[LAD] Jackd & Real Time Kernel

[Tim]

On 01/13/2018 09:58 AM, Benny Alexandar wrote:
> Hi Len,
> 
> I'm using� jackdmp 1.9.12.� I checked the file 
> /etc/security/limits.d/audio.conf, and is
> named as audio.conf.disabled. How to enable this ?


Try installing a package, I think it's called ubuntu studio controls.
It adds a start menu item for one-click easy setup of several
  real time audio settings like this one. No file editing required.

Also you might want to actually install package ubuntu studio.
It installs several audio related packages for audio production.
It saves you the task of manually installing them all.

Tim.

> 
> When I run my jack client standalone program, I could see the prints as 
> follows,
> 
> ------------------
> jackdmp 1.9.12
> 
> JACK server starting in realtime mode with priority 10
> self-connect-mode is "Don't restrict self connect requests"
> Cannot lock down 82280346 byte memory area (Cannot allocate memory)
> creating alsa driver ... hw:0|hw:0|1024|2|48000|0|0|nomon|swmeter|-|32bit
> configuring for 48000Hz, period = 1024 frames (21.3 ms), buffer = 2 periods
> ALSA: final selected sample format for capture: 32bit integer little-endian
> ALSA: use 2 periods for capture
> ALSA: final selected sample format for playback: 32bit integer little-endian
> ALSA: use 2 periods for playback
> Cannot use real-time scheduling (RR/10)(1: Operation not permitted)
> AcquireSelfRealTime error
> Cannot lock down 82280346 byte memory area (Cannot allocate memory)
> JACK server started
> Cannot use real-time scheduling (RR/5)(1: Operation not permitted)
> JackClient::AcquireSelfRealTime error
> -----------------------------------
> 
> -ben
> 
> 
> 
> ------------------------------------------------------------------------
> *From:* Len Ovens <len at ovenwerks.net>
> *Sent:* Friday, January 12, 2018 10:27 PM
> *To:* Benny Alexandar
> *Cc:* linux-audio-dev at lists.linuxaudio.org
> *Subject:* Re: [LAD] Jackd & Real Time Kernel
> On Fri, 12 Jan 2018, Benny Alexandar wrote:
> 
>> I just compiled simple_client.c and things starts to work.
>> My doubt is do I need to install linux real-time kerel update for JACK.
> 
> It depends... personally, I use the lowlatency kernel with no problems
> using an ice1712 based PCI card audio interface. Your situation may
> differ.
> 
>> How do I know if jack is running real time, is it by checking for xruns ?
> 
> Jack runs in real time mode by default. If you are running jackd2 (version
> 1.9*) then check ~/.log/jack/jackdbus.log
> 
> for the line:
> Thu Dec 28 10:38:26 2017: JACK server starting in realtime mode with
> priority 10
> 
> Otherwise the same line will appear in jackd terminal output when started.
> 
> Do note that part of the jackd instalation process sometimes gets missed
> by some installers. There should be a file
> /etc/security/limits.d/audio.conf If this is missing or named as disabled,
> you may not be able to get jackd to start in realtime mode. The two lines
> of importance in that file are:
> @audio�� -� rtprio���� 95
> @audio�� -� memlock��� unlimited
>  � Depending on your distro the group may be other than audio. Whatever 
> that
> group is, your user needs to be a part of it. Most audio distributions get
> this right already (even ubuntustudio), but non-audio distros generally
> need this to be fixed. After adding yourself to the audio (or whatever)
> group you will need to logout and back in before that will have any
> effect.
> 
> --
> Len Ovens
> www.ovenwerks.net <http://www.ovenwerks.net>
> 
> 
> 
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