq-oss
alias sound-service-0-3 snd-pcm-oss
alias sound-service-0-8 snd-seq-oss
alias sound-service-0-12 snd-pcm-oss
alias /dev/mixer snd-mixer-oss
alias /dev/dsp snd-pcm-oss
alias /dev/midi snd-seq-oss
But surely the 2.6 should work as good as my 2.4 kernel where I had
absolutely no xruns at any time?
James Stone wrote:
On Mon, Jan 19, 2004 at 02:51:13PM +1300, Glenn McCord
wrote:
Yeah, I think I slipped up somewhere when copying .config files between
different 2.6 kernels and I just drew a conclusion which was wrong.
I'm having no luck getting low latency with a
2.6 kernel.
I'm using the mm4 patches and have modified the capabilities.h file.
I have this entered into fstab:
shmfs /dev/shm shm defaults 0 0
none /dev/shm tmpfs defaults 0 0
none /tmp/jack tmpfs defaults 0 0
none /mnt/ramfs tmpfs defaults 0 0
and compiled jack with:
./configure --with-default-tmpdir=/mnt/ramfs --enable-capabilities
--enable-realtime
I want to use ardour so that was just a staight ./configure && make
To run jack I go
jackstart -R -v -d alsa -d hw:0 -p 8192
My problem is that I get
**** alsa_pcm: xrun of at least xx.xxx msecs
all the time. I even get it when no audio programs are going.
AFAIK you have got your soundcard set up wrong. I have a SBLive and did
not need any modules apart from the snd_emu10k1 one. I do get a few
xruns when moving windows and switching between apps but that is with -p
512. I am also using the realtime LSM module rather than the hand edit
option but I don't think that is your problem.
What are the alsa bits in your /lib/modules/modprobe.conf (or
/etc/modprobe.conf)?
James
2:32 p.m.
On Mon, Jan 19, 2004 at 10:44:50PM +0000, Glenn McCord wrote:
my /etc/modprobe.conf has these entries
alias snd-card-0 snd-emu10k1
alias sound-service-0-0 snd-mixer-oss
alias sound-service-0-1 snd-seq-oss
alias sound-service-0-3 snd-pcm-oss
alias sound-service-0-8 snd-seq-oss
alias sound-service-0-12 snd-pcm-oss
alias /dev/mixer snd-mixer-oss
alias /dev/dsp snd-pcm-oss
alias /dev/midi snd-seq-oss
I think that looks fine.. but where are those other alsa modules that
you were referring to?
James
4:10 a.m.
Just had a few more thoughts...
On Mon, Jan 19, 2004 at 02:51:13PM +1300, Glenn McCord wrote:
I'm having no luck getting low latency with a 2.6
kernel.
I'm using the mm4 patches and have modified the capabilities.h file.
I have this entered into fstab:
shmfs /dev/shm shm defaults 0 0
none /dev/shm tmpfs defaults 0 0
none /tmp/jack tmpfs defaults 0 0
none /mnt/ramfs tmpfs defaults 0 0
and compiled jack with:
./configure --with-default-tmpdir=/mnt/ramfs --enable-capabilities
--enable-realtime
Not sure but don't think you need --enable-realtime.
Also, You have installed the new modutils? You have compiled preemptive
kernel and rtc support into the kernel? You have compiled support for
your motherboard's chipset into the kernel?
James
5:54 a.m.
Once upon a Mon, Jan 19 2004, James Stone hit keys in the following order:
I am, you need it.
Just had a few more thoughts...
On Mon, Jan 19, 2004 at 02:51:13PM +1300, Glenn McCord wrote:
> I'm having no luck getting low latency with a 2.6 kernel.
> I'm using the mm4 patches and have modified the capabilities.h file.
You don't need to modify the capabilities header any more. Try using
http://www.joq.us/realtime/ for realtime capabilities, it works great.
./configure
--with-default-tmpdir=/mnt/ramfs --enable-capabilities
--enable-realtime
Not sure but don't think you need --enable-realtime. Also, You have installed the new modutils? You have
compiled preemptive
kernel and rtc support into the kernel? You have compiled support for
your motherboard's chipset into the kernel?
and be sure that you didn't include those as modules. i did and my udma wasn't
activated because of that (and couldn't, until i loaded the module manually of
course).
success.
martijn.
2:24 p.m.
./configure --with-default-tmpdir=/mnt/ramfs
--enable-capabilities
--enable-realtime
Not sure but don't think you need --enable-realtime. 
4:04 p.m.
On Mon, Jan 19, 2004 at 06:24:34PM +0000, James Stone wrote:
I am, you need it.
I had never heard of that option until this email: if you do a
./configure --help in the jack source directory it isn't mentioned, also
it is not mentioned on the jack site. I have tried to compile with this
option and it doesn't seem to make any difference.. I can run jack with
the -R option either way. What effect is it supposed to have? Or is it
enabled by default?
Yes, there is no --enable-realtime option:
$ grep AC_ARG_ENABLE.*realtime configure.in
$
- Steve
./configure
--with-default-tmpdir=/mnt/ramfs --enable-capabilities
--enable-realtime
Not sure but don't think you need --enable-realtime. 
4:34 p.m.
James Stone <stone1(a)btinternet.com> writes:
I am, you need it.
I had never heard of that option until this email: if you do a
./configure --help in the jack source directory it isn't mentioned, also
it is not mentioned on the jack site. I have tried to compile with this
option and it doesn't seem to make any difference.. I can run jack with
the -R option either way. What effect is it supposed to have? Or is it
enabled by default?
You are correct. JACK's ./configure has no --enable-realtime option.
Martijn probably means the --realtime option of jackd (same as -R).
As you know, you *do* need that. ;-)
--
joq
./configure
--with-default-tmpdir=/mnt/ramfs --enable-capabilities
--enable-realtime
Not sure but don't think you need --enable-realtime.
7:49 p.m.
New subject: [linux-audio-user] Which kernel for low latency and kernel 2.6.1-mm# problems
Once upon a Mon, Jan 19 2004, Jack O'Quin hit keys in the following order:
You are correct. JACK's ./configure has no --enable-realtime option.
Martijn probably means the --realtime option of jackd (same as -R).
True. I was thinking of --enable-capabilities and the realtime security module
and something mixed up in my brain.
something else, has anyone got 2.6.1 with a version of Andrew Morton's patch
branch working? I wanted to upgrade to alsa 1.0.1 and that seemed to be the
easiest way, but the first buffer that get's filled starts looping until i
close the soundcard programmatically. like if there's an interrupt conflict or
something... I have an Audiophile 2496 (ice1712) on an Asus a7v333-x. o and i'm
totally sure there's no interrupt conflict in my system. Everything works fine
with an unpatched 2.6.1 though... Has anyone with the same hardware/kernel
combo got this to work?
martijn.
20 Jan
20 Jan
3:51 a.m.
New subject: [linux-audio-user] Which kernel for low latency and kernel 2.6.1-mm# problems
On Tue, Jan 20, 2004 at 12:45:06AM +0100, martijn wrote:
Once upon a Mon, Jan 19 2004, Jack O'Quin hit keys
in the following order:
Yep I am running 2.6.1mm4 but with a SBLive. The only problems I had were
related to running the kernel modules with the old version of alsa
libraries.
(Oh apart from some kernel panics which occurred when the computer tried
to remove snd_usb_audio at shutdown when my usb midi keyboard was on..
had to change the shutdown script to solve that one..)
Doesn't the a7v333-x have an Nforce chipset or some such? I think there
are problems with this chipset at the moment.
I must say that though 2.6.1 is very nice, it does seem a little buggy
for a stable release.
James
You are correct. JACK's ./configure has no --enable-realtime option.
Martijn probably means the --realtime option of jackd (same as -R).
