Low-Latency Kernel

[Chuckk Hubbard]

Hello.
I'm using this how-to:

http://demudi.agnula.org/wiki/Low-latencyKernelBuildingHowto

On my laptop. Can anyone tell me if this is the latest how-to?
Everything works fine except this libpam module business; the deb file
linked to is no longer there, and I can't find it anywhere online. Is
this still the way to go, or have things changed in the last couple of
months?

Thanks!
-Chuckk

[tim hall]

Post by Chuckk Hubbard
http://demudi.agnula.org/wiki/Low-latencyKernelBuildingHowto
On my laptop.  Can anyone tell me if this is the latest how-to?
Everything works fine except this libpam module business; the deb file
linked to is no longer there, and I can't find it anywhere online.  Is
this still the way to go, or have things changed in the last couple of
months?

Try here:

http://ftp.techweb.rfa.org/debrfa/dists/etch/main/binary-i386/

[Chuckk Hubbard]

Post by tim hall

Post by Chuckk Hubbard
http://demudi.agnula.org/wiki/Low-latencyKernelBuildingHowto
On my laptop. Can anyone tell me if this is the latest how-to?
Everything works fine except this libpam module business; the deb file
linked to is no longer there, and I can't find it anywhere online. Is
this still the way to go, or have things changed in the last couple of
months?

http://ftp.techweb.rfa.org/debrfa/dists/etch/main/binary-i386/

That looks a lot like the version the article I referenced says not to
use. Do you know if this libpam is "rlimits aware"?

Thanks.
-Chuckk

[tim hall]

Post by Chuckk Hubbard

Post by tim hall

Post by Chuckk Hubbard
http://demudi.agnula.org/wiki/Low-latencyKernelBuildingHowto
On my laptop. Can anyone tell me if this is the latest how-to?
Everything works fine except this libpam module business; the deb file
linked to is no longer there, and I can't find it anywhere online. Is
this still the way to go, or have things changed in the last couple of
months?

http://ftp.techweb.rfa.org/debrfa/dists/etch/main/binary-i386/

That looks a lot like the version the article I referenced says not to
use. Do you know if this libpam is "rlimits aware"?

Yes, it's a patched version.

[Chuckk Hubbard]

Sweet, thanks.
Alas, apparently the guide I'm using is out of date:
http://www.linuxdevices.com/news/NS9566944929.html

So the millions of xruns I'm getting apparently won't be fixed by Ingo
Molnar's rt patch because it no longer exists. I was afraid of this.
I'll have to learn more than I wanted to learn. But it's good to
know.
-Chuckk

Post by tim hall
Yes, it's a patched version.
--
cheers,
tim hall
http://glastonburymusic.org.uk/tim
We are the people We've been waiting for.
_______________________________________________
Users mailing list
http://lists.agnula.org/cgi-bin/mailman/listinfo/users

[tim hall]

Post by Chuckk Hubbard
So the millions of xruns I'm getting apparently won't be fixed by Ingo
Molnar's rt patch because it no longer exists.  I was afraid of this.
I'll have to learn more than I wanted to learn.  But it's good to
know.

Ingo Molnar's patches tend to reduce latency to fussily small amounts. His
work is slowly being incorporated into the mainline kernel AFAIU. The most
likely cause of Xruns is that you haven't set up your system to allow
realtime scheduling as root, this is what using the patched PAM modules is
all about. I'm using an unpatched 2.6.16 kernel at the moment plus the
patched (rtlimits aware) PAM packages from here:
http://ftp.techweb.rfa.org/debrfa/dists/etch/main/binary-i386/
There are other ways of allowing ordinary users to make use of realtime
scheduling (realtime-lsm and set-rtlimits) but I don't recommend them.

I found it easier than configuring CUPS, YMMV.

[Chuckk Hubbard]

Hello again. Can you tell me, possibly, what packages from your link
I'll need? I only have libpam-modules so far, since it was the only
one I saw mentioned on that page, but I still get insane xruns. I
hate to admit it, but I'm also still totally clueless about
configuring my system and programs for real-time.
Thank you!
-Chuckk

Post by tim hall

Post by Chuckk Hubbard
So the millions of xruns I'm getting apparently won't be fixed by Ingo
Molnar's rt patch because it no longer exists. I was afraid of this.
I'll have to learn more than I wanted to learn. But it's good to
know.

Ingo Molnar's patches tend to reduce latency to fussily small amounts. His
work is slowly being incorporated into the mainline kernel AFAIU. The most
likely cause of Xruns is that you haven't set up your system to allow
realtime scheduling as root, this is what using the patched PAM modules is
all about. I'm using an unpatched 2.6.16 kernel at the moment plus the
http://ftp.techweb.rfa.org/debrfa/dists/etch/main/binary-i386/
There are other ways of allowing ordinary users to make use of realtime
scheduling (realtime-lsm and set-rtlimits) but I don't recommend them.
I found it easier than configuring CUPS, YMMV.
--
cheers,
tim hall
http://glastonburymusic.org.uk/tim
We are the people We've been waiting for.
_______________________________________________
Users mailing list
http://lists.agnula.org/cgi-bin/mailman/listinfo/users

[Chuckk Hubbard]

Thanks for your advice on this, Tim. I installed all of the libpam
packages from your link and restarted, and it seems to have made a
difference.
Fluidsynth is still fussy though.
fluidsynth: warning: ALSA sequencer buffer overrun, lost events

Any idea what I might do to stop that?
-Chuckk

Post by tim hall

Post by Chuckk Hubbard
So the millions of xruns I'm getting apparently won't be fixed by Ingo
Molnar's rt patch because it no longer exists. I was afraid of this.
I'll have to learn more than I wanted to learn. But it's good to
know.

