Re: [LAU] kontakt 5 - finally, I am hearing something...

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To: Csillag Kristof <csillag.kristof@...>
Cc: <linux-audio-user@...>
Date: Monday, December 19, 2011 - 5:33 pm

On 12/19/2011 05:11 PM, Csillag Kristof wrote:

Indeed. Congrats.

Are you using the free-of-charge Kontakt player or the full K5 version?

> I can see the following differences:

There'll be performance differences when it comes to low latency.
running it under wine will require an extra context-switch. I don't know
if WineASIO works around this, but I think it does not.

Not too long ago there was an email on LAD by Paul Davis who explained
ardour's native VST/wine strategy. IIRC the whole app was run in the
context of wine to forego the extra context-switch; but I don't know the
details. He may chime in.

http://old.nabble.com/Kontakt-Spikes-td32614159.html
May actually have some insight as well..

> - Only approach 3 gives me direct JACK midi input. (But I guess I can

Where there's a will, there's a way :)

>

It'd be great if you could document this setup or write a blog-post when
you're done.

Well, most of it is already there scattered over the last couple of
emails so it should not be much work.

> * * *

2 months out of business and I lost track of those :)

> - how should I choose my kernel version ,

For a professional studio setup you'll want a realtime-kernel for
reliability (it must be the time of the year again, I wrote this two
times today already).

http://www.kernel.org/pub/linux/kernel/projects/rt/

I have good stable experience with 3.0.6-rt17 on 64bit; there were some
b0rked versions after that and I have not yet tried 3.0.12-rt30 nor
3.2-rc5-rt8.

> - what to compile into my kernel,

Maybe you can get away with some stock kernel, from Arch or AVLinux;
otherwise:

CONFIG_TREE_PREEMPT_RCU=y
CONFIG_PREEMPT_RCU=y
CONFIG_PREEMPT=y
CONFIG_PREEMPT_RT_FULL=y
CONFIG_IRQ_FORCED_THREADING=y
CONFIG_NO_HZ=y
CONFIG_HIGH_RES_TIMERS=y
CONFIG_HZ_1000=y
CONFIG_HZ=1000
CONFIG_HPET_TIMER=y

disable CONFIG_RT_GROUP_SCHED
or walk through http://trac.jackaudio.org/wiki/Cgroups

Avoid *_TRACE and *DEBUG* and *_ACCOUNTING options in general; although
many of those e.g. CONFIG_LATENCYTOP=y or CONFIG_PM_DEBUG=y don't have
negative impact unless you explictly enable them during runtime; this is
usually documented in the help for the option.

http://old.nabble.com/IO-scheduler-for-realtime-audio--td30624684.html
might be helpful as well.

> - how to configure my kernel run-time,

boot option 'threadirqs'; and Rui's rtirq: http://alsa.opensrc.org/Rtirq
debian already takes are of /etc/security/limits.d/audio.conf

CPU frequency scaling works fine on most systems these days - even on
low latency systems. But PCI-bus or FSB freq. scaling is still often an
issue. Chipsets vary a lot WRT to that. In doubt: disable it in the BIOS
(look for sth like 'C1E halt state' and/or 'EIST' and disable them).

> - how to patch / configure wine,

Should work fine OOTB.

> - etc

"best" is somewhat ambiguous in that context. I assumed you meant a
reliable low-latency system.

> (I know this gets talked about all the time, but everything is changing

indeed.

> I am not asking you to repeat what is is already stated, but to point me

too late :)
Cheers!
robin

> Thank you for your help:

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Messages in current thread:
[LAU] kontakt 5 - finally, I am hearing something..., Csillag Kristof, (Mon Dec 19, 4:11 pm)
Re: [LAU] kontakt 5 - finally, I am hearing something..., Nicola Pandini, (Mon Dec 19, 8:33 pm)
Re: [LAU] kontakt 5 - finally, I am hearing something..., Robin Gareus, (Mon Dec 19, 5:33 pm)
Re: [LAU] kontakt 5 - finally, I am hearing something..., Csillag Kristof, (Wed Dec 21, 4:04 pm)
Re: [LAU] kontakt 5 - finally, I am hearing something..., Jeremy Jongepier, (Tue Dec 20, 8:07 am)