True. I was thinking of --enable-capabilities and the realtime security module
and something mixed up in my brain.
something else, has anyone got 2.6.1 with a version of Andrew Morton's patch
branch working? I wanted to upgrade to alsa 1.0.1 and that seemed to be the
easiest way, but the first buffer that get's filled starts looping until i
close the soundcard programmatically. like if there's an interrupt conflict or
something... I have an Audiophile 2496 (ice1712) on an Asus a7v333-x. o and i'm
totally sure there's no interrupt conflict in my system. Everything works fine
with an unpatched 2.6.1 though... Has anyone with the same hardware/kernel
combo got this to work?
martijn.
6:12 a.m.
New subject: [linux-audio-user] kernel 2.6.1-mm# problems
Once upon a Tue, Jan 20 2004, James Stone hit keys in the following order:
Yep I am running 2.6.1mm4 but with a SBLive. The only problems I had were
related to running the kernel modules with the old version of alsa
libraries.
I run the correct library version, that's not the problem.
Doesn't the a7v333-x have an Nforce chipset or
some such? I think there
are problems with this chipset at the moment.
No, its has the VIA chipset. hmm i'll try and see if the onboard audio works
better. Back to the bios.
I must say that though 2.6.1 is very nice, it does
seem a little buggy
for a stable release.
is that due to the kernel? for what use is it buggy? i must admit i've been
more busy with updates then actually be productive with audio tools, but it
seems very stable to me.
martijn
6:14 a.m.
New subject: [linux-audio-user] Which kernel for low latency and kernel 2.6.1-mm# problems
I adjusted some things. For me the realtime patch didn't work so I
reverted back to modifying capabilities.h by hand.
<*> EMU10K1 (SB Live! & Audigy, E-mu APS) is now the only audio PCI
device selcted.
I also double-checked to make sure
CONFIG_PREEMPT (Processor tyoe and features -> Preemptibel Kernel)
CONFIG_RTC (Character Devices -> Enhanced Real Time Clock)
CONFIG_SND_RTCTIMER (Sound -> Advanced Linux Sound Architecture -> RTC
Timer support)
were built in.
I then install alsa-lib and alsa-utils 1.0.1 using the gentoo ebuilds.
I compiled jack from source with:
./configure --enable-optimize --with-gnu-ld --enable-capabilities
--enable-stripped-jackd --with-default-tmpdir=/mnt/ramfs
I run jack with:
jackstart -R -v -d alsa -d hw:0
...and I get xruns whenever I open a program, move windows around. Hell
sometimes it does it when I'm just looking at it. More specifically, if
I want to record in ardour, jack chokes up an xrun after about 2 seconds.
Now, if I whip up my 2.4.2 with Andrew Morton's Low latency patch,
install alsa-lib, alsa-driver and alsa-utils version 1.0.1with the
gentoo ebuilds, then compile jack like above... presto, no problems.
So I'm thinking somethings missing in the kernel somewhere. Or perhaps
the system settings are disagreeing with the way the kernel is setup.
Someone mentioned the /etc/modules.conf and the /etc/modprobe.conf so I
attached it to the email in case there is something damning there that
I've missed.
Also, does anyone use an ~/asoundrc or /etc/asound.conf file? I don't
have one. I used to, but it's... disappeared...
Thanks.
James Stone wrote:
On Tue, Jan 20, 2004 at 12:45:06AM +0100, martijn
wrote:
Once upon a Mon, Jan 19 2004, Jack O'Quin hit
keys in the following order:
Yep I am running 2.6.1mm4 but with a SBLive. The only problems I had were
related to running the kernel modules with the old version of alsa
libraries.
(Oh apart from some kernel panics which occurred when the computer tried
to remove snd_usb_audio at shutdown when my usb midi keyboard was on..
had to change the shutdown script to solve that one..)
Doesn't the a7v333-x have an Nforce chipset or some such? I think there
are problems with this chipset at the moment.
I must say that though 2.6.1 is very nice, it does seem a little buggy
for a stable release.
James
You are correct. JACK's ./configure has no
--enable-realtime option.
Martijn probably means the --realtime option of jackd (same as -R).
True. I was thinking of --enable-capabilities and the realtime security module
and something mixed up in my brain.
something else, has anyone got 2.6.1 with a version of Andrew Morton's patch
branch working? I wanted to upgrade to alsa 1.0.1 and that seemed to be the
easiest way, but the first buffer that get's filled starts looping until i
close the soundcard programmatically. like if there's an interrupt conflict or
something... I have an Audiophile 2496 (ice1712) on an Asus a7v333-x. o and i'm
totally sure there's no interrupt conflict in my system. Everything works fine
with an unpatched 2.6.1 though... Has anyone with the same hardware/kernel
combo got this to work?
martijn.
7:51 a.m.
New subject: [linux-audio-user] Which kernel for low latency and kernel 2.6.1-mm# problems
--- Glenn McCord <clari_player(a)paradise.net.nz> wrote:
<SNIP>
<*> EMU10K1 (SB Live! & Audigy, E-mu APS) is now the only audio PCI
device selcted.
<SNIP>>
Also, does anyone use an ~/asoundrc or /etc/asound.conf file?
I don't have one. I used to, but it's... disappeared...
i just use the one from the alsa website. its listed on the SBLive
page:
http://www.alsa-project.org/alsa-doc/doc-php/template.php?company=Creative+…
ALEX
________________________________________________________________________
Yahoo! Messenger - Communicate instantly..."Ping"
your friends today! Download Messenger Now
http://uk.messenger.yahoo.com/download/index.html
9:56 a.m.
New subject: [linux-audio-user] Which kernel for low latency
Once upon a Tue, Jan 20 2004, Glenn McCord hit keys in the following order:
I adjusted some things. For me the realtime patch
didn't work so I
reverted back to modifying capabilities.h by hand.
Realtime patch? i assume you mean the realtime LSM from www.joq.us. You build
it separately, although you do need to set KERNEL_DIR to your kernel-2.6.x
sources because it uses the kernel's build system. Where does it fail? Also,
make shure you add 'options realtime allcaps=1' to your /etc/modprobe.conf,
otherwise it will not work with jackstart.
Just interested, how did you modify capability.h? i couldn't get it to compile
when i tried that.
So I'm thinking somethings missing in the kernel
somewhere. Or perhaps
the system settings are disagreeing with the way the kernel is setup.
I had problems too and discovered that i was compiling my IDE chipset support
as a module that never got loaded. No UDMA is a bad thing for performance. You
can check it with something like 'hdparm -d /dev/hda'.
mrtn.
11:11 p.m.
New subject: [linux-audio-user] Which kernel for low latency
martijn wrote:
# hdparm -d /dev/hda
/dev/hda:
using_dma = 1 (on)
I'm assuming this is what I'm supposed to get.
xruns happen when I open ardour, create a track, remove tracks and
whenever I record for anything longer than a couple of seconds. I was
able to record for 20 seconds just before, but that's because I was lucky.
I noticed that the cpu load indicator in ardour fluctuates all over the
show. After an xrun it jumps from below 10% to about 30-50%. With the
2.4 it never rises above 3%. I may just have to nag the ardour mailing
list instead.
rezound gives the same strife. xruns occur when dialogue boxes open and
after recording for a few seconds.
I feel like I'm going in circles now so I may just have to revisit it in
6 months or something.
Thanks for all the help though.
Once upon a Tue, Jan 20 2004, Glenn McCord hit keys in
the following order:
It fails when I try and run jackstart and i gives this error:
glenn@upstairs glenn $ jackstart -R -v -d alsa -d hw:0
jackstart: cannot get realtime capabilities, current capabilities are:
=ep cap_setpcap-ep
probably running under a kernel with capabilities disabled,
a suitable kernel would have printed something like "=eip"
I modified modprobe.conf but it's ignored. When I restart the machine
the line I added disappears anyway when it does an update-modules.
modprobe.conf has a comment saying I should modify modules.conf instead
but that doesn't do any good either.
