Re: Re: csoundtekno Digest, Vol 2, Issue 9

This really depends on just how low you want. I have gotten excellent results
compared to windoze using the gentoo-dev sources for 2.6.8 with all the
low-latency/pre-emptions options turned on. If we run as root and use the
--sched  option for csound with all displays turned off, we can push it very
hard with very low latency, and still just about do anything on the desktop
without any hiccups. 

One key to this though, is that you *must* consider cpu spikes when designing
your csound ensemble. If you suddenly spike over 100%, your system will just
lock up entirely until cpu use goes down again. What we did was make sure that
whenever possible any instruments that might be on, are always on, with just an
inaudible ouput. ( Ie the fancy feedback delays and stuff are always chugging
away, with just an inaudible 20khz sine wave going through them ). This made a
very large difference for stabilizing load. I dunno why, but adding the
inaudible sine wave in all mixer channels dropped cpu spikes and even overall
use significantly.

Iain


> I'm not sure if it's really that easy given all the talk, tests and 
> conflicting results mentioned on LAD. They're trying custom real-time 
> kernel patches, which AFAIK are necessary for low latency audio work.
> Brian, has the procudure you describe produced satisfactory results 
> using things like jack and pd?
> 
> Andres
> 
> > After doing "make menuconfig", select "Processor Types and Features", and
> > then select "Preemptable Kernel".
> > 
> > This is the 2.6 equivalent to low latency in 2.4
> 
> 
> 
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