Arch Linux

Dieter@be

Forum Fellow

From: Belgium

Registered: 2006-11-05

Posts: 2,001

Website

Using the same system for lowlatency pro-audio and "normal" stuff?

On both my main pc and laptop i want to do:

- the usual stuff: plenty of "office work", occasionally 3d games (nvidia binary driver),... light power consumption is important (i also have cpu throttling here etc)
- pro-audio: very lowlatency stuff.

As far as i know, the second requires a RT kernel, but the RT kernel is not suited for the power requirements of the day to day usage in point 1. (right?)
I have nothing against doing a reboot to switch kernels, so i guess having both kernels alongside is the way to go.  At least it's simpler then having 2 separate arch installs and sharing /home or something.

But is this doable?  I found out for example that it's easy to install both kernels alongside each other, but I need 2 nvidia drivers, because the kernels are different versions.  And I noticed pacman does not allow you to install 2 different nvidia drivers (nvidia-173xx and nvidia-rt) alongside each other, even though they install files in different places.

Any tips? thanks

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< Daenyth> and he works prolifically
4 8 15 16 23 42

thisoldman

Member

From: Pittsburgh

Registered: 2009-04-25

Posts: 1,172

Re: Using the same system for lowlatency pro-audio and "normal" stuff?

You suggest having two different hardware profiles, much like the difference between a working kernel and a failsafe kernel.  It seems it should be possible.

But...

My experience has been that "magical" moments with music are not repeatable. You have just one chance to get it right. Do you want to risk not getting that once-in-a-lifetime take because of "technical difficulties?"

For audio recording, editing and playback, the safest method is to keep the setup as minimal as possible: go with only what you truly need. Disable cpu frequency utilities, sleep and hibernation modes, screensavers, cron jobs, bluetooth, even networking. You fight dropouts, clicks and hums from external equipment, why expose your sound to the avoidable ones from within the computer, from its software and from unused accessories? I would use two separate installations and some shared data directories.

Your proposal is an interesting technical exercise. I just don't think I could bear the avoidable failures sure to come along the way.

skottish

Forum Fellow

From: Here

Registered: 2006-06-16

Posts: 7,942

Re: Using the same system for lowlatency pro-audio and "normal" stuff?

My experience has been that "magical" moments with music are not repeatable. You have just one chance to get it right. Do you want to risk not getting that once-in-a-lifetime take because of "technical difficulties?"

For audio recording, editing and playback, the safest method is to keep the setup as minimal as possible: go with only what you truly need. Disable cpu frequency utilities, sleep and hibernation modes, screensavers, cron jobs, bluetooth, even networking. You fight dropouts, clicks and hums from external equipment, why expose your sound to the avoidable ones from within the computer, from its software and from unused accessories? I would use two separate installations and some shared data directories.

Welcome to the forums. This is an absolutely brilliant post. I remember a Keyboard Magazine article with Peter Gabriel years ago when they talked to him about his studio. He's setup to turn on all of his electronic gear and to automatically start recording with one button. It seems to working out alright for him.

ngoonee

Forum Fellow

From: Between Thailand and Singapore

Registered: 2009-03-17

Posts: 7,356

Re: Using the same system for lowlatency pro-audio and "normal" stuff?

Concerning nvidia, what you should do is download the PKGBUILDs to your machine, create a new PKGBUILD with a new name for the new kernel.

For example, I have two PKGBUILDs, one for 2.6.30-ARCH and one for 2.6.29-ice, whenever kernel updates I just rerun makepkg -i on those.

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Allan-Volunteer on the (topic being discussed) mailn lists. You never get the people who matters attention on the forums.
jasonwryan-Installing Arch is a measure of your literacy. Maintaining Arch is a measure of your diligence. Contributing to Arch is a measure of your competence.
Griemak-Bleeding edge, not bleeding flat. Edge denotes falls will occur from time to time. Bring your own parachute.

Dieter@be

Forum Fellow

From: Belgium

Registered: 2006-11-05

Posts: 2,001

Website

Re: Using the same system for lowlatency pro-audio and "normal" stuff?

You suggest having two different hardware profiles, much like the difference between a working kernel and a failsafe kernel.  It seems it should be possible.

But...

My experience has been that "magical" moments with music are not repeatable. You have just one chance to get it right. Do you want to risk not getting that once-in-a-lifetime take because of "technical difficulties?"

For audio recording, editing and playback, the safest method is to keep the setup as minimal as possible: go with only what you truly need. Disable cpu frequency utilities, sleep and hibernation modes, screensavers, cron jobs, bluetooth, even networking. You fight dropouts, clicks and hums from external equipment, why expose your sound to the avoidable ones from within the computer, from its software and from unused accessories? I would use two separate installations and some shared data directories.

Your proposal is an interesting technical exercise. I just don't think I could bear the avoidable failures sure to come along the way.

I'm a drummer. if i come up with a part I surely can remember it for 2 minutes

Your stuff about minimalism is very interesting. I think that can easily be done by putting something like this in /etc/rc.conf (after all, afaik this file gets sourced, not parsed)

if [[ `uname -r` ~= '-rt' ]]
then
DAEMONS=(syslog-ng hal network crond fam alsa jackd @timidity++)
MODULES=(..)
else
DAEMONS=(syslog-ng hal network netfs crond fam @openntpd @autofs alsa mpd @scrobby @sshd @timidity++ <insert more fancy things here>)
MODULES=(...)
fi

and probably something similar in .xinitrc (which i use to start my screensaver and desktop apps)

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< Daenyth> and he works prolifically
4 8 15 16 23 42

Dieter@be

Forum Fellow

From: Belgium

Registered: 2006-11-05

Posts: 2,001

Website

Re: Using the same system for lowlatency pro-audio and "normal" stuff?

Concerning nvidia, what you should do is download the PKGBUILDs to your machine, create a new PKGBUILD with a new name for the new kernel.

For example, I have two PKGBUILDs, one for 2.6.30-ARCH and one for 2.6.29-ice, whenever kernel updates I just rerun makepkg -i on those.

so this means you have to rebuild and reinstall the package every time you boot another kernel?

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< Daenyth> and he works prolifically
4 8 15 16 23 42

ngoonee

Forum Fellow

From: Between Thailand and Singapore

Registered: 2009-03-17

Posts: 7,356

Re: Using the same system for lowlatency pro-audio and "normal" stuff?

No, you rebuild everytime your kernels change. I have -ice (rt patch included) and stock Arch, I can boot into any one of them no problem. If the nvidia drivers get updated and I want to update, I'll just makepkg -i twice for each kernel. If stock Arch updates, I just makepkg -i once for the stock Arch nvidia PKGBUILD. Stuff like that.

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Allan-Volunteer on the (topic being discussed) mailn lists. You never get the people who matters attention on the forums.
jasonwryan-Installing Arch is a measure of your literacy. Maintaining Arch is a measure of your diligence. Contributing to Arch is a measure of your competence.
Griemak-Bleeding edge, not bleeding flat. Edge denotes falls will occur from time to time. Bring your own parachute.

thisoldman

Member

From: Pittsburgh

Registered: 2009-04-25

Posts: 1,172

Re: Using the same system for lowlatency pro-audio and "normal" stuff?

It sounds like you're on the path.  Watch out for gear lust -- "I've got to get that microphone." Or a new mixer or mike preamp or an effects box or sound barrier...