Here's the error that comes up:
I adjusted some things. For me the realtime patch
didn't work so I
reverted back to modifying capabilities.h by hand.
Realtime patch? i assume you mean the realtime LSM from www.joq.us. You build
it separately, although you do need to set KERNEL_DIR to your kernel-2.6.x
sources because it uses the kernel's build system. Where does it fail? Also,
make shure you add 'options realtime allcaps=1' to your /etc/modprobe.conf,
otherwise it will not work with jackstart.
Just interested, how did you modify capability.h? i couldn't get it to compile
when i tried that.
replace
#define CAP_INIT_EFF_SET to_cap_t(~0 & ~CAP_TO_MASK(CAP_SETPCAP))
with
#define CAP_INIT_EFF_SET to_cap_t(~0)
Below this line, there should be another line that should looks like:
#define CAP_INIT_INH_SET to_cap_t(0)
so replace it with
#define CAP_INIT_INH_SET to_cap_t(~0)
So I'm thinking somethings missing in the
kernel somewhere. Or perhaps
the system settings are disagreeing with the way the kernel is setup.
I had problems too and discovered that i was compiling my IDE chipset support
as a module that never got loaded. No UDMA is a bad thing for performance. You
can check it with something like 'hdparm -d /dev/hda'.
mrtn.
11:37 p.m.
New subject: [linux-audio-user] Which kernel for low latency
Glenn McCord <clari_player(a)paradise.net.nz> writes:
It fails when I try and run jackstart and i gives this
error:
glenn@upstairs glenn $ jackstart -R -v -d alsa -d hw:0
jackstart: cannot get realtime capabilities, current capabilities are:
=ep cap_setpcap-ep
probably running under a kernel with capabilities disabled,
a suitable kernel would have printed something like "=eip"
I modified modprobe.conf but it's ignored. When I restart the machine
the line I added disappears anyway when it does an
update-modules. modprobe.conf has a comment saying I should modify
modules.conf instead but that doesn't do any good either.
What parameters did you pass the realtime LSM on modprobe?
What did it say when you ran `modprobe realtime ...'?
What /var/log/messages did you get after the modprobe?
--
joq
21 Jan
21 Jan
2:45 p.m.
New subject: [linux-audio-user] Which kernel for low latency
Once upon a Wed, Jan 21 2004, Glenn McCord hit keys in the following order:
I modified modprobe.conf but it's ignored. When I restart the machine
the line I added disappears anyway when it does an update-modules.
modprobe.conf has a comment saying I should modify modules.conf instead
but that doesn't do any good either.
Ahhh, got confused again, what is it with me and january. modules.conf is
indeed the place to add the option. modprobe.conf is the one thats used by
modprobe but it's the output from generate-modprobe.conf, hence my confusion.
The command "modprobe realtime allcaps=1" is another way to supply the option.
replace
#define CAP_INIT_EFF_SET to_cap_t(~0 & ~CAP_TO_MASK(CAP_SETPCAP))
with
#define CAP_INIT_EFF_SET to_cap_t(~0)
Below this line, there should be another line that should looks like:
#define CAP_INIT_INH_SET to_cap_t(0)
so replace it with
#define CAP_INIT_INH_SET to_cap_t(~0)
Weird, i did the same thing, but it didn't work for me, if i remember
correctly. But then again, maybe my problem was that it compiled but didn't
actually give me any realtime priority. Like you describe i had continues
x-runs in the beginning. Now the only time i get x-runs is when an idle program
gets pulled back in focus, or when there's a lot of network activity.
martijn.
6:10 p.m.
New subject: [linux-audio-user] Which kernel for low latency
x-runs in the beginning. Now the only time i get
x-runs is when an idle program
gets pulled back in focus, or when there's a lot of network activity.
Ahh.. but this doesn't happen in 2.4.23 (or at least in my experience).
James.
10:38 p.m.
New subject: [linux-audio-user] Which kernel for low latency
martijn wrote:
Once upon a Wed, Jan 21 2004, Glenn McCord hit keys in
the following order:
Okay, it's all good now. I'd compiled the kernel again (from scratch)
and forgot to put in the security options in.
thanks.
I modified modprobe.conf but it's ignored.
When I restart the machine
the line I added disappears anyway when it does an update-modules.
modprobe.conf has a comment saying I should modify modules.conf instead
but that doesn't do any good either.
Ahhh, got confused again, what is it with me and january. modules.conf is
indeed the place to add the option. modprobe.conf is the one thats used by
modprobe but it's the output from generate-modprobe.conf, hence my confusion.
The command "modprobe realtime allcaps=1" is another way to supply the option.
replace
#define CAP_INIT_EFF_SET to_cap_t(~0 & ~CAP_TO_MASK(CAP_SETPCAP))
with
#define CAP_INIT_EFF_SET to_cap_t(~0)
Below this line, there should be another line that should looks like:
#define CAP_INIT_INH_SET to_cap_t(0)
so replace it with
#define CAP_INIT_INH_SET to_cap_t(~0)
Weird, i did the same thing, but it didn't work for me, if i remember
correctly. But then again, maybe my problem was that it compiled but didn't
actually give me any realtime priority. Like you describe i had continues
x-runs in the beginning. Now the only time i get x-runs is when an idle program
gets pulled back in focus, or when there's a lot of network activity.
martijn.
20 Jan
20 Jan
12:38 p.m.
New subject: [linux-audio-user] Which kernel for low latency and kernel 2.6.1-mm# problems
Glenn McCord <clari_player(a)paradise.net.nz> writes:
I adjusted some things. For me the realtime patch
didn't work so I
reverted back to modifying capabilities.h by hand.
Is this the realtime LSM? What happened when you tried to build it?
Were you able to load the module with modprobe?
--
joq
6:24 p.m.
New subject: [linux-audio-user] Which kernel for low latency and kernel 2.6.1-mm# problems
I run jack with:
jackstart -R -v -d alsa -d hw:0
...and I get xruns whenever I open a program, move windows around. Hell
sometimes it does it when I'm just looking at it. More specifically, if
I want to record in ardour, jack chokes up an xrun after about 2 seconds.
Now, if I whip up my 2.4.2 with Andrew Morton's Low latency patch,
install alsa-lib, alsa-driver and alsa-utils version 1.0.1with the
gentoo ebuilds, then compile jack like above... presto, no problems.
So I'm thinking somethings missing in the kernel somewhere. Or perhaps
the system settings are disagreeing with the way the kernel is setup.
Ah.. I have just tried 2.4.23 with the low latency patch again.. and I
agree.. Jack is much more stable. I am not sure I was getting as many
xruns as you, but in 2.4.23 I am getting absolutely none, even being
quite rough with opening and closing things.. Even running kernel
compile in the background!
This paired with the kernel panics I was getting on shutdown makes me
think that 2.6.x is not quite ready for audio yet.
James
10:44 p.m.
New subject: [linux-audio-user] Which kernel for low latency and kernel 2.6.1-mm# problems
James Stone wrote:
phew, it's good to see I'm not the only one.
I run jack
with:
jackstart -R -v -d alsa -d hw:0
...and I get xruns whenever I open a program, move windows around. Hell
sometimes it does it when I'm just looking at it. More specifically, if
I want to record in ardour, jack chokes up an xrun after about 2 seconds.
Now, if I whip up my 2.4.2 with Andrew Morton's Low latency patch,
install alsa-lib, alsa-driver and alsa-utils version 1.0.1with the
gentoo ebuilds, then compile jack like above... presto, no problems.
