Mixxx looses realtime priority after switching audio Buffer

[Daniel Schürmann]

This was tested with ubuntu precise amd64 and Mixxx master 3499.

Test:

start Mixxx

$ ps -Leo pid,tid,class,rtprio,priority,stat,comm,wchan | grep mixxx
 3966 3966 TS - 20 Sl mixxx poll_schedule_timeout
 3966 3970 TS - 20 Sl mixxx futex_wait_queue_me
 3966 3971 TS - 20 Sl mixxx futex_wait_queue_me
 3966 3977 TS - 20 Sl mixxx futex_wait_queue_me
 3966 3978 TS - 20 Sl mixxx futex_wait_queue_me
 3966 3979 IDL 0 20 Sl mixxx futex_wait_queue_me
 3966 3980 TS - 20 Sl mixxx poll_schedule_timeout
 3966 3981 FF 82 -83 Sl mixxx poll_schedule_timeout

change Audio Buffer Size

$ ps -Leo pid,tid,class,rtprio,priority,stat,comm,wchan | grep mixxx
 3966 3966 TS - 20 Sl mixxx poll_schedule_timeout
 3966 3970 TS - 20 Sl mixxx futex_wait_queue_me
 3966 3971 TS - 20 Sl mixxx futex_wait_queue_me
 3966 3977 TS - 20 Sl mixxx futex_wait_queue_me
 3966 3978 TS - 20 Sl mixxx futex_wait_queue_me
 3966 3979 IDL 0 20 Sl mixxx futex_wait_queue_me
 3966 3980 TS - 20 Sl mixxx poll_schedule_timeout
 3966 3996 FF 1 -2 Sl mixxx poll_schedule_timeout

Thread 3981 with rtprio of 82 is gone and a new thread with rtprio 1 is issued.

$ cat /etc/security/limits.d/audio.conf
# Provided by the jackd package.
#
# Changes to this file will be preserved.
#
# If you want to enable/disable realtime permissions, run
#
# dpkg-reconfigure -p high jackd

@audio - rtprio 95
@audio - memlock unlimited
@audio - nice -19

By the way: I have noticed that changes limits requires a system restart.

[RJ Skerry-Ryan (rryan)]

Hm! Good catch. We should clear SoundDevicePortAudio::m_bSetThreadPriority
on close().

On Mon, Jul 1, 2013 at 4:50 AM, Daniel Schürmann <<email address hidden>
> wrote:

> Public bug reported:
>
> This was tested with ubuntu precise amd64 and Mixxx master 3499.
>
> Test:
>
> start Mixxx
>
> $ ps -Leo pid,tid,class,rtprio,priority,stat,comm,wchan | grep mixxx
> 3966 3966 TS - 20 Sl mixxx poll_schedule_timeout
> 3966 3970 TS - 20 Sl mixxx futex_wait_queue_me
> 3966 3971 TS - 20 Sl mixxx futex_wait_queue_me
> 3966 3977 TS - 20 Sl mixxx futex_wait_queue_me
> 3966 3978 TS - 20 Sl mixxx futex_wait_queue_me
> 3966 3979 IDL 0 20 Sl mixxx futex_wait_queue_me
> 3966 3980 TS - 20 Sl mixxx poll_schedule_timeout
> 3966 3981 FF 82 -83 Sl mixxx poll_schedule_timeout
>
> change Audio Buffer Size
>
> $ ps -Leo pid,tid,class,rtprio,priority,stat,comm,wchan | grep mixxx
> 3966 3966 TS - 20 Sl mixxx poll_schedule_timeout
> 3966 3970 TS - 20 Sl mixxx futex_wait_queue_me
> 3966 3971 TS - 20 Sl mixxx futex_wait_queue_me
> 3966 3977 TS - 20 Sl mixxx futex_wait_queue_me
> 3966 3978 TS - 20 Sl mixxx futex_wait_queue_me
> 3966 3979 IDL 0 20 Sl mixxx futex_wait_queue_me
> 3966 3980 TS - 20 Sl mixxx poll_schedule_timeout
> 3966 3996 FF 1 -2 Sl mixxx poll_schedule_timeout
>
>
> Thread 3981 with rtprio of 82 is gone and a new thread with rtprio 1 is
> issued.
>
>
> $ cat /etc/security/limits.d/audio.conf
> # Provided by the jackd package.
> #
> # Changes to this file will be preserved.
> #
> # If you want to enable/disable realtime permissions, run
> #
> # dpkg-reconfigure -p high jackd
>
> @audio - rtprio 95
> @audio - memlock unlimited
> @audio - nice -19
>
> By the way: I have noticed that changes limits requires a system
> restart.
>
> ** Affects: mixxx
> Importance: Undecided
> Status: New
>
> --
> You received this bug notification because you are a member of Mixxx
> Development Team, which is subscribed to Mixxx.
> https://bugs.launchpad.net/bugs/1196449
>
> Title:
> Mixxx looses realtime priority after switching audio Buffer
>
> To manage notifications about this bug go to:
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>

[Daniel Schürmann (daschuer)]

Thank you for your hint! That was actualy the fix.

Committed to master 44cfe127f7 r3510

[Swiftb0y (swiftb0y)]

Mixxx now uses GitHub for bug tracking. This bug has been migrated to:
https://github.com/mixxxdj/mixxx/issues/7087