Re: [linux-audio-user] Re: favorite window Manager for making music?

On Mon, 2006-02-20 at 13:57 -0800, thewade wrote:
> Quoting Jan Depner <eviltwin69@email-addr-hidden>:
>
> > On Mon, 2006-02-20 at 08:24 -0800, thewade wrote:
> >> Quoting Ismael Valladolid Torres <ivalladt@email-addr-hidden>:
> >> >
> >> > If you're trying to get the lowest latency posible it's dumb having a
> >> > desktop system that eats half your resources.
> >> >
> >>
> >> I think what Lee is saying is that with realtime-lsm (and ingo's
> >> spin-locking?), jackd, your audio apps, and limits.conf all set up
> >> right all processes bow to your audio apps. So audio will still get the
> >> lowest latency possible independant of other threads running on your
> >> machine, including the window manager. The screen may not refresh as
> >> frequently or be as responsive, but you should incur no addidional
> >> XRUNS from using one window manager over another.
> >> Am I right?
> >>
> >
> > This is all well and good but you're only talking about CPU. Disk
> > I/O is another story entirely. If your WM starts doing some I/O that
> > you weren't aware of you may get an xrun because you couldn't access the
> > disk in time. This is the reason that I kill syslogd before I record.
> > Granted, generally speaking you'll do OK due to the priority of your
> > process but disk I/O takes a certain amount of time and you can't
> > interrupt it once it's gone to the disk.
>
> I think you can tweak the disk write interupt length so that disk write
> sizes are smaller and more frequent, which would effectively solve this
> problem.
> I think you can do this in /etc/sysconfig/harddisks in Fedora.
> Syslogd can be usefull...
>

    Not when I'm recording someone else's band and xruns make
Linux/Ardour/JACK look bad. There's nothing happening on my system that
I need to know about that badly. Especially after the fact.

> There is a hard drive realtime audio howto somewhere on the net: I
> remember reading it somewhere... I think Takashi Iwa (I hope I spelled
> his name right) wrote something about it when he wrote that latency
> motior kernel module tool thingy.
>

    There's a bunch of information on that on my site (albeit outdated).
Tuning the disk drives is a must and it *will* help but there are
instances where the disk drive is busy and you can't get to it no matter
how well tuned it is. I prefer to minimize any chance of that. You
have to remember that unless you're running RTLinux or VXWorks (or DOS
or VMS) you're not running a hard real time system. Shit happens.

-- 
Jan 'Evil Twin' Depner
The Fuzzy Dice
http://myweb.cableone.net/eviltwin69/fuzzy.html
"As we enjoy great advantages from the invention of others, we should be 
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