So I'm thinking somethings missing in the kernel somewhere. Or perhaps
the system settings are disagreeing with the way the kernel is setup.
Ah.. I have just tried 2.4.23 with the low latency patch again.. and I
agree.. Jack is much more stable. I am not sure I was getting as many
xruns as you, but in 2.4.23 I am getting absolutely none, even being
quite rough with opening and closing things.. Even running kernel
compile in the background!
This paired with the kernel panics I was getting on shutdown makes me
think that 2.6.x is not quite ready for audio yet.
James
21 Jan
21 Jan
6:12 a.m.
New subject: [linux-audio-user] Which kernel for low latency and kernel 2.6.1-mm# problems
Hi,
It seems we have quite a few reports of 2.6 working badly with realtime
scheduling.
I haven't tried 2.6 myself yet, but, I would say there are problems that we
need to find and eliminate. (Still, it could be configuration issues, but we
need to find these too.) Last I heard Andrew (cc:ed) thought it worked as
good as 2.4, except for some rare corner cases.
Now, how do we proceed, are there any evidence that we can forward to the
kernel folks?
Regards,
Robert
On Wednesday 21 January 2004 03.38, Glenn McCord wrote:
James Stone wrote:
phew, it's good to see I'm not the only one.
>This paired with the kernel panics I was getting on shutdown makes me
>think that 2.6.x is not quite ready for audio yet.
>
>James
I run jack
with:
jackstart -R -v -d alsa -d hw:0
...and I get xruns whenever I open a program, move windows around. Hell
sometimes it does it when I'm just looking at it. More specifically, if
I want to record in ardour, jack chokes up an xrun after about 2 seconds.
Now, if I whip up my 2.4.2 with Andrew Morton's Low latency patch,
install alsa-lib, alsa-driver and alsa-utils version 1.0.1with the
gentoo ebuilds, then compile jack like above... presto, no problems.
So I'm thinking somethings missing in the kernel somewhere. Or perhaps
the system settings are disagreeing with the way the kernel is setup.
Ah.. I have just tried 2.4.23 with the low latency patch again.. and I
agree.. Jack is much more stable. I am not sure I was getting as many
xruns as you, but in 2.4.23 I am getting absolutely none, even being
quite rough with opening and closing things.. Even running kernel
compile in the background! 
6:23 a.m.
New subject: [linux-audio-user] Which kernel for low latency and kernel 2.6.1-mm# problems
Robert Jonsson <robert.jonsson(a)dataductus.se> wrote:
Hi,
It seems we have quite a few reports of 2.6 working badly with realtime
scheduling.
I haven't tried 2.6 myself yet, but, I would say there are problems that we
need to find and eliminate. (Still, it could be configuration issues, but we
need to find these too.) Last I heard Andrew (cc:ed) thought it worked as
good as 2.4, except for some rare corner cases.
Not as rare as one would like. But not too bad unless you're doing heavy
filesytem work at the same time.
On Wednesday 21 January 2004 03.38, Glenn McCord
wrote:
> James Stone wrote:
> >>I run jack with:
> >>jackstart -R -v -d alsa -d hw:0
> >>
> >>...and I get xruns whenever I open a program, move windows around. Hell
> >>sometimes it does it when I'm just looking at it. More specifically, if
> >>I want to record in ardour, jack chokes up an xrun after about 2 seconds.
> >>
Is `jack' running with realtime priority, or is it merely SCHED_OTHER?
6:41 a.m.
New subject: [linux-audio-user] Which kernel for low latency and kernel 2.6.1-mm# problems
On Wed, Jan 21, 2004 at 02:20:04AM -0800, Andrew Morton wrote:
Its running SCHED_FIFO in this case.
- Steve
need to find
these too.) Last I heard Andrew (cc:ed) thought it worked as
good as 2.4, except for some rare corner cases.
Not as rare as one would like. But not too bad unless you're doing heavy
filesytem work at the same time.
On Wednesday 21 January 2004 03.38, Glenn McCord
wrote:
> James Stone wrote:
> >>I run jack with:
> >>jackstart -R -v -d alsa -d hw:0
> >>
> >>...and I get xruns whenever I open a program, move windows around. Hell
> >>sometimes it does it when I'm just looking at it. More specifically, if
> >>I want to record in ardour, jack chokes up an xrun after about 2 seconds.
> >>
Is `jack' running with realtime priority, or is it merely SCHED_OTHER?
6:53 a.m.
New subject: [linux-audio-user] Which kernel for low latency and kernel 2.6.1-mm# problems
On Wednesday 21 January 2004 11.38, Steve Harris wrote:
On Wed, Jan 21, 2004 at 02:20:04AM -0800, Andrew
Morton wrote:
Its running SCHED_FIFO in this case.
- Steve
I'm not sure you're reading this list Andrew so I'll send directly also.
I just wanted to elaborate abit; -R in the argument line indicates that jack
should be running SCHED_FIFO, and since there are no specific settings for
period-size and number of periods, jack is probably defaulting to 2-periods
and 1024 samples period size. 2.4 works rather reliably with period-sizes
quite a bit smaller than that. I think 256 is commonly used, with good
hardware+drivers I suppose you could go even lower.
/Robert
need to
find these too.) Last I heard Andrew (cc:ed) thought it worked
as good as 2.4, except for some rare corner cases.
Not as rare as one would like. But not too bad unless you're doing heavy
filesytem work at the same time.
On Wednesday 21 January 2004 03.38, Glenn McCord
wrote:
> James Stone wrote:
> >>I run jack with:
> >>jackstart -R -v -d alsa -d hw:0
> >>
> >>...and I get xruns whenever I open a program, move windows around.
> >> Hell sometimes it does it when I'm just looking at it. More
> >> specifically, if I want to record in ardour, jack chokes up an
> >> xrun after about 2 seconds.
Is `jack' running with realtime priority, or is it merely SCHED_OTHER?
7:04 a.m.
New subject: [linux-audio-user] Which kernel for low latency and kernel 2.6.1-mm# problems
Robert Jonsson <robert.jonsson(a)dataductus.se> wrote:
On Wednesday 21 January 2004 11.38, Steve Harris wrote:
Thanks. I'm not scared of email ;)
On Wed, Jan 21, 2004 at 02:20:04AM -0800, Andrew
Morton wrote:
Its running SCHED_FIFO in this case.
- Steve
I'm not sure you're reading this list Andrew so I'll send directly also.
need to
find these too.) Last I heard Andrew (cc:ed) thought it worked
as good as 2.4, except for some rare corner cases.
Not as rare as one would like. But not too bad unless you're doing heavy
filesytem work at the same time.
On Wednesday 21 January 2004 03.38, Glenn McCord
wrote:
> James Stone wrote:
> >>I run jack with:
> >>jackstart -R -v -d alsa -d hw:0
> >>
> >>...and I get xruns whenever I open a program, move windows around.
> >> Hell sometimes it does it when I'm just looking at it. More
> >> specifically, if I want to record in ardour, jack chokes up an
> >> xrun after about 2 seconds.
Is `jack' running with realtime priority, or is it merely SCHED_OTHER? I just wanted to elaborate abit; -R in the argument
line indicates that jack
should be running SCHED_FIFO, and since there are no specific settings for
period-size and number of periods, jack is probably defaulting to 2-periods
and 1024 samples period size. 2.4 works rather reliably with period-sizes
quite a bit smaller than that. I think 256 is commonly used, with good
hardware+drivers I suppose you could go even lower.
I don't know what these numbers mean...
What does this transalate to in interval-in-milliseconds, and after how
many milliseconds delay will an underrun occur?
And what else is happening on the system at the time?
7:18 a.m.
