[LAU] Kernel 2.6.39

James Warden warjamy at yahoo.com
Thu Jun 23 07:59:29 UTC 2011



--- On Thu, 6/23/11, Rui Nuno Capela <rncbc at rncbc.org> wrote:

> From: Rui Nuno Capela <rncbc at rncbc.org>
> Subject: Re: [LAU] Kernel 2.6.39
> To: linux-audio-user at lists.linuxaudio.org
> Date: Thursday, June 23, 2011, 3:42 AM
> On 06/23/2011 07:17 AM, Ralf Mardorf
> wrote:
> >
> > I used the config from the self-build kernel
> 2.6.33.9-rt31 and run
> > oldconfig only to configure 2.6.39. I didn't make
> music until now using
> > this kernel. Yes, I wish to "emulate" the PREEMPT_RT,
> since common
> > PREEMPT only kernels never did, what I needed.
> >
> > What do I need to set?
> >
> > $ cat config-2.6.39.1 | grep PREEMPT
> > CONFIG_TREE_PREEMPT_RCU=y
> > CONFIG_PREEMPT_RCU=y
> > CONFIG_PREEMPT_NOTIFIERS=y
> > # CONFIG_PREEMPT_NONE is not set
> > # CONFIG_PREEMPT_VOLUNTARY is not set
> > CONFIG_PREEMPT=y
> >
> > IIUC this is correct?!
> >
> 
> yes.
> 
> and don't forget to add "threadirqs" to your kernel
> bootloader 
> line--only then you'll get "rtirq" to do its magic as it
> used to do on a 
> genuine -rt kernel.
> 

And remember to use /etc/default/grub to have this threadirqs boot option permanent:

/etc/default/grub : GRUB_CMDLINE_LINUX="threadirqs"

if you are too lazy to compile / recompile /etc, just use the liquorix debian kernel (http://liquorix.net/)

I use that one (kernel compiled with CONFIG_PREEMPT=y, threadirqs at boot). It does wonders! I tried the cyclictest mentioned by Rui and I got some quite outstanding numbers on my system.


(However, the liquorix kernel is not PAE, which prevents the use of more than 4GB RAM for 32bit systems with more than 4GB of physical RAM)

J.


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