[LAU] ALSA and RME Raydat troubleshooting

[Ralf Mardorf]

On Tue, 2014-10-21 at 17:52 +0200, Guido Aulisi wrote:
> Threadirq works with vanilla kernels.
> In the kernel docs:
> 
> threadirqs      [KNL]
>  Force threading of all interrupt handlers except those
>  marked explicitly IRQF_NO_THREAD.

But does it cause a noticeable improvement? Since you're using it the
answer likely is, that it does ;). I'll test it :).

> It's not an RT kernel

Yes, but there are different increments of preemption available,
depending on the settings when you compile a vanilla kernel ...or I'm
mistaken? Are those settings only available for rt patched kernels?

[rocketmouse at archlinux ~]$ uname -r
3.16.4-1-ARCH
[rocketmouse at archlinux ~]$ zgrep PREE /proc/config.gz
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
CONFIG_PREEMPT_COUNT=y
# CONFIG_DEBUG_PREEMPT is not set
# CONFIG_PREEMPT_TRACER is not set
[rocketmouse at archlinux ~]$ grep PREE /usr/src/linux-3.10.47-rt50-1-rt-lts/.config
CONFIG_TREE_PREEMPT_RCU=y
CONFIG_PREEMPT_RCU=y
CONFIG_PREEMPT_NOTIFIERS=y
CONFIG_PREEMPT=y
CONFIG_PREEMPT_RT_BASE=y
CONFIG_HAVE_PREEMPT_LAZY=y
CONFIG_PREEMPT_LAZY=y
# CONFIG_PREEMPT_NONE is not set
# CONFIG_PREEMPT_VOLUNTARY is not set
# CONFIG_PREEMPT__LL is not set
# CONFIG_PREEMPT_RTB is not set
CONFIG_PREEMPT_RT_FULL=y
CONFIG_PREEMPT_COUNT=y
# CONFIG_DEBUG_PREEMPT is not set
# CONFIG_PREEMPT_TRACER is not set

Ok, full preempt seems to need the rt patch.
Hm?
http://stackoverflow.com/questions/21997122/linux-kernel-preemption-levels