New subject: [linux-audio-user] Which kernel for low latency and kernel 2.6.1-mm# problems
On Wed, Jan 21, 2004 at 03:01:19 -0800, Andrew Morton wrote:
The default sampe rate is 48kHz, so 1024 samples/block gives 21ms between
interupts. Jack easts a bit of that, but you'd have ~20ms before an
underrun occured.
I just wanted
to elaborate abit; -R in the argument line indicates that jack
should be running SCHED_FIFO, and since there are no specific settings for
period-size and number of periods, jack is probably defaulting to 2-periods
and 1024 samples period size. 2.4 works rather reliably with period-sizes
quite a bit smaller than that. I think 256 is commonly used, with good
hardware+drivers I suppose you could go even lower.
I don't know what these numbers mean...
What does this transalate to in interval-in-milliseconds, and after how
many milliseconds delay will an underrun occur? And what else is happening on the system at the time?
The original poster would have to anwer that. Jack itsself is just messing
with SYSV SHM and occasioanly touching fifos.
As someone else said, jack runs reliably on most 2.4+ll+o(1)sched systems
with 5ms (256 sample) interupt fequencies and usually lower.
- Steve
7:44 a.m.
New subject: [linux-audio-user] Which kernel for low latency and kernel 2.6.1-mm# problems
On Wed, 21 Jan 2004 11:15:11 +0000
Steve Harris <S.W.Harris(a)ecs.soton.ac.uk> wrote:
I usually use 4 or 8 pretty large periods of 512 frames [my soundcard
doesn't allow larger one]. On linux 2.4.22 [LL+preempt+cap patch] i can
get very stable performance. I can even compile a kernel in the
background and get no xruns [except for an occasional one]. I tested the
2.6.0 kernel and it was much more touchy. Start using the disk and xruns
occur right and left. I will try the 2.6.1 today though..
I don't know though if i configured the 2.6 kernel right [preemptible,
etc..]
I once took a look at the latency measuring tools, but i could not
really make sense out of them [not being a kernel hacker]. So i suppose
testing would be much easier, if there was a little tool, which everyone
could just run and it would do some testing which we could then report
back to andrew..
Flo
--
http://www.soundclick.com/bands/9/florianschmidt.htm
http://www.arted.biz/mista.tapas
I don't
know what these numbers mean...
What does this transalate to in interval-in-milliseconds, and after
how many milliseconds delay will an underrun occur?
The default sampe rate is 48kHz, so 1024 samples/block gives 21ms
between interupts. Jack easts a bit of that, but you'd have ~20ms
before an underrun occured.
And what else is happening on the system at the
time?
The original poster would have to anwer that. Jack itsself is just
messing with SYSV SHM and occasioanly touching fifos.
As someone else said, jack runs reliably on most 2.4+ll+o(1)sched
systems with 5ms (256 sample) interupt fequencies and usually lower.
7:56 a.m.
New subject: [linux-audio-user] Which kernel for low latency and kernel 2.6.1-mm# problems
And what else
is happening on the system at the time?
The original poster would have to anwer that. Jack itsself is just messing
with SYSV SHM and occasioanly touching fifos. 
7:41 a.m.
New subject: [linux-audio-user] Which kernel for low latency and kernel 2.6.1-mm# problems
At Wed, 21 Jan 2004 03:01:19 -0800,
Andrew Morton wrote:
a few months ago before 2.6.0 was released, i tested the audio latency
with different kernels. the result was shown in the internal
conference in SUSE, and i totally forgot to release the data until now
:)
maybe it will show you other aspects.
here you can find the slides
http://www.alsa-project.org/~iwai/audio-latency.pdf
some notes:
- the red line of the graph is the buffer size - when the plot
overcomes this line, the buffer underrun occurs, aka sound
dropout.
- performed on Athlon 2200+ / 256MB / SB live
- the kernel tested at that time was slightly old, 2.6.0-test10,
so the result with the latest kernel may differ.
- suse 2.4 kernel runs with HZ=1000 and O(1) scheduler
--
Takashi Iwai <tiwai(a)suse.de> ALSA Developer - www.alsa-project.org
I just wanted to elaborate abit; -R in the
argument line indicates that jack
should be running SCHED_FIFO, and since there are no specific settings for
period-size and number of periods, jack is probably defaulting to 2-periods
and 1024 samples period size. 2.4 works rather reliably with period-sizes
quite a bit smaller than that. I think 256 is commonly used, with good
hardware+drivers I suppose you could go even lower.
I don't know what these numbers mean...
What does this transalate to in interval-in-milliseconds, and after how
many milliseconds delay will an underrun occur?
And what else is happening on the system at the time?
5:10 p.m.
New subject: [linux-audio-user] Which kernel for low latency and kernel 2.6.1-mm# problems
Takashi Iwai <tiwai(a)suse.de> wrote:
a few months ago before 2.6.0 was released, i tested the audio latency
with different kernels. the result was shown in the internal
conference in SUSE, and i totally forgot to release the data until now
:)
maybe it will show you other aspects.
here you can find the slides
http://www.alsa-project.org/~iwai/audio-latency.pdf
OK. How is the suse 2.4 kernel patched in these tests? A form of the
low-latency patch?
I made some latency improvements to 2.6's ext3 recently, so it should be
performing significantly better than it was in 2.6.0-test9.
I'll do some more checks on 2.6 but as far as I know, it's performing OK.
If Jack is indeed running with realtime policy I'd be suspecting that
something other than the normal spends-too-long-in-the-kernel problem is
occurring.
Could someone give me a really simple description of how to obtain Jack,
and how to get it going sufficiently to demonstrate these problems?
Thanks.
6:11 p.m.
New subject: [linux-audio-user] Which kernel for low latency and kernel 2.6.1-mm# problems
Andrew Morton wrote:
Takashi Iwai <tiwai(a)suse.de> wrote:
Go to |/usr/src/linux/include/linux| (or wherever you have your kernel
sources) and in the file |capability.h| change the line
#define CAP_INIT_EFF_SET to_cap_t(~0&~CAP_TO_MASK(CAP_SETPCAP)
to
#define CAP_INIT_EFF_SET to_cap_t( ~0 )
and the line
#define CAP_INIT_INH_SET to_cap_t(0)
to
#define CAP_INIT_INH_SET to_cap_t( ~0 )
Also make sure CONFIG_TMPFS is turned on.
You must then recompile your kernel.
put this in /etc/fstab (you may have to ceate the folders)
shmfs /dev/shm shm defaults 0 0|
none /tmp/jack tmpfs defaults 0 0
||none /mnt/ramfs tmpfs defaults 0 0|
Get jack at http://jackit.sourceforge.net/
do a ./configure --with-default-tmpdir=/mnt/ramfs --enable-capabilities
make
make install
http://jackit.sourceforge.net/docs/faq.php is a good explanation of
everything anyway..
I start jack as a user with
$jackstart -R -v -d alsa -d hw:0
but if the compatability.h wasn't altered then you can start jack as
root with
#jackd -R -v -d alsa -d hw:0
There's an explanation of commnad line options at
http://www.djcj.org/LAU/jack/
I think that's everything.
I got xruns by opening programs but my audio tools are rezound and
ardour and they won't record much longer that 20 seconds before jack xruns.
I was the original poster. I found that if I used the 2.4.2 kernel with
the low-latency patch from
http://www.zip.com.au/~akpm/linux/schedlat.html#downloads and then
installed jack as above, I would get NO xruns using kde, ardour (has
multiple windows) and a network going. I've tried 2.6, 2.6.1 and patched
to -mm4 and mm5 but I get xruns within even fluxbox by doing the most
labour-unintensive computer tasks.
