[LAU] small/cheap devices that can run jackd?

[Luke Peterson]

I'm one of the folks performing through a netbook. A dell latitude 2100 --
the rubberized primary-school edition, 2gb ram and one of the atom chipsets.
Maybe now in the $300 range?

I use fluidsynth and bristol with alsa and jackd, setting various patches
across 8 midi channels, playing through an m-audio usb sound processor, with
one or sometimes two usb midi devices as controllers.

I custom-compiled a very lightweight rt kernel. I still use gnome, but turn
off networking to prevent memory usage spikes not related to music... and
keep a close eye on the available system memory and cpu while playing. Also
no holding bristol chords with more than 5 notes. :) I could probably get up
to 7 if I lost gnome, but I prefer the minimalist musical approach to
avoiding xruns. And I like to be able to use the dell's touchscreen to flip
through scanned charts in pdf when I forget what I'm supposed to be playing!

Cheers,
Luke

-----
Luke Peterson
- sent via mobile device -
On Oct 25, 2011 5:11 AM, "Jeremy Jongepier" <jeremy at autostatic.com> wrote:

> On 10/25/2011 10:44 AM, Renato wrote:
> > On Tue, 25 Oct 2011 10:20:18 +0200
> > Jeremy Jongepier <jeremy at autostatic.com> wrote:
> >
> >> True. I've set up the netbook to disable all services and unload all
> >> drivers I don't need when booting with a realtime kernel.
> >
> > for doing this you simply run a script which figures out the running
> > kernel with "uname"?
> >
>
> Hi Renato,
>
> Yes:
>
> if [ $(uname -r | cut -d "-" -f 3) = "realtime" ]
> then /path/to/startstudio
> fi
>
> And the 'startstudio' script looks like this:
>
> #!/bin/sh
>
> modprobe -r ppdev
> modprobe -r lp
> modprobe -r uvcvideo
> modprobe -r videodev
> modprobe -r ath9k
> modprobe -r r8169
> modprobe -r btusb
>
> /etc/init.d/bluetooth stop &
> /etc/init.d/cups stop &
> /etc/init.d/networking stop &
> /etc/init.d/network-manager stop &
> /etc/init.d/ondemand stop
>
> killall modem-manager
> killall wpa_supplicant
>
> modprobe snd-hrtimer
>
> echo -n performance > /sys/devices/system/cpu/cpu0/cpufreq/scaling_governor
>
> TASKLETPR=76
>
> ps -eLo pid,cmd | grep tasklet | grep -v grep | awk '{ system("chrt -f
> -p '$TASKLETPR' " $1)}'
>
> echo -n "0000:00:13.0" > /sys/bus/pci/drivers/ohci_hcd/unbind
>
> >> And it runs
> >> a light DE, rtirq and CPU scaling is set to performance. Also make
> >> sure your audio device isn't sharing an interrupt with something
> >> else. In my case the onboard soundcard shares an interrupt with a USB
> >> controller. I need to unbind the controller otherwise CPU load on the
> >> tasklets will quickly rise.
> >
> > what do you mean exactly by unbinding the controller? physically
> > removing it?
> >
>
> No, writing the ID of the controller to an unbind file, it's the last
> line in the startstudio script.
>
> > cheers,
> > renato
>
> Best,
>
> Jeremy
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> Linux-audio-user mailing list
> Linux-audio-user at lists.linuxaudio.org
> http://lists.linuxaudio.org/listinfo/linux-audio-user
>
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