[LAU] eliminating xruns on 64-bit Arch ?

[Dave Phillips]

On 12/14/2011 08:58 AM, Jeremy Jongepier wrote:
> On 12/14/11 13:55, Dave Phillips wrote:
>> The relevant entries in /etc/security/limits.conf
>>
>>      @audio          -       rtprio          99
>>      @audio          -       nice           -10
>>      @audio          -       memlock         unlimited
>>
>
> You could check /etc/security/limits.d/99-audio-conf
> I wonder though if both files exist if they don't conflict. What does 
> ulimit -r -m output?
>

It checks out:

     [dlphilp at BigBlack ~]$ ulimit -r -m
     real-time priority              (-r) 99
     max memory size         (kbytes, -m) unlimited


>>
>> The hardware is an M-Audio Delta 66 system, with a separate preamp. Some
>> relevant JACK (0.121.3) settings :
>>
>>      /usr/bin/jackd -P89 -t5000 -dalsa -dhw:0 -r48000 -p128 -n2 -Xseq
>>
>
> The seq driver can cause xruns. You can rule it out as a possible 
> cause by using a2jmidid.
>

Ah, okay, it's removed. I'll test later this afternoon, can't use the 
recorder at the moment.


>> I usually get two or three xruns per half-hour session, as compared to 0
>> with 64 Studio. Btw, I'm not comparing the distros, just the performance
>> stats. I have no interest in returning to older systems, but I have much
>> interest in improving the ones I'm running now.
>>
>> This bothers me :
>>
>>      [dlphilp at BigBlack etc]$ cat /proc/interrupts
>>                  CPU0
>>         0:         50   IO-APIC-edge      timer
>>         1:          4   IO-APIC-edge      i8042
>>         7:          1   IO-APIC-edge      parport0
>>         8:          2   IO-APIC-edge      rtc0
>>         9:          0   IO-APIC-fasteoi   acpi
>>        12:          6   IO-APIC-edge      i8042
>>        14:          0   IO-APIC-edge      pata_amd
>>        15:      27164   IO-APIC-edge      pata_amd
>>        16:     788897   IO-APIC-fasteoi   ICE1712, nvidia <---- Ouch !!!
>>        17:        144   IO-APIC-fasteoi   firewire_ohci
>>        20:      49995   IO-APIC-fasteoi   ohci_hcd:usb2
>>        21:      87877   IO-APIC-fasteoi   sata_nv
>>        22:       2124   IO-APIC-fasteoi   sata_nv, hda_intel
>>        23:      82436   IO-APIC-fasteoi   ehci_hcd:usb1, eth0
>>
>> Yep, that's my video card. Can I reassign the IRQ - preferably via
>> software - for one of those devices ?
>
> No, afaik only if your system supports MSI and it looks like it 
> doesn't (unless you didn't post the whole output). But I'm no expert 
> on this so I could be mistaken. You could try swapping ports for the 
> ICE1712.
>

I'm considering it. IIRC there are only two or three PCI slots on the 
mobo, and the nVidia card is in a PCIe slot.


>
>> know about the rtirq script but there seems to little information
>> regarding its use with a kernel such as mine (Rui ?).
>
> With your current non-rt kernel you have to use the threadirqs kernel 
> option. From then on you could install rtirq from AUR though that's 
> not the most recent version so you might have to modify the PKGBUILD.
>

I planned on using the latest from Rui's site, it's dated October 2011.


>
>
> The 3.0-rt kernel from AUR works amazingly well afaics, but I didn't 
> stretch test it yet.


I'll check it out asap.


>
> What DE are you using?

Xfce4

Thanks for the suggestions, Jeremy. I'm going to run some tests now.

Best,

dp