Re: [LAU] Too many xruns

On 10/11/2012 06:17 PM, Kevin Cosgrove wrote:
>
> On 11 October 2012 at 6:55, Paul Davis <paul@email-addr-hidden> wrote:
>
>> 2. chrt: failed to set pid 0's policy: Operation not permitted
>>> Checking the ability to prioritize processes with chrt... no - not good
>>> Could not assign a 80 rtprio value. Set up limits.conf.
>>> For more information, see
>>>
>>> http://wiki.linuxmusicians.com/doku.php?id=system_configuration#limits.conf
>>>
>>> I did make the changes outlined at the above link. I still
>>> get the above report. I'm going to guess that I need some
>>> real-time support from the kernel to make this work. Which
>>> brings me to
>>
>> this is not true. http://jackaudio.org/realtime_vs_realtime_kernel
>
> OK. That's a pleasant answer. :-)
>
> I added this:
>
> ::::::::::::::
> /etc/security/limits.d/93-audio_limits.conf
> ::::::::::::::
> # Increase priority of audio applications
> # maximum realtime priority
> @audio - rtprio 90
> # maximum locked-in-memory address space (KB)
> @audio - memlock 2000000
>
>
> Fedora's jack-audio-connection-kit-1.9.8-9.fc17.x86_64 package added this:
>
> ::::::::::::::
> /etc/security/limits.d/95-jack.conf
> ::::::::::::::
> # Default limits for users of jack-audio-connection-kit
>
> @jackuser - rtprio 70
> @jackuser - memlock 4194304
>
> @pulse-rt - rtprio 20
> @pulse-rt - nice -20
>
>> you *must* get these permissions correct ...
>
> By permissions, are you meaning
>
> crw-rw---- 1 root audio 10, 228 Oct 10 22:47 /dev/hpet
> crw-rw---- 1 root audio 254, 0 Oct 10 22:47 /dev/rtc0
>
> [kevinc #28] groups
> kevinc root adm disk wheel cdrom man floppy games audio users jackuser
>
>>> 3. Kernel with Real-Time Preemption... not found - not good
>>
>> not necessarily relevant. required in cases where the kernel and h/w are
>> cooperating (badly) to prevent low latency operation, but many people have
>> systems where this is not required.
>
> I'm having IRQ crowding issues, and I was headed at trying to
> get rtirq going in order to help this. I believe rtirq *does*
> require an RT kernel.
> http://wiki.linuxmusicians.com/doku.php?id=system_configuration#rtirq

Hi Kevin

the default values provided by jack in limits.d have been chosen to work
with the defaults in Fedora's rtirq package. You should only need to add
threadirqs to the kernel command line

regards,

Brendan

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Received on Fri Oct 12 16:15:02 2012