'Twas brillig, and marcin at saepia.net at 20/06/11 14:55 did gyre and gimble:
> Hi,
>
> I am trying to figure out why PulseAudio daemon drops a few samples
> from time to time.
>
> I got a few null sinks combined with each other by loopbacks. Then my
> applications gather sound from their .monitors. Sounds simple.
>
> I quickly came to idea that running PulseAudio in RT mode could help.
> I encountered a lot of problems, because:
> - my PA daemons are started at the boot time (but as normal users!)
> and start-stop-daemon know nothing about /etc/security/limits.conf, so
> I got troubles with setting limits for them without setting RT limits
> for the whole system,
> - PA daemon tries to communicate to rtkit and rtkit tries to
> communicate to PolicyKit which becomes the next dependency for me
> etc...
>
> During the process I started to investigate pulseaudio & rtkit source
> code and I found something strange.
>
> e.g. combine module tries to acquire realtime priority during thread
> initialization:
>
> static void thread_func(void *userdata) {
> struct userdata *u = userdata;
>
> pa_assert(u);
>
> pa_log_debug("Thread starting up");
>
> if (u->core->realtime_scheduling)
> pa_make_realtime(u->core->realtime_priority+1);
>
> pa_thread_mq_install(&u->thread_mq);
>
>
> while e.g. NULL sink doesn't:
>
> static void thread_func(void *userdata) {
> struct userdata *u = userdata;
>
> pa_assert(u);
>
> pa_log_debug("Thread starting up");
>
> pa_thread_mq_install(&u->thread_mq);
>
>
>
> What is the reason for that?
>
> For me, it means that even if I solve all problems mentioned above, my
> NULL sinks still wouldn't be using realtime scheduler policy?
>
> Shouldn't it be fixed?
Probably this is just because no one has had a reason for this
before.... it's certainly worth thinking about if it does solve your
problem.
Col
--
Colin Guthrie
gmane(at)colin.guthr.ie
http://colin.guthr.ie/
Day Job:
Tribalogic Limited [http://www.tribalogic.net/]
Open Source:
Mageia Contributor [http://www.mageia.org/]
PulseAudio Hacker [http://www.pulseaudio.org/]
Trac Hacker [http://trac.edgewall.org/]
