[LAD] [ANNOUNCE] Safe real-time on the desktop by default; Desktop/audio RT developers, read this!

Fernando Lopez-Lezcano nando at ccrma.Stanford.EDU
Sun Jun 21 23:42:01 UTC 2009

On Mon, 2009-06-22 at 00:15 +0200, Lennart Poettering wrote:
> On Sun, 21.06.09 11:09, Paul Davis (paul at linuxaudiosystems.com) wrote:
> > I cannot imagine wanting to use this mechanism. You also seem to
> > have assumed that everyone agrees that SCHED_RR is the correct
> > policy, rather than SCHED_FIFO.  
> If people can make a good case for SCHED_FIFO, then fine, we can add
> that to rtkit.
> Personally, I believe that RR vs. FIFO is not so much a decision that the
> programmer should make. I think this is more a decision for the admin,
> because this influences fairness between consumers of RT.

It is, ultimately, a decision for the _user_ to make. RealtimeKit should
also take that into account. 

As a user doing critical audio, say, in a concert situation, I'd require
that my computer's realtime audio tasks can use 99.9% of the cpu for
short amounts of time. I don't care if the rest of the user processes
are momentarily slowed down (up to a point, of course). I would very
much care if my computer, due to a temporary overload, decides to a)
glitch the audio and b) demote the rt process to SCHED_OTHER
permanently. It looks like the RealtimeKit is designed to do exactly
that by default. 

If that is the case, how can I regain control of what I can do without
having to resort to extreme cases of root configuration file magic, etc,
etc (what RealtimeKit is supposed to avoid). 

-- Fernando

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