[LAU] eliminating xruns on 64-bit Arch ?

[Jeremy Jongepier]

On 12/14/11 15:42, Dave Phillips wrote:
> 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
>
>

Hello Dave,

So the correct settings get picked up, they should have otherwise you 
couldn't run JACK with your current settings.

>>>
>>> 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
>

Not a super-heavy DE. Did you try the latencytop tool? Could be helpful 
to figure out what's lagging. And did you try adjusting the swappiness 
of your system? And setting noatime for your filesystems?

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

Best,

Jeremy