Scheduling Issues with Multimedia Apps

[Miguel Mendez]

On Sun, 14 Nov 2004 02:26:40 -0800
"Loren M. Lang" <lorenl at alzatex.com> wrote:

Hi,

> Now to try and solve this I tried to set xmms to use realtime priority
> and made it setuid root.  According to top it's running at priority 20
> nice -76 so it seems to be running realtime, but portupgrade can still
> interrupt the audio occasionally.  I've tried nicing portupgrade
> before,
[...]
> amount of time.  If their scheduled apropriately there should be no
> conflicts, I've never really had this issues with linux, AFAIK.  Is
> there any better way to fix this?

Some person recently asked this in freenode's #FreeBSD irc channel, and
the solution that worked for him was to increase xmms's buffer. Go the
preferences menu, Audio I/O plugins, increase the buffer size and see if
it makes a difference. You don't mention what kind of disks you use, but
I guess they're IDE disks. Make sure DMA is working. I usually read my
mp3 files from a NFS server and they never skip, even when the machine
is doing heavy i/o (e.g. unpacking firefox) and/or under load (avg load of
10), but I've noticed audio skips when the mp3 file was on a local disk
that was being currently in use. I don't think increasing xmms's priority
will fix the problem.

Why you don't see that problem in Linux could be due to the anticipatory
i/o scheduler in 2.6.

HTH,
-- 
	Miguel Mendez <flynn at energyhq.es.eu.org> | Extreme ways are back again
	http://www.energyhq.es.eu.org            | Extreme places I didn't know
	PGP Key: 0xDC8514F1                      | I broke everything new again
	Note: All HTML mail goes to /dev/null    | Everything that I'd owned

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