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Old 06-16-2005, 05:57 PM   #1
friendly_guy
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enabling low latency 2.6 kernel


Hi

I want to recompile my kernel for music making. I gather that the low latency patch that was applied to linux 2.4 is built into 2.6.

When I use 'make xconfig' I cannot find the tab to enable/disable it. I have tried google & the site search. Can anyone tell me where it is while my blood pressure is still at a non lethal level?

Thanks

Guy
 
Old 06-16-2005, 06:06 PM   #2
Electro
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Look for preemptive. Sorry, I do not remember where it is at.
 
Old 06-16-2005, 06:12 PM   #3
egag
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with xconfig. look under " processor type and features "
it's " preemptible kernel " your looking for i guess.

also i think you need the " realtime " module, that can give users realtime capabilities. ( maybe you already have it, but anyway...)

http://sourceforge.net/projects/realtime-lsm/

read the readme etc.
it requires also to select under " security " the option "capability " to be a module.
more info in the readme + doc.

btw...if you use it, either the realtime or the capability module can be loaded.
(for ex.: i can run bind or make music, not both cuz bind/named needs the cap. module )

egag
 
Old 06-16-2005, 06:23 PM   #4
friendly_guy
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I had understood that the preemptive capabilities & the low latency were two different things eg:

http://www.linuxdevices.com/articles/AT8906594941.html

I had already found & enabled preemptible Kernel but was looking for low latency as well.

Thanks for your interest

Guy
 
Old 06-17-2005, 01:19 AM   #5
Electro
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The link that egag gave is very old. There is now 0.8.5 for realtime-lsm at http://www.joq.us/.

I can record audio with 96 KHz at 24-bit resolution for two channels with no problems using audacity and just the preemptive setting in the kernel. My sound card is an Audiotrak Prodigy 7.1 and I used an XFS partition for the recordings.
 
Old 06-17-2005, 01:42 AM   #6
foo_bar_foo
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i don't think there is a latency patch for 2.6 ? not that i know of anyway
preemption is certainly the key to low latency
the 2.6 kernels softIRQ handlers seem to work fine for me without patching

i guess just try it that way straight out of the box and see
there are lots of little gotchas but if you are lucky it will work fine (mine did)

if yours won't run ok there is this
http://www.affenbande.org/~tapas/wik...y%20Preemption

read
http://www.affenbande.org/~tapas/wik...0linux%202.6.x
 
Old 06-17-2005, 08:01 AM   #7
egag
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Quote:
Originally posted by Electro
The link that egag gave is very old. There is now 0.8.5 for realtime-lsm at http://www.joq.us/.
oh...i thought sourceforge.net was up to date ( but it isn't ... ).
thanks for the link.

egag
 
  


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