[PlanetCCRMA] root vs capabilities

R Parker rtp405@yahoo.com
Tue Jun 1 10:11:02 2004

Hi Fernando,

--- Fernando Pablo Lopez-Lezcano
<nando@ccrma.Stanford.EDU> wrote:
> > Linux stepdaddy 2.4.26-1.ll.rh90.ccrma #1 Fri Apr
> 16
> > 21:56:56 PDT 2004 i686 athlon i386 GNU/Linux
> > 
> > [root@stepdaddy master03]# cat
> > /proc/sys/kernel/lowlatency
> > 1
> > 
> > I've been experiencing a greater number of xruns
> while
> > running jack, ardour and jamin as a normal user
> than I
> > see while working as root.
> >
> > I am puzzled. How could there be a differnce
> between
> > the two users?
> > 
> > If I understand capabilities, then in the context
> of
> > my experience it's irrelevant what desktop I use
> (KDE)
> > and what processes may be running as a result.
> Bottom
> > line, everytime I attempt to work as a normal user
> I
> > give up and run everything as su because xruns and
> > disconnections from jack make it impossible to
> work.
> How are you starting jack? What does it say when it
> starts? As a normal
> user you should start it with the jackstart command
> and the "-R" flag,
> like this:
>   jackstart -R -d alsa -d hw
> (with whatever parameters work with your card, of
> course). 

/usr/bin/jackstart -R -p512 -dalsa -dhw:0 -r44100
-p256 -n2

that's the .jackdrc file that qjackctl uses.

Fernando, I have no hard evidence but running lower
than -p512 used to be normal for me. I swear I used to
run -p128 and -p256 with rock solid performance.
During the last several months, i usually run -p1024.
I don't know what that means. Part of me wonders if
something has changed in jackd. I guess it has
undergone changes. Understanding these things is
somewhat beyound me.

A couple things that have changed for me since the
rock solid performance days are the use of CCRMA
rather than Gentoo and I changed from an nvidia to an
ATI radeon 9500 pro display card. I've installed the
ATI drivers and it doesn't seem to make much

I suppose there could be something to the switch from
Gentoo to CCRMA but wouldn't the issues be centric to
the kernel and not the distribution?

I guess compiling some different kernel versions isn't
an unreasonable direction for me to experiement with.
But I don't want to learn how to use rpmbuild in the
ccrma environment. :) Just kidding! 


> -- Fernando

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