[linux-audio-user] xruns from ardour + softsynths

Hi

I played a bit with ardour to the extend that I ended up with 12 tracks
of backing vocals (playing at the same time) + a lead vocal + some talk
+ zynaddsubfx (running two pads + bass) + specimen (drums) + ams (lead)
+ seq24 for midi.

This is too much for my setup, I get audible xruns every now and then
(just after loading the song often, after a while about every minute,
with no window activity) and qjackctl reports them all the time. However
the cpu usage is below 50% so I'm led to believe that with some fine
tuning it should be possible.

My computer is a Pentium M 1.6 w 1G ram, 100G 7200 RPM HD running
xubuntu/dapper/6.06 and I use the (I know shitty) onboard i8x0 .
Basically all I did was:

echo @audio - rtprio 99 >> /etc/security/limits.conf
echo @audio - memlock 250000 >> /etc/security/limits.conf
echo @audio - nice -10 >> /etc/security/limits.conf

I think my soundcard works at 48000 hz, but I run jack at 44100 because
of previous (now resolved) problems with zynaddsubfx. Could this be the
cause of my problems?

hdparms says:
root@email-addr-hidden:~# hdparm /dev/hda
/dev/hda:
  multcount = 0 (off)
  IO_support = 0 (default 16-bit)
  unmaskirq = 0 (off)
  using_dma = 1 (on)
  keepsettings = 0 (off)
  readonly = 0 (off)
  readahead = 256 (on)
  geometry = 16383/255/63, sectors = 195371568, start = 0

And:
root@email-addr-hidden:~# cat /proc/interrupts
            CPU0
   0: 1435743 XT-PIC timer
   1: 3861 XT-PIC i8042
   2: 0 XT-PIC cascade
   3: 28534 XT-PIC irda0
   7: 0 XT-PIC parport0
   8: 3 XT-PIC rtc
   9: 916321 XT-PIC acpi
  11: 2391090 XT-PIC uhci_hcd:usb1, uhci_hcd:usb2,
uhci_hcd:usb3, ehci_hcd:usb4, ath0, yenta, Intel 82801DB-ICH4, yenta,
eth0, radeon@email-addr-hidden:0000:01:00.0
  12: 2488 XT-PIC i8042
  14: 82500 XT-PIC ide0
  15: 98767 XT-PIC ide1
NMI: 0
LOC: 0
ERR: 0
MIS: 0

This is how jackd is setup (run through qjackctl):
atte@email-addr-hidden:~$ cat .jackdrc
/usr/bin/jackd -v -R -P65 -dalsa -dhw:0 -r44100 -p256 -n2 -S

Any ideas?

-- 
peace, love & harmony
Atte