[PlanetCCRMA] Too many xruns w/Delta 66 on F7

[Paul Coccoli]

Hi all,

I've been running Planet CCRMA for years and have generally been happy
with it.  Since moving to Fedora 7, however, I can't get my jack
latency settings as low as I'd like.  I get periodic xruns (without
any jack apps running) at anything below 1024 frames and 2 periods.

The hardware is an Athlon 1800, 1G RAM, with a M-Audio Delta 66.  Same
hardware I've had for years, and I could swear I had better
performance with FC5 (and FC2, and RH9).

I've looked at everything I can think of:

I've got the latest Planet kernel:
paul at boon ~]$ uname -r
2.6.22.6-1.rt9.5.fc7.ccrmart

I bumped the PCI latency timer up on the ICE1712 chip (the Delta):
00:0a.0 Multimedia audio controller: VIA Technologies Inc. ICE1712 [Envy24] PCI
Multi-Channel I/O Controller (rev 02)
        Subsystem: VIA Technologies Inc. M-Audio Delta 66
        Flags: bus master, medium devsel, latency 248, IRQ 20

IRQ stuff looks fine to me (audio on IRQ 20):
[paul at boon ~]$ cat /proc/interrupts
           CPU0
  0:  272253996   IO-APIC-edge      timer
  1:          2   IO-APIC-edge      i8042
  6:          6   IO-APIC-edge      floppy
  7:          0   IO-APIC-edge      parport0
  8:          0   IO-APIC-edge      rtc0
  9:          0   IO-APIC-fasteoi   acpi
 12:          4   IO-APIC-edge      i8042
 14:     893299   IO-APIC-edge      libata
 15:    5410951   IO-APIC-edge      libata
 16:    1602810   IO-APIC-fasteoi   uhci_hcd:usb1, uhci_hcd:usb2,
uhci_hcd:usb3, ehci_hcd:usb4
 18:          2   IO-APIC-fasteoi   ohci1394
 19:    1374546   IO-APIC-fasteoi   eth0
 20:    3078836   IO-APIC-fasteoi   ICE1712
NMI:          0
LOC:  319262183
ERR:          0
MIS:          0

The only IRQ with a higher priority is the RTC on 8 (seems sensible):
[paul at boon ~]$ ps -e -o pid,cmd,pri | grep IRQ
   61 [IRQ-9]                      90
  304 [IRQ-12]                    104
  305 [IRQ-1]                     105
  322 [IRQ-16]                    110
  345 [IRQ-14]                     90
  346 [IRQ-15]                     90
  673 [IRQ-6]                      90
  910 [IRQ-8]                     120
  942 [IRQ-18]                     90
  948 [IRQ-7]                      90
 1034 [IRQ-20]                    115
 1498 [IRQ-19]                     90

Jackd priority looks right (I assume the 100 is the watchdog, 90 is
the audio thread?):
[paul at boon ~]$ ps -mo pid,cmd,pri -C jackd
  PID CMD                         PRI
31851 jackd -R -P50 -dalsa -dhw:0   -
    - -                            19
    - -                            19
    - -                            19
    - -                           100
    - -                            90

QJackctl is using this:
[paul at boon ~]$ cat .jackdrc
jackd -R -P50 -dalsa -dhw:0 -r44100 -p256 -n2

And yet, xruns:
21:40:37.506 Startup script...
21:40:37.512 artsshell -q terminate
JACK tmpdir identified as [/dev/shm]
21:40:37.877 Startup script terminated with exit status=256.
21:40:37.879 JACK is starting...
21:40:37.884 jackd -R -P50 -dalsa -dhw:0 -r44100 -p256 -n2
21:40:37.903 JACK was started with PID=32405 (0x7e95).
jackd 0.103.0
Copyright 2001-2005 Paul Davis and others.
jackd comes with ABSOLUTELY NO WARRANTY
This is free software, and you are welcome to redistribute it
under certain conditions; see the file COPYING for details
JACK compiled with System V SHM support.
loading driver ..
Enhanced3DNow! detected
apparent rate = 44100
creating alsa driver ... hw:0|hw:0|256|2|44100|0|0|nomon|swmeter|-|32bit
control device hw:0
configuring for 44100Hz, period = 256 frames, buffer = 2 periods
ALSA: final selected sample format for capture: 32bit little-endian
ALSA: use 2 periods for capture
ALSA: final selected sample format for playback: 32bit little-endian
ALSA: use 2 periods for playback
21:40:40.166 Server configuration saved to "/home/paul/.jackdrc".
21:40:40.168 Statistics reset.
21:40:40.169 Client activated.
21:40:40.171 Audio connection change.
21:40:40.199 Audio connection graph change.
JACK tmpdir identified as [/dev/shm]
Enhanced3DNow! detected
21:40:40.374 Audio active patchbay scan...
21:41:11.971 XRUN callback (1).
delay of 11622.000 usecs exceeds estimated spare time of 5619.000; restart ...
**** alsa_pcm: xrun of at least 0.054 msecs
21:41:21.684 XRUN callback (2).

Any help would be appreciated.  What have I missed?