Ingo Molnar's patches tend to reduce latency to fussily small amounts. His
work is slowly being incorporated into the mainline kernel AFAIU. The most
likely cause of Xruns is that you haven't set up your system to allow
realtime scheduling as root, this is what using the patched PAM modules is
all about. I'm using an unpatched 2.6.16 kernel at the moment plus the
http://ftp.techweb.rfa.org/debrfa/dists/etch/main/binary-i386/
There are other ways of allowing ordinary users to make use of realtime
scheduling (realtime-lsm and set-rtlimits) but I don't recommend them.
I found it easier than configuring CUPS, YMMV.
--
cheers,
tim hall
http://glastonburymusic.org.uk/tim
We are the people We've been waiting for.
_______________________________________________
Users mailing list
http://lists.agnula.org/cgi-bin/mailman/listinfo/users

[tim hall]

Post by Chuckk Hubbard
Thanks for your advice on this, Tim. I installed all of the libpam
packages from your link and restarted, and it seems to have made a
difference.

Have you set appropriate limits in /etc/security/limits.conf?

Post by Chuckk Hubbard
Fluidsynth is still fussy though.
fluidsynth: warning: ALSA sequencer buffer overrun, lost events
Any idea what I might do to stop that?

Not without further information, sorry.

[Chuckk Hubbard]

Post by tim hall

Post by Chuckk Hubbard
Thanks for your advice on this, Tim. I installed all of the libpam
packages from your link and restarted, and it seems to have made a
difference.

Have you set appropriate limits in /etc/security/limits.conf?

I will try that if I can salvage this install, thanks.

Post by tim hall

Post by Chuckk Hubbard
Fluidsynth is still fussy though.
fluidsynth: warning: ALSA sequencer buffer overrun, lost events
Any idea what I might do to stop that?

Not without further information, sorry.

Not sure what information to give... the documentation I can find for
fluidsynth is scanty, not sure how to use it.
I did get it to function passably using the -z and -c options, but I
won't be able to give more info unless I can fix the system, it
spontaneously stopped booting last night with Grub error 24... and the
info I can find on that is scanty as well. Next time I'll know to
burn an extra Linux install CD before leaving home!
Thanks for your help though.

[Chuckk Hubbard]

Hi again Tim. I replaced the laptop on which I was having the xruns
with a new one, and am going through getting my installation set up.
Do you happen to know of any libpam deb files for amd64?
Thanks.
-Chuckk

Post by tim hall

Post by Chuckk Hubbard
So the millions of xruns I'm getting apparently won't be fixed by Ingo
Molnar's rt patch because it no longer exists. I was afraid of this.
I'll have to learn more than I wanted to learn. But it's good to
know.

Ingo Molnar's patches tend to reduce latency to fussily small amounts. His
work is slowly being incorporated into the mainline kernel AFAIU. The most
likely cause of Xruns is that you haven't set up your system to allow
realtime scheduling as root, this is what using the patched PAM modules is
all about. I'm using an unpatched 2.6.16 kernel at the moment plus the
http://ftp.techweb.rfa.org/debrfa/dists/etch/main/binary-i386/
There are other ways of allowing ordinary users to make use of realtime
scheduling (realtime-lsm and set-rtlimits) but I don't recommend them.
I found it easier than configuring CUPS, YMMV.
--
cheers,
tim hall
http://glastonburymusic.org.uk/tim
We are the people We've been waiting for.
_______________________________________________
Users mailing list
http://lists.agnula.org/cgi-bin/mailman/listinfo/users

[tim hall]

Hi again Tim.  I replaced the laptop on which I was having the xruns
with a new one, and am going through getting my installation set up.
Do you happen to know of any libpam deb files for amd64?

No, I think 64studio is still using realtime-lsm.

[moebius]

Bonsoir,
Anyway, in ubuntu edgy (6.10), libpam is patched (it's noticed in the
changelog and there's a /etc/security/limitsconf) since spring 2006 it
seems...

see
http://www.linuxmao.org/tikiwiki/tiki-index.php?page=Acc%C3%A8s%20temps%20r%C3%A9el%20pour%20les%20applications&comzone=show#comments

in french I'm afraid...
So I think you can get pam from ubuntu edgy repositories
cordialement,

Post by tim hall

Post by Chuckk Hubbard
Hi again Tim. I replaced the laptop on which I was having the xruns
with a new one, and am going through getting my installation set up.
Do you happen to know of any libpam deb files for amd64?

No, I think 64studio is still using realtime-lsm.