Processor frequency setting - Jack CPU use

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Blindekinder
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Posts: 55
Joined: Sat Jan 26, 2013 11:42 pm

Processor frequency setting - Jack CPU use

Post by Blindekinder »

Hi,
just as tip:
On my fresh KX 14.04 instlall on my new laptop, I had an abnormally high CPU use in Jack, like 3%-4% @ ~20ms with no sound-app. I changed CPU freq mode in applet (right bottom taskbar, don't remember if it was installed by default) to "Performances", and I turned back to moderate value, < 1%.
KX on (K)Ubuntu 14.04 - RME Multiface - Jack2

bazsound
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Posts: 480
Joined: Sat Aug 03, 2013 11:46 am

Re: Processor frequency setting - Jack CPU use

Post by bazsound »

the Performance governer is recomended to be used when working with audio as cpu frequency scaling cause cause problems.

when your not working with audio, you can switch back to 1 of the more power efficient governers to save battery.

Blindekinder
Established Member
Posts: 55
Joined: Sat Jan 26, 2013 11:42 pm

Re: Processor frequency setting - Jack CPU use

Post by Blindekinder »

yes, besides the high cpu usage, I had some xruns...
Strange thing is that it was on Eco (or other, I don't remember for sure) by default!
KX on (K)Ubuntu 14.04 - RME Multiface - Jack2

Alwaysanewb
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Posts: 232
Joined: Sat Oct 13, 2012 9:04 pm

Re: Processor frequency setting - Jack CPU use

Post by Alwaysanewb »

Are you guys controlling cpu mode from the terminal or what programs are you using?

Blindekinder
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Posts: 55
Joined: Sat Jan 26, 2013 11:42 pm

Re: Processor frequency setting - Jack CPU use

Post by Blindekinder »

I installed some applets, and don't remember if it was installed by default. Was it?
KX on (K)Ubuntu 14.04 - RME Multiface - Jack2

Thad E Ginathom
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Posts: 369
Joined: Fri Sep 23, 2011 1:03 pm

Re: Processor frequency setting - Jack CPU use

Post by Thad E Ginathom »

I am currently only listening to music, so not putting much strain on the system, but I find that the key is to fix the cpu speed. It doesn't have to be at the highest but it has to be fixed.

Without that, I get drop-outs. It is the same whether I am using a media player with Calf plugins and Jack, or a simple media-player-->ALSA setup.

I have no idea what is going on, except that it is something to do with memory management and CPU throttling, but my hunch is that it is changing the CPU frequency that disturbs the audio.

And I use the same CPUfreq indicator to control this.

bazsound
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Posts: 480
Joined: Sat Aug 03, 2013 11:46 am

Re: Processor frequency setting - Jack CPU use

Post by bazsound »

Yes that is correct,

its the switcxhing frequencies that causes problems, if you stay at a set frequency it should be fine.

I use performance when working with audio as i usually end up pushing the dsp to the limits on my machine.

If you install the applet and it doesnt show up on your taskbar, you may have an option disabled in your bios which should mean that you will be running at full clock.

In my desktop theres an option to turn on and off the cpu scaling.

ssj71
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Posts: 1293
Joined: Tue Sep 25, 2012 6:36 pm

Re: Processor frequency setting - Jack CPU use

Post by ssj71 »

I use qjackctl, but I wrote a couple little scripts that set the governor to performance when jack starts and back to ondemand when it stops. Qjackctl is configured to run these automatically. So I never worry about what the governor is set to anymore.
_ssj71

music: https://soundcloud.com/ssj71
My plugins are Infamous! http://ssj71.github.io/infamousPlugins
I just want to get back to making music!

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