The -p option extends the buffer (is that the word?). Well, I didn't
need it with the 2.4.2 but in the 2.6 I made it -p 8192. It only
extended the xrun relief by a couple of seconds though. (ie it did jack all)
If you could throw any light on this then that would be absolutely great.
||
a few months ago before 2.6.0 was released, i
tested the audio latency
with different kernels. the result was shown in the internal
conference in SUSE, and i totally forgot to release the data until now
:)
maybe it will show you other aspects.
here you can find the slides
http://www.alsa-project.org/~iwai/audio-latency.pdf
OK. How is the suse 2.4 kernel patched in these tests? A form of the
low-latency patch?
I made some latency improvements to 2.6's ext3 recently, so it should be
performing significantly better than it was in 2.6.0-test9.
I'll do some more checks on 2.6 but as far as I know, it's performing OK.
If Jack is indeed running with realtime policy I'd be suspecting that
something other than the normal spends-too-long-in-the-kernel problem is
occurring.
Could someone give me a really simple description of how to obtain Jack,
and how to get it going sufficiently to demonstrate these problems?
Thanks.
6:47 p.m.
New subject: [linux-audio-user] Which kernel for low latency and kernel 2.6.1-mm# problems
Hi,
onsdagen den 21 januari 2004 23.05 skrev Glenn McCord:
Andrew Morton wrote:
I believe that the kernel change can be omitted if you run the app as root.
The --enable-capabilities can also be omitted in that case.
The tmpfs usage could call for some explanation:
jack uses the filesystem to store ipc pipes. It was discovered that accessing
these was the cause of xruns under kernel 2.4.
Thus it has been common to place these pipes on a tmpfs filesystem whereas the
xrun problem would not appear. I commonly have all of /tmp as tmpfs (then
jack doesn't need any special compilation flags).
I imagine this is a quite uncommon usage of tmpfs, maybe that's where the
problem lies with 2.6?
Could someone give me a really simple description
of how to obtain Jack,
and how to get it going sufficiently to demonstrate these problems?
Thanks.
Go to |/usr/src/linux/include/linux| (or wherever you have your kernel
sources) and in the file |capability.h| change the line
#define CAP_INIT_EFF_SET to_cap_t(~0&~CAP_TO_MASK(CAP_SETPCAP)
to
#define CAP_INIT_EFF_SET to_cap_t( ~0 )
and the line
#define CAP_INIT_INH_SET to_cap_t(0)
to
#define CAP_INIT_INH_SET to_cap_t( ~0 )
Also make sure CONFIG_TMPFS is turned on.
You must then recompile your kernel.
put this in /etc/fstab (you may have to ceate the folders)
shmfs /dev/shm shm defaults 0 0|
none /tmp/jack tmpfs defaults 0 0
||none /mnt/ramfs tmpfs defaults 0 0|
Get jack at http://jackit.sourceforge.net/
do a ./configure --with-default-tmpdir=/mnt/ramfs --enable-capabilities
make
make install
http://jackit.sourceforge.net/docs/faq.php is a good explanation of
everything anyway..
I start jack as a user with
$jackstart -R -v -d alsa -d hw:0
but if the compatability.h wasn't altered then you can start jack as
root with
#jackd -R -v -d alsa -d hw:0
Though not mandatory but jack gets a bit more stressed if we connect clients
to it. I'll try an explanation for how to get a simple setup going.
With jack there are a few simple clients. I propose connecting jack_metro.
with:
$ jack_metro -b 100
and then connect it to the jack soundcard output with:
$ jack_connect metro:100_bpm alsa_pcm:playback_1
this should result in a beeping sound at regular intervals. (extremely
annoying stuff)
In theory that should be enough to provoke the problems... Someone that has a
running kernel that actually is observing the problems, Glenn?, should try
this client-setup out and see if the problems occur with _it_ too.
There's an explanation of commnad line options at
http://www.djcj.org/LAU/jack/
I think that's everything.
I got xruns by opening programs but my audio tools are rezound and
ardour and they won't record much longer that 20 seconds before jack xruns.
I was the original poster. I found that if I used the 2.4.2 kernel with
the low-latency patch from
http://www.zip.com.au/~akpm/linux/schedlat.html#downloads and then
installed jack as above, I would get NO xruns using kde, ardour (has
multiple windows) and a network going. I've tried 2.6, 2.6.1 and patched
to -mm4 and mm5 but I get xruns within even fluxbox by doing the most
labour-unintensive computer tasks.
The -p option extends the buffer (is that the word?). Well, I didn't
need it with the 2.4.2 but in the 2.6 I made it -p 8192. It only
extended the xrun relief by a couple of seconds though. (ie it did jack
all)
8192 samples at 48khz is an horrendously long time, over 150 ms... there must
be something we've missed, clearly this should be possible to handle?
jack uses a rather clever ipc mechanism to contact all the clients with the
least amount of context switches, I remember there was some talk about 2.4
having trouble with it at times... (preventing us from going to 64
samples..kind of trouble)...
Could it be that some similar issue affects 2.6, but much worse ? But then
again, there are people running 2.6 with acceptable performance ???
Just throwing out ideas...
/Robert
If you could throw any light on this then that would be absolutely great.
6:52 p.m.
New subject: [linux-audio-user] Which kernel for low latency and kernel 2.6.1-mm# problems
Robert Jonsson <robert.jonsson(a)dataductus.se> wrote:
> Go to |/usr/src/linux/include/linux| (or wherever you have your kernel
> sources) and in the file |capability.h| change the line
Guys, I'm not subscribed to linux-audio-user! Could someone please
forward me the email from whcih the above words are taken?
Thanks.
6:54 p.m.
New subject: [linux-audio-user] Which kernel for low latency and kernel 2.6.1-mm# problems
Hi,
It's all in the message I sent, I didn't remove anything.
To be safe:
-----------------------------------------------
Andrew Morton wrote:
Takashi Iwai <tiwai(a)suse.de> wrote:
Go to |/usr/src/linux/include/linux| (or wherever you have your kernel
sources) and in the file |capability.h| change the line
#define CAP_INIT_EFF_SET to_cap_t(~0&~CAP_TO_MASK(CAP_SETPCAP)
to
#define CAP_INIT_EFF_SET to_cap_t( ~0 )
and the line
#define CAP_INIT_INH_SET to_cap_t(0)
to
#define CAP_INIT_INH_SET to_cap_t( ~0 )
Also make sure CONFIG_TMPFS is turned on.
You must then recompile your kernel.
put this in /etc/fstab (you may have to ceate the folders)
shmfs /dev/shm shm defaults 0 0|
none /tmp/jack tmpfs defaults 0 0
||none /mnt/ramfs tmpfs defaults 0 0|
Get jack at http://jackit.sourceforge.net/
do a ./configure --with-default-tmpdir=/mnt/ramfs --enable-capabilities
make
make install
http://jackit.sourceforge.net/docs/faq.php is a good explanation of
everything anyway..
I start jack as a user with
$jackstart -R -v -d alsa -d hw:0
but if the compatability.h wasn't altered then you can start jack as
root with
#jackd -R -v -d alsa -d hw:0
There's an explanation of commnad line options at
http://www.djcj.org/LAU/jack/
I think that's everything.
I got xruns by opening programs but my audio tools are rezound and
ardour and they won't record much longer that 20 seconds before jack xruns.
I was the original poster. I found that if I used the 2.4.2 kernel with
the low-latency patch from
http://www.zip.com.au/~akpm/linux/schedlat.html#downloads and then
installed jack as above, I would get NO xruns using kde, ardour (has
multiple windows) and a network going. I've tried 2.6, 2.6.1 and patched
to -mm4 and mm5 but I get xruns within even fluxbox by doing the most
labour-unintensive computer tasks.
