Re: [Rakarrack-users] Error: cannot use real-time scheduling (FIFO at priority -4)

[Carlos s. <csa...@gm...>]

You're totally right, Ryan. I wrote my email in a hurry and forget about
writing some necessary context info that is mandatory (I should remembered
it by now for my own experience ;) ).

This is kind of a regular workflow when I run Rakarrack on that device:

* I switch on the device and Musix starts (I'm running now Musix beta 3
(Debian Squeeze) with some 3.0 and 3.2 RT kernels, but I think this is not
relevant for the matter)

* I or some script runs Qjackctl that starts Jack with RT configuration
    - usually with my external Edirol UA25 audio interface that performs
great

* I or some script runs Rakarrack(RK)
    - it's configured optimed for the UMPC capabilities: low values for
Upsampling and Harm. Quality, and Recognize Note Optimization set to Guitar
    - my scripts run now RK adding "2>some-error-file.txt" to log info for
debugging purposes
    - given my latelly crashes I run RK with processing unabled at the
start and then I use presets that the device can stand.

* Then, maybe I or some script runs additional "light" programs
(Freewheeling most of the times) that don't overload CPU and leave room for
RK processing

So now:
* Does it happen for every preset?
No. As you mention, I know the limitations of the device and, on this kind
of devices, I don't use presets as Rodent Airlines or others CPU intense. I
try to select/filter the stock presets that it can handles with RT.
I have some presets of my own and several presets used as pedalboards (10
discrete pedals to switch on and off) as well.

* Does it always happen on this machine?
No. It doesn't happen all the time and it doesn't crash always with the
same preset. i.e. sometimes I enable processing and the Harmonizer or
Sustainer and it keeps on, and others don't and it shuts down itself.

* Does this happen with other jack programs, or only rakarrack?
Just yesterday I run Freewheeling with "2>some-error-file.txt" and,
surprise!, the error was:
*"
cannot use real-time scheduling (FIFO at priority -4) [for thread
-1261438096, from thread -1261438096] (22: Invalid argument)
zombified - calling shutdown handler
"*
So it seems that is a general and localized cause, but now I doubt if the
problem is related to jack configuration or something else, but the thing
is that I've jammed with no problems for some time with the same jack
configuration for RT with the external audio interface (relevant
parameters: RT enabled, Tolerant mode enabled, 256 frames, 2 periods)

Please tell me if you need anything else.
Thanks.


2012/5/9 Ryan Billing <ry...@gm...>

> **
> Probably a first question to ask is,
> Does it happen for every preset?
>
> For example, I think the first preset "Rodent Airlines" uses a lot of CPU
> (40% on my 3Ghz Pentium 4).  So, try some different presets, for example,
> start rakarrack with a preset that you know is low cpu.  This might help to
> narrow it down.
>
> Another question, does it always happen on this machine?  Do you have jack
> started first, or do you start rakarrack without jack and let rakarrack
> start jack?
>
>
> Does this happen with other jack programs, or only rakarrack?
>
> Perhaps answering those questions will bring us closer.  Of course, using
> gdb may help to narrow the problem to something specific.
>
> Ryan
>
>
>
> On 05/08/2012 08:46 AM, Carlos sanchiavedraz wrote:
>
> Hi rakarrakers.
>
> I keep on testing Musix on various portable and not so powerful devices. I
> get this error (on a txt file using "2>some-error-file.txt") sometimes when
> enabling the FX processing on a UMPC[1]:
>
> "
> rakarrack 0.6.1 - Copyright (c) Josep Andreu - Ryan Billing - Douglas
> McClendon - Arnout Engelen
> Try 'rakarrack --help' for command-line options.
> cannot use real-time scheduling (FIFO at priority -4) [for thread
> -1267381392, from thread -1267381392] (22: Invalid argument)
> "
> I would like to know why and when this happens to see if I can stabilized
> the environment. I'm using it as an FX processor and live-looping system
> instead of a pedalboard.
>
> Thanks in advance, as always.
>
>
> [1] Ultra Mobile PC with this specs for the purpose
>
>     CPU type: Intel Atom (Silverthorne)
>     CPU speed: Z520, 1.33Ghz
>
> --
> Carlos sanchiavedraz
> * Musix GNU+Linux
>   http://www.musix.es
>
>
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-- 
Carlos sanchiavedraz
* Musix GNU+Linux
  http://www.musix.es