11 Mar
2004
11 Mar
'04
4:39 a.m.
Yes. I have pre-empt enabled from the kernel configuration. Is there
something I need to do from the running system to enable it?
(I mean something like:
echo 1 > /proc/sys/.../lowlatency )
Sampo
Frank Barknecht <fbar(a)footils.org>rg>:
Hallo,
Sampo Savolainen hat gesagt: // Sampo Savolainen wrote:
----- Edelleenlähetetty viesti päättyy -----
I'm trying to get jack & ardour working
with the 2.6.x kernels. Do you
have any hints/tips? I've now tried:
debian 2.6.2
debian 2.6.3
debian 2.6.3 modified with LSM support + realtime module
standard 2.6.4-rc2-mm1 (couldn't get realtime module working)
standard 2.6.3-mm4 LSM support + realtime module (kinda working..)
None of these have provided me with sufficient latency. Jack keeps
throwing Ardour out for stupid reasons like closing the mixer window.
(with realtime module, I mean http://www.joq.us/realtime/)
Is there some magic trick I've forgotten to do, or I haven't heard of?
I
have DMA enabled on my harddrive, and this same
system runs like dream
with 2.4 kernels.
Just to make sure: you did enable kernel preemption, didn't you?
ciao
--
Frank Barknecht _ ______footils.org__
11 Mar
11 Mar
1:26 p.m.
New subject: [linux-audio-user] Kernel 2.6.x latency
Hallo,
Sampo Savolainen hat gesagt: // Sampo Savolainen wrote:
Yes. I have pre-empt enabled from the kernel
configuration. Is there
something I need to do from the running system to enable it?
(I mean something like:
echo 1 > /proc/sys/.../lowlatency )
No, you don't need something like this for preempt, AFAIK.
Another thing to check would be your X server's nice value. This used
to be "-10" in older Debians, but should not be set at all with 2.6.
Check this in /etc/X11/Xwrapper.config or
/etc/X11/Xwrapper.config.xserver-common-debconf
ciao
--
Frank Barknecht _ ______footils.org__
3:58 p.m.
New subject: [linux-audio-user] Kernel 2.6.x latency
On Thu, Mar 11, 2004 at 06:21:15PM +0100, Frank Barknecht wrote:
Hallo,
Sampo Savolainen hat gesagt: // Sampo Savolainen wrote:
How disappointing.. I just tried this, and it didn't help.. I was almost
sure this was going to work. I am still getting many more xruns than
with the low latency 2.4.x kernels though at least I am not getting
xruns on opening and closing windows!
However, on doing a top in 2.6.x I noticed that quite a few processes
are running with a nice of -10 (something called "event" among
others..). This does not appear to be the case in 2.4.x.. perhaps this
could be the source of the trouble.. not really sure how to fix it
though.
I will have to stick with 2.4.25 for the time being by the looks of
things.
James
Yes. I have pre-empt enabled from the kernel
configuration. Is there
something I need to do from the running system to enable it?
(I mean something like:
echo 1 > /proc/sys/.../lowlatency )
No, you don't need something like this for preempt, AFAIK.
Another thing to check would be your X server's nice value. This used
to be "-10" in older Debians, but should not be set at all with 2.6.
Check this in /etc/X11/Xwrapper.config or
/etc/X11/Xwrapper.config.xserver-common-debconf
ciao
--
Frank Barknecht _ ______footils.org__ 
4:57 p.m.
New subject: [linux-audio-user] Kernel 2.6.x latency
James Stone <stone1(a)btinternet.com> writes:
On Thu, Mar 11, 2004 at 06:21:15PM +0100, Frank
Barknecht wrote:
> Another thing to check would be your X
server's nice value. This used
> to be "-10" in older Debians, but should not be set at all with 2.6.
How disappointing.. I just tried this, and it
didn't help.. I was almost
sure this was going to work. I am still getting many more xruns than
with the low latency 2.4.x kernels though at least I am not getting
xruns on opening and closing windows!
However, on doing a top in 2.6.x I noticed that quite a few processes
are running with a nice of -10 (something called "event" among
others..). This does not appear to be the case in 2.4.x.. perhaps this
could be the source of the trouble.. not really sure how to fix it
though.
This makes me wonder if there is a bug in the scheduler. IIUC, a
realtime thread is *supposed* to have higher priority than any
non-SCHED_FIFO thread, regardless of "nice" value.
If we can nail down a case where this is definitely happening, someone
should report it to Andrew Morton.
I will have to stick with 2.4.25 for the time being by
the looks of
things.
You can almost certainly get better low-latency results that way, at
least for the moment. I hope that over time 2.6.x will become just as
good.
--
joq
7:12 p.m.
New subject: [linux-audio-user] Kernel 2.6.x latency
On Thu, Mar 11, 2004 at 02:52:08PM -0600, Jack O'Quin wrote:
James Stone <stone1(a)btinternet.com> writes:
I have just done some further testing: using my SBLive, running muse and
zynaddsubfx through jack (started with qjackctl), if I set the nice
value of XFree86 to 0, I do not get xruns when switching workspaces or
opening a new terminal, but with a nice value of -20 I get several xruns
in both situations.. I can also get xruns running jackd as root and
opening several aterms while it is connected to hydrogen.
although with nice 0 it is close to usable, I still get xruns on
starting new programs connecting to jackd, whereas with 2.4.25/low
latency this does not occur.
James.
On Thu, Mar 11, 2004 at 06:21:15PM +0100, Frank
Barknecht wrote:
> Another thing to check would be your X
server's nice value. This used
> to be "-10" in older Debians, but should not be set at all with 2.6.
How disappointing.. I just tried this, and it
didn't help.. I was almost
sure this was going to work. I am still getting many more xruns than
with the low latency 2.4.x kernels though at least I am not getting
xruns on opening and closing windows!
However, on doing a top in 2.6.x I noticed that quite a few processes
are running with a nice of -10 (something called "event" among
others..). This does not appear to be the case in 2.4.x.. perhaps this
could be the source of the trouble.. not really sure how to fix it
though.
This makes me wonder if there is a bug in the scheduler. IIUC, a
realtime thread is *supposed* to have higher priority than any
non-SCHED_FIFO thread, regardless of "nice" value.
If we can nail down a case where this is definitely happening, someone
should report it to Andrew Morton.
7566
days inactive
7566
days old
linux-audio-user@lists.linuxaudio.org
4 comments
4 participants
participants (4)
-
Frank Barknecht -
Jack O'Quin -
James Stone -
Sampo Savolainen