frequency scaling?

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stefabarta
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Hi everybody, i just installed Ardour 3.5.308, and during installation i got the following message:
"!!! WARNING !!! - Your system seems to use frequency scaling.
This can have a serious impact on audio latency.
For best results turn it off, e.g. by chosing the 'performance' governor."
what is frequency scaling and what should i do? i do not know what the performance governor is. thanks

veda_sticks
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Joined: 2011-03-11
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the governer is like a set of rules that controls how fast your processor works depending on what is going on. Itz meant to save power so your not running at full power when your just doing small tasks.

This can cause problems in audio programs that require quick responses, it can cause unexpected xruns, and i have also discovered that can also have an impact on gui response. in ondemand mode on my machine the gui response can get sluggish. In perofrmance its perfect. (it also effects scrollings speed in firefox on certain pages)

you can change it with

sudo cpufreq-set -c 0 -g performance

you will need to have the tools installed. Also you need to set it for each core you have, so a dual core machine you would do that and change c to 1 for the 2nd core and so on.

and eaiser way it to install the cpufreq applet that allows you to select the governer.

sudo apt-get install indicator-cpufreq

You will get a little applet on the taskbar that will lists the modes, select performance.

Now you will be running at full speed all the time.

When running in performance, you wil get less xruns and should be able to run at lower latencies, or be able to run more plugins. Just remember that if your running a larger project as you start using more plugins you may have to increase the latency if you start running into problems with x runs, or bounce tracks down to lighten to load.

http://itsfoss.com/install-cpufreq-ubuntu-1304/

stefabarta
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wow, thanks for the in depth explanation. i'll certainly try to install the applet. so is it fine to select performance mode while using ardour, and powersave when not?

veda_sticks
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yes its perfectly fine to change the governer to suit your needs.

stefabarta
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i installed cpufreq, restarted the pc, in the ubuntu software manager it shows that cpufreq is in fact installed, but i cannot find a way to start it, if i search for this app no result is showed. why could that be? thx

veda_sticks
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its not an app, there should be an applet on your taskbar. Look at the page i linked, it shows a screenshot of where you can change the cpu governer

veda_sticks
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o install cpufreq in Ubuntu 13.04 use the following command in terminal (Ctrl+Alt+T):

sudo apt-get install indicator-cpufreq

Voila! Nothing else needed here. Now just search for cpufreq in Unity Dash and it will be started. Once started, choose Powersave option to get better battery life and less overheating.

stefabarta
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thanks, it worked fine