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

[Joakim Hernberg]

On Sun, 14 Feb 2016 17:42:01 -0500
"jonetsu at teksavvy.com" <jonetsu at teksavvy.com> wrote:

> On Sun, 14 Feb 2016 14:28:25 -0800 (PST)
> Len Ovens <len at ovenwerks.net> wrote:
> 
> > That doesn't look right. I am not sure that changing this would fix
> > your problem, but I prefer to have a different RTPRIO for anything
> > above 50.   
> 
> It has changed since that posting :)
> 
> RTIRQ_NAME_LIST="snd_ice1712"
> 
>   PID CLS RTPRIO  NI PRI %CPU STAT COMMAND
>   431 FF      90   - 130  1.6 S    irq/18-snd_ice1
>    47 FF      50   -  90  0.0 S    irq/9-acpi
>    77 FF      50   -  90  0.0 S    irq/23-ehci_hcd
>    78 FF      50   -  90  0.0 S    irq/23-ehci_hcd
>    79 FF      50   -  90  0.0 S    irq/43-xhci_hcd
>    80 FF      50   -  90  0.0 S    irq/44-xhci_hcd
>    81 FF      50   -  90  0.0 S    irq/45-xhci_hcd
>    82 FF      50   -  90  0.0 S    irq/46-xhci_hcd
>    83 FF      50   -  90  0.0 S    irq/47-xhci_hcd
>    84 FF      50   -  90  0.0 S    irq/48-xhci_hcd
>    86 FF      50   -  90  0.0 S    irq/12-i8042
>    87 FF      50   -  90  0.0 S    irq/1-i8042
>    88 FF      50   -  90  0.0 S    irq/8-rtc0
>   157 FF      50   -  90  0.0 S    irq/50-ahci
>   170 FF      50   -  90  0.0 S    irq/51-i915
>   420 FF      50   -  90  0.0 S    irq/52-mei_me
>   427 FF      50   -  90  0.0 S    irq/53-snd_hda_
>  1096 FF      50   -  90  0.0 S    irq/49-eth0
> 
> [ksoftirqs snipped]
> 
> I wonder if it makes a difference if the rtc is so low,  One of the
> web pages that was provided here mentions that rtc should be first.  

Most likely the RTC isn't used at all anymore, check how many times it
has fired with "cat /proc/interrupts".  One my system it fires exactly
once during bootup.

AFAIK, the only important configuration nowdays is to make sure that
the soundcard (or usb hub is connected to) is executed first, then JACK
(which automatically gives the priority of your audio processing
threads). So I'd suggest to run the soundcard interrupt at a high
priority, say 95-97 or so (leave 99 for the housekeeping threads).
Then run JACK at 80 (which will run your audio processing threads at
75).

-- 

   Joakim