The -p option extends the buffer (is that the word?). Well, I didn't
need it with the 2.4.2 but in the 2.6 I made it -p 8192. It only
extended the xrun relief by a couple of seconds though. (ie it did jack all)
If you could throw any light on this then that would be absolutely great.
||
a few months ago before 2.6.0 was released, i
tested the audio latency
with different kernels. the result was shown in the internal
conference in SUSE, and i totally forgot to release the data until now
:)
maybe it will show you other aspects.
here you can find the slides
http://www.alsa-project.org/~iwai/audio-latency.pdf
OK. How is the suse 2.4 kernel patched in these tests? A form of the
low-latency patch?
I made some latency improvements to 2.6's ext3 recently, so it should be
performing significantly better than it was in 2.6.0-test9.
I'll do some more checks on 2.6 but as far as I know, it's performing OK.
If Jack is indeed running with realtime policy I'd be suspecting that
something other than the normal spends-too-long-in-the-kernel problem is
occurring.
Could someone give me a really simple description of how to obtain Jack,
and how to get it going sufficiently to demonstrate these problems?
Thanks.
10:34 p.m.
New subject: [linux-audio-user] Which kernel for low latency and kernel 2.6.1-mm# problems
Robert Jonsson wrote:
Hi,
onsdagen den 21 januari 2004 23.05 skrev Glenn McCord:
With a jackstart -R -v -d alsa -d hw:0 -p 1024 I can get away with it If
I just look at it (I'm in fluxbox). But If open/close mozilla (ie. do
stuff) I get xruns.
Andrew Morton wrote:
I believe that the kernel change can be omitted if you run the app as root.
The --enable-capabilities can also be omitted in that case.
The tmpfs usage could call for some explanation:
jack uses the filesystem to store ipc pipes. It was discovered that accessing
these was the cause of xruns under kernel 2.4.
Thus it has been common to place these pipes on a tmpfs filesystem whereas the
xrun problem would not appear. I commonly have all of /tmp as tmpfs (then
jack doesn't need any special compilation flags).
I imagine this is a quite uncommon usage of tmpfs, maybe that's where the
problem lies with 2.6?
Could someone give me a really simple description
of how to obtain Jack,
and how to get it going sufficiently to demonstrate these problems?
Thanks.
Go to |/usr/src/linux/include/linux| (or wherever you have your kernel
sources) and in the file |capability.h| change the line
#define CAP_INIT_EFF_SET to_cap_t(~0&~CAP_TO_MASK(CAP_SETPCAP)
to
#define CAP_INIT_EFF_SET to_cap_t( ~0 )
and the line
#define CAP_INIT_INH_SET to_cap_t(0)
to
#define CAP_INIT_INH_SET to_cap_t( ~0 )
Also make sure CONFIG_TMPFS is turned on.
You must then recompile your kernel.
put this in /etc/fstab (you may have to ceate the folders)
shmfs /dev/shm shm defaults 0 0|
none /tmp/jack tmpfs defaults 0 0
||none /mnt/ramfs tmpfs defaults 0 0|
Get jack at http://jackit.sourceforge.net/
do a ./configure --with-default-tmpdir=/mnt/ramfs --enable-capabilities
make
make install
http://jackit.sourceforge.net/docs/faq.php is a
good explanation of
everything anyway..
I start jack as a user with
$jackstart -R -v -d alsa -d hw:0
but if the compatability.h wasn't altered then you can start jack as
root with
#jackd -R -v -d alsa -d hw:0
Though not mandatory but jack gets a bit more stressed if we connect clients
to it. I'll try an explanation for how to get a simple setup going.
With jack there are a few simple clients. I propose connecting jack_metro.
with:
$ jack_metro -b 100
and then connect it to the jack soundcard output with:
$ jack_connect metro:100_bpm alsa_pcm:playback_1
this should result in a beeping sound at regular intervals. (extremely
annoying stuff)
In theory that should be enough to provoke the problems... Someone that has a
running kernel that actually is observing the problems, Glenn?, should try
this client-setup out and see if the problems occur with _it_ too.
There's an explanation of commnad line options
at
http://www.djcj.org/LAU/jack/
I think that's everything.
I got xruns by opening programs but my audio tools are rezound and
ardour and they won't record much longer that 20 seconds before jack xruns.
I was the original poster. I found that if I used the 2.4.2 kernel with
the low-latency patch from
http://www.zip.com.au/~akpm/linux/schedlat.html#downloads and then
installed jack as above, I would get NO xruns using kde, ardour (has
multiple windows) and a network going. I've tried 2.6, 2.6.1 and patched
to -mm4 and mm5 but I get xruns within even fluxbox by doing the most
labour-unintensive computer tasks.
The -p option extends the buffer (is that the word?). Well, I didn't
need it with the 2.4.2 but in the 2.6 I made it -p 8192. It only
extended the xrun relief by a couple of seconds though. (ie it did jack
all)
8192 samples at 48khz is an horrendously long time, over 150 ms... there must
be something we've missed, clearly this should be possible to handle?
jack uses a rather clever ipc mechanism to contact all the clients with the
least amount of context switches, I remember there was some talk about 2.4
having trouble with it at times... (preventing us from going to 64
samples..kind of trouble)...
Could it be that some similar issue affects 2.6, but much worse ? But then
again, there are people running 2.6 with acceptable performance ???
Just throwing out ideas...
/Robert
If you could throw any light on this then that
would be absolutely great.
6:59 p.m.
New subject: [linux-audio-user] Which kernel for low latency and kernel 2.6.1-mm# problems
Andrew,
Thanks for all the work you've done in this area.
I am one of the JACK developers. I noticed many of the problems
discussed in this thread, but since I am still running 2.6.0, my
experience may not represent the best currently available version. I
will gladly build whatever version you recommend for comparison
purposes.
Overall, the unpatched 2.6 kernel has *much* better latency
characteristics than did 2.4. But, running the JACK applications that
I normally work with, it is still noticeably less responsive than 2.4
with your low-latency patch set (which runs very well indeed).
Andrew Morton <akpm(a)osdl.org> writes:
I'll do some more checks on 2.6 but as far as I
know, it's performing OK.
If Jack is indeed running with realtime policy I'd be suspecting that
something other than the normal spends-too-long-in-the-kernel problem is
occurring.
Could someone give me a really simple description of
how to obtain Jack,
and how to get it going sufficiently to demonstrate these problems?
You can download JACK via our web site...
http://jackit.sourceforge.net
It is not difficult to compile and install.
Quoting from the web site...
JACK is a low-latency audio server, written for POSIX conformant
operating systems such as GNU/Linux and Apple's OS X. It can connect
a number of different applications to an audio device, as well as
allowing them to share audio between themselves. Its clients can run
in their own processes (ie. as normal applications), or can they can
run within the JACK server (ie. as a "plugin").
JACK was designed from the ground up for professional audio work,
and its design focuses on two key areas: synchronous execution of
all clients, and low latency operation.
These two focus areas place strong demands on the OS scheduler.
During each audio period, the JACK server's SCHED_FIFO thread and one
for each client process must be dispatched without much delay.
Typical period sizes range from 64 frames (1.333 msec) to 2048 (42.667
msec). With a tuned system including a patched 2.4.19-ll kernel, I
can run a 32-frame period (0.667 msec), though not without occasional
xruns.
To run JACK SCHED_FIFO, start it with the -R parameter. For this to
work, you need access to realtime privileges. There are several
methods, all described in the web site. The simplest (and least
secure) is to run as `root'...
# jackd -Rv -d alsa -p256 -r48000
You need the ALSA sound driver for your audio device configured and
installed (not difficult with 2.6). For documentation, see...
http://www.alsa-project.org
The -p option sets the "period size" in frames, -r sets the sample
rate in frames per second. These parameters determine the basic audio
subsystem cycle time (period-size/sample-rate). Common sample rates
are 44100 frames/sec (for CD) and 48000 (for DAT).
