Subject: Re: [linux-audio-dev] Realtime restrictions when running multipleaudioapps .. Was: Re: disksampler ...
From: Erik Steffl (esteffl_AT_pbi.net)
Date: Tue Jul 18 2000 - 20:18:07 EEST
Benno Senoner wrote:
>
> On Tue, 18 Jul 2000, Erik Steffl wrote:
>
> > >
> > > Thus, a realtime soundserver must somehow allow in-process execution, so
> > > that the realtime parts of apps can be gathered inside the soundserver.
> >
> > crash of an application that runs inside of soundserver would crash
> > soundserver, which in turn causes the crashes of all sound applications.
> > how do you get around that?
>
> you have to live with that and in the professional world, a crash of a
> single soundmodule means making your recording useless.
>
> For realtime we simply have to live with this crash-problem.
> At least we do not get a complete system lockup but only a simple
> segfault.
I don't think it's as simple as that. most of the programs today have
some sound support, for example all gnome programs (as far as I can
tell, I checked the games, pan (news reader) and other gnome programs)
have sound support. so if the sound server crashes, all of these
programs crash. for a desktop system (including music studio system)
it's almost the same as system crash.
I already had somewhat related problem, when i had no sound support,
most programs ran, but as soon as I started alsa without oss support
conmfigured, all gnome programs stopped working (well, I can still use
--disable-sound to make them work). I mean these things affect the whole
system, even though they are in user space.
we (=it's quite often in linux community) criticize MS for putting
everything in kernel just for runtime performance (think video drivers
etc.) and now we're talking about doing exactly the same thing in linux.
the sound server segfault is not simple segfault, as long as all the
apps are using it. and from the discussion it looks like they would have
to since the sound server would have exclusive access to audio devices
in/dev.
> David said you could add some memory protection to via a kernel module.
> But that is too tricky IMHO.
that might be a way to go... if it's possible.
...
> But no one requires you to convert/run all your apps within this model.
> Only the high-end ones will require so.
> (I think Cubase + ReWire on windows does it in a similar way)
as I understood the discussion the sound server would be for
everybody. if only few apps would use it then you would not be able to
run any other audio apps while you're running the sound server. that
does not make much sense. the point of the sound server was to be able
to use more then one app to access the audio.
erik
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