[LAU] (Ardour) How to get rid of delay when recording ? - status so far

[jonetsu at teksavvy.com]

On Sat, 13 Feb 2016 16:01:57 -0500
"jonetsu at teksavvy.com" <jonetsu at teksavvy.com> wrote:

> It would be so nice to have no delay at all!

Here is what was done so far.  The test is with jackd -p 128 eg.:

/usr/bin/jackd -T -ndefault -dalsa -dhw:M1010LT -r44100 -p128 -n2

When playing an Ardour session, there is plenty of crackling noise
still.

kernel: 3.13.0-77-lowlatency

/etc/default/rtirq is:
#RTIRQ_NAME_LIST="rtc snd usb i8042"
RTIRQ_NAME_LIST="snd_ice1712"

% ./rtirq start
Setting IRQ priorities: start [snd_ice1712] irq=18 pid=547 prio=90: OK.

% cat /proc/irq/18/smp_affinity
f

% echo 2 > /proc/irq/18/smp_affinity

% cat /proc/interrupts 
        CPU0     CPU1     CPU2    CPU3       
  0:     28        0        0       0  edge      timer
  1:      3        0        0       0  edge      i8042
  4:      0        0        0       2  edge    
  8:      0        1        0       0  edge      rtc0
  9:      0        3        0       0  fasteoi   acpi
 12:      3        1        0       0  edge      i8042
 18: 476281   151882   127790   60568  fasteoi   snd_ice1712
 23:    117    12720     2133      42  fasteoi   ehci_hcd:usb1,

% ./rtirq status

  PID CLS RTPRIO  NI PRI %CPU STAT COMMAND
   87 FF      90   - 130  0.0 S    irq/8-rtc0
  547 FF      90   - 130  1.2 S    irq/18-snd_ice1

When playing an Ardour session, lots of these:

JackEngine::XRun: client = mixbus was not finished, state = Running
JackAudioDriver::ProcessGraphAsyncMaster: Process error