The simplest JACK client to configure for playback is probably
alsaplayer (though there are many others).
http://www.alsaplayer.org
Unfortunately, if you run the JACK daemon as root you must also run
all its clients that way. This is one reason why we don't recommend
that method. But, it will serve to demonstrate the latency problem.
After jackd starts, type this in another window...
# alsaplayer -o jack somefile.wav
While the file is playing, try changing workspaces on the X display.
I find that with 2.6.0 and -p1024 (a 21.333 msec cycle) this works OK
until I switch to a workspace with a heavily loaded web browser (I
generally use galeon). On a lowlatency 2.4 kernel this is solid as a
rock, even with a much small period size.
If I can be of any assistence, don't hesitate to ask,
--
joq
7:12 p.m.
New subject: [linux-audio-user] Which kernel for low latency and kernel 2.6.1-mm# problems
Thanks everyone. It does start to look like a CPU scheduler problem.
Other possibilities are that
a) Jack is doing something unusual and is triggering some bug in 2.6
which causes the kernel to go into an extended sulk. Or
b) Some change in 2.6 is triggering a bug in Jack, causing Jack to go
into an extended sulk.
Question: have these problems been observed with other audio apps? With a
similar severity and frequency?
"Jack O'Quin" <joq(a)io.com> wrote:
hm, now here was me thinking the name meant "audio jack" ;)
...
Unfortunately, if you run the JACK daemon as root you must also run
all its clients that way.
Maybe Jack could switch UIDs and drop privileges after acquiring rt policy?
7:28 p.m.
New subject: [linux-audio-user] Which kernel for low latency and kernel 2.6.1-mm# problems
On Wed, Jan 21, 2004 at 03:10:22 -0800, Andrew Morton wrote:
It needs to keep them so that it can confer the SCHED_FIFO policy onto the
audio threads of client that connect to it.
- Steve
Question: have these problems been observed with other
audio apps? With a
similar severity and frequency?
Other audio apps? There are increasingly few of them :) JACK is a sound
server of sorts, and for many of us its the only thing that talks to the
hardware.
Unfortunately,
if you run the JACK daemon as root you must also run
all its clients that way.
Maybe Jack could switch UIDs and drop privileges after acquiring rt policy?
9:49 p.m.
New subject: [linux-audio-user] Which kernel for low latency and kernel 2.6.1-mm# problems
Andrew Morton <akpm(a)osdl.org> writes:
The server continues to need realtime privileges even after startup,
when new clients connect, for example. A lot of work has been done in
this area. With 2.4 the preferred solution was capabilities. With
2.6, we have been experimenting with an LSM for realtime privileges.
The new Security Module mechanism is a big step forward.
Here's a (very) preliminary version...
http://www.joq.us/realtime
--
joq
Thanks everyone. It does start to look like a CPU
scheduler problem.
Other possibilities are that
a) Jack is doing something unusual and is triggering some bug in 2.6
which causes the kernel to go into an extended sulk. Or
b) Some change in 2.6 is triggering a bug in Jack, causing Jack to go
into an extended sulk.
JACK is a heavy user of pthreads. NPTL is another difference between
2.4 and 2.6. I have not heard any reports of problems with the
interaction of NPTL and JACK, but this certainly remains a
possibility.
How can we zero in on what's really happening?
Question: have these problems been observed with other
audio apps? With a
similar severity and frequency?
I don't run non-JACK audio applications much. My impression is that
there are fewer problems. They typically don't require so many thread
dispatches per buffer, and they often use much bigger buffers because
low latency is not always important.
"Jack O'Quin" <joq(a)io.com> wrote:
hm, now here was me thinking the name meant "audio jack" ;)
It does. The acronym is "JACK Audio Connection Kit".
Paul Davis is the primary author. The name was selected before I
started working on it. :-)
Unfortunately,
if you run the JACK daemon as root you must also run
all its clients that way.
Maybe Jack could switch UIDs and drop privileges after acquiring rt policy?
22 Jan
22 Jan
7:28 a.m.
New subject: [linux-audio-user] Which kernel for low latency and kernel 2.6.1-mm# problems
On 21 Jan 2004 19:46:13 -0600
"Jack O'Quin" <joq(a)io.com> wrote:
Here's a (very) preliminary version...
http://www.joq.us/realtime
Is there a link to this in the JACK docs? i couldn't find it. A good
place would be the Jack FAQ i think. 'Cause this is gonna be a FAQ for
sure..
Flo
P.S.: Maybe i'm just blindstruck though..
--
http://www.soundclick.com/bands/9/florianschmidt.htm
http://www.arted.biz/mista.tapas
6:05 a.m.
New subject: [linux-audio-user] Which kernel for low latency and kernel 2.6.1-mm# problems
At Wed, 21 Jan 2004 13:08:36 -0800,
Andrew Morton wrote:
Takashi Iwai <tiwai(a)suse.de> wrote:
yes, it's a la LL by Andrea.
a few months ago before 2.6.0 was released, i tested the audio latency
with different kernels. the result was shown in the internal
conference in SUSE, and i totally forgot to release the data until now
:)
maybe it will show you other aspects.
here you can find the slides
http://www.alsa-project.org/~iwai/audio-latency.pdf
OK. How is the suse 2.4 kernel patched in these tests? A form of the
low-latency patch? I made some latency improvements to 2.6's ext3
recently, so it should be
performing significantly better than it was in 2.6.0-test9.
oh it's good to hear!
i've been busy for other things but i'd like to test the latest kernel
again if i find time. i'll inform you, too, of course :)
Takashi
21 Jan
21 Jan
7:26 p.m.
New subject: [linux-audio-user] Which kernel for low latency and kernel 2.6.1-mm# problems
Takashi, it would be really, really useful if we could modify the ALSA
drivers to identify at interrupt time when an underrun has occurred and to
drop a stack dump at that point. Would that be possible? Something like:
foo_interrupt()
{
...
if (there is no audio left to play) {
if (sysctl_debug_audio_underruns) {
printk("audio underrun!\n");
dump_stack();
}
}
...
}
The backtrace will tell us what the kernel was doing when it should have
been context switching instead. People can set the sysctl and send angry
emails to kernel developers.
Is this possible?
22 Jan
22 Jan
6:19 a.m.
New subject: [linux-audio-user] Which kernel for low latency and kernel 2.6.1-mm# problems
At Wed, 21 Jan 2004 15:24:22 -0800,
Andrew Morton wrote:
Takashi, it would be really, really useful if we could modify the ALSA
drivers to identify at interrupt time when an underrun has occurred and to
drop a stack dump at that point. Would that be possible? Something like:
foo_interrupt()
{
...
if (there is no audio left to play) {
if (sysctl_debug_audio_underruns) {
printk("audio underrun!\n");
dump_stack();
}
}
...
}
The backtrace will tell us what the kernel was doing when it should have
been context switching instead. People can set the sysctl and send angry
emails to kernel developers.
Is this possible?
sure, we have already the underrun/overrun detection in the ALSA
common PCM layer (sound/core/pcm_lib.c: snd_pcm_update_hw_ptr_post).
just adding the code like above should work.
Takashi
7368
days inactive
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linux-audio-user@lists.linuxaudio.org
63 comments
16 participants
participants (16)
-
Alex Timmer -
Andrew Gaydenko -
Andrew Morton -
Eric Dantan Rzewnicki -
Florian Schmidt -
Frank Barknecht -
Gian Paolo Mureddu -
Glenn McCord -
Jack O'Quin -
James Stone -
lee＠fallingforward.net -
martijn -
Robert Jonsson -
Steve Harris -
Takashi Iwai -
Tommi Sakari Uimonen