Low latency kernel in Ubuntu studio vs Linux Mint

I am wondering how much difference the low latency kernel does for Ardour?

The background: I successfully installed Ubuntu studio with Ardour on an old Macbook pro as a test case. After that i planned to also install it on my main computer in the studio. So far I have just tried to run it from an USB stick but ran into problems… the Studio-controls app wont run at all and dies silently after a few seconds. So my thought is to try Linux Mint on that computer as I run it on a few other computers and have a lot of faith in it. But my worries are that the audio setup will be much more difficult and that I will miss the low latency kernel, but I have no idea how big an issue that is. I hope someone with that experience can enlighten me on how important that is for Ardour?

Computer spec:
ASUS ROG Strix B450-F GAMING, Socket-AM4
AMD Ryzen 9 3900 Prosessor Tray
Gainward GeForce RTX 2070 SUPER Phoenix GS
HyperX Fury DDR4 3200MHz 16GB
HyperX Fury DDR4 3200MHz 16GB
WD Black SN750 1TB M.2 SSD
Intel 660p 2TB M.2 SSD
Corsair TX650M, 650W PSU

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I run Linux Mint Cinnamon for years now as everyday system and also for maybe three years now as my main audio system - and about one year ago I even ditched my decades-old dual boot approach and do everything in my one and only system now!

After trying several older versions of AVLinux and other media distros, I came back to Mint’s comfort (I am used to it of course)… In Mint I tried several special kernels (and ran into more problems than benefits), but I came to the conclusion that this is of no more concern to me. I tweaked a couple of things in Mint (CPU governor etc. - basically the main things that realtimeconfigquickscan suggests) and am very happy with the standard kernel (currently 5.15.0-58-generic), run very low latencies (RME Fireface UFX II) and have no dropouts or problems whatsoever…! So I don’t care about all that any longer.

(I followed the suggestion to use “threadirqs kernel option”, see here: System configuration [Linux-Sound])

The newer versions of AVLinux look very nice and of course AVLinux has a great lot to offer for sure - but I simply don’t need 80% of all that (doing mainly “old-school” recording and mixing work with real instruments and real musicians :sweat_smile:). I really only need Ardour and my set of quality plugins. And for that I don’t mind setting things up manually.

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I use Linux Mint with the low latency kernel installed via the Ubuntu Studio Installer. My hardware is a decade old but it works very well and does everything I need (and more).

I think the performance is a bit better than the vanilla kernel but honestly I’m not too sure, it could just be in my head.

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Thank you for your reply. That sounds great for what I am aiming at! Do you mind naming the quality plugins you use? Are they FOSS or commercial ones?

I tried out Mint 21, Ubuntu Studio an AV Linux.
I use Mint 21.1 cinnamon. All others are for me to spartanical in using. I don’t have any performance advantage with the other tested. (except you find mor plugins pre installed).

For performance in my experience is the most important thing, to switch the governor to performance mode. Low latency kernel is not a theme if you have some midi instruments in your ardour project.

The latency depends of your DSP value.

Here I made a thread with some installation tutorials.

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Thank you , Stefan! Your installation tutorial look very interesting. Do you not use the studio-controls app or Cadence or something like that?

I know you’re not asking me this but because my use case is similar to laex’s (i.e. mostly audio recording and mixing etc) I thought I’d chime in anyway.

On my machine there are lots and lots of plugs installed, mostly FOSS from the audio plugins package from Ubuntu Studio. However I only really use some Airwindows plugins and the glorious Applied Computer Music Technologies Ltd linux plugin set (www.acmt.co.uk - these are commercial but they’re honestly outstanding and are worth 10x the price I think).

A couple GVST plugins are good too (free as in beer) and the Zam ones, especially the dynamic EQ.

No, i use only Ardodur in ALSA and the Plugins in my tutorial.

Just the usual suspects, I guess: mainly Harrison, x42, Zam, LSP…

Ubuntu and Mint are (almost) the same thing. The base system is exactly the same (it even uses directly the package repositories of Ubuntu). So, the available Kernels are exactly the same (not necessarily the one installed by default), and also the same are the audio subsystems, etc.

To get the same optimizations which are present by default in Ubuntu Studio, just install the package “ubuntustudio-performance-tweaks” and an “RT” version of the Kernel. That’s all.

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Thanks for clarifying :raised_hands:

Thank you? How do I install the RT kernel?

In a terminal, type apt-cache search linux-image rt, then install one of those, for example the same version you have at the moment.

To now which kernel you are currently running, type uname -a.

(If the terminal makes you nervous you can probably also use some kind of graphic interface, e.g. synaptic, and do the search / install there.)

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You should be able to do that from Mint “Software Manager” (mintinstall) or -as @Piergi correctly said- from another package manager such as synaptic (GUI) or apt (command line).

Same goes for “ubuntustudio-performance-tweaks”.

P.S.: the names of the “RT” kernel meta-package in the current version of Linux Mint (21.x = Ubuntu 22.04) is “linux-lowlatency”. Installing that will install the latest version of the rt kernel and will keep it up-to-date.

From the command line:

sudo apt install linux-lowlatency

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Is linux-lowlatency the same as RT? There is a kernel build option called PREEMPT which gets most of the benefits of latency reduction patches, but does not utilize the full RT patch. The full patch results in an additional build option called PREEMPT_RT. Some distributions ship a kernel marked as low latency with PREEMPT defined, but without the full PREEMPT_RT patch. If those distributions have a full RT kernel it would typically include RT or rt in the name.
The page I could find with Ubuntu kernel versions was not explicit which build options were used for the linux-lowlatency build.

Don’t know. Personally I’m fine with the default Kernel, I do not even use the -lowlatency variant. AFAIK, nowadays all current (Ubuntu and direct derivatives) Kernels includes by default some -limited- RT features:

# CONFIG_RT_GROUP_SCHED is not set
CONFIG_SCHED_HRTICK=y
CONFIG_RT_MUTEXES=y
# CONFIG_PREEMPT_NONE is not set
CONFIG_PREEMPT_VOLUNTARY=y
# CONFIG_PREEMPT is not set
CONFIG_HAVE_PREEMPT_DYNAMIC=y
CONFIG_PREEMPT_NOTIFIERS=y
CONFIG_DRM_I915_PREEMPT_TIMEOUT=640
# CONFIG_PREEMPTIRQ_DELAY_TEST is not set

Low-latency variants should include some more. For sure, those are the kernels used by “Ubuntu Studio” variant.