On 12/21/05, Florian Schmidt <mista.tapas@xxxxxxx> wrote: > Well, rtlimits doesn't do this either. > > The mechanism to gain realtime privs and the worst case scheduling > latencies of the kernel are two completely different issues. > > For the former, there's the realtime-lsm and rtlimits which _only_ > enable a non root user to do what a root user could do anyways. > > For the latter, there's the -rt kernels, although the vanilla kernels > are quite usable these days, too. I see, this is exactly the kind of thing I was looking for, and now that I think about it, it makes total sense. Let me see if I understand it: rtlimits allows a normal user to preempt, but you must enable the preemption option in the kernel config in the first place for it to do any good. Is that it? > It is quite ok for most uses, especially when not going for ultra low > latencies (like 8 or 16 frames). Make sure you use the "(X) Preemptible > Kernel (Low-Latency Desktop)" setting though when building a vanilla > kernel (or make sure your distro builds it this way if you use a distro > provided kernel; check i.e. /proc/config.gz and/or write a mail to the > appropriate ML/maintainer). Again, this is apparently the part that must be "enabled" to see the full benefits of using rtlimits, correct? Once I've enabled this option (Preemptible Kernel), do I then have what you are referring to as a -rt kernel? > Also the -rt kernel, due to prioritizing the irq handler threads, > provides better RT "guarantees" if you want to call it that ;) I.e. > given that the scheduler works correct, and that you have setup the > priorities in your system correctly (and that jackd ant the clients are > well behaving RT programs), there's almost _no way_ that other system > activity might cause delays that produce xruns in turn, even with > ridiculously low latencies. I don't think that I am the type of user that needs that kind of low latency, I just need enough to do my basic home recordings. I think, in light of this, I might install DeMudi on my seperate partition; it might avoid all of this kernel business very easily. I still hate that I don't know how to do things myself, so any further comment is welcome. Thank you very much for your comments, Josh -- Josh Lawrence http://www.hardbop200.com
