scheduling priority not working?

Sergey 'DoubleF' Zaharchenko doublef at
Sun Feb 29 05:28:42 PST 2004

On Sun, 29 Feb 2004 19:07:12 +0800
"Zhang Weiwu" <weiwuzhang at> probably wrote:

> Sergey 'DoubleF' Zaharchenko wrote:
> >There's more than nice to change priority; for example, check out
> >rtprio(1) and idprio(1). Just FYI.
> >
> GREAT TOOL rtprio(1) is. Now I can run 'rtprio 5 mpg321 *.mp3' it produce
> very smooth sound.

Are you running the MP3 player as root? I wouldn't recommend it. I'd
make a script using sudo and su'ing back to myself just after the
priority change. FWIW this is what I use for listening to my music:

sudo /usr/sbin/rtprio 5 /usr/bin/su df -c "/usr/local/bin/splay -s -2 /home/df/music/*" &

Of course, I changed the suders file accordingly and wrote a script
`mus' which includes the quoted line.

rtprio is really powerful, and that's why it may be a bit
dangerous. If a program which has run-time priority gets into a large
amount of calculations, or into a busy-wait loop, all other programs
will starve (the machine will appear hung). If you don't trust your
MP3 player (or any program you set to have run-time priority) to be
bullet-proof, you should think twice before using rtprio. Not that I
have found many misbehaving programs, but I sometimes happen to write

Truthful, adj.:
	Dumb and illiterate.
		-- Ambrose Bierce, "The Devil's Dictionary"
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