Real time or LTS Kernel difference?

My system is more snappy with the real time Kernel installed instead of the LTS Kernels. My question is, what is the difference between the LTS Kernels and the real time ones? What are the pros and cons of each version. Thank you.

LTS = long-term-support


real time kernel = optimized for applications that need to be processed in real time

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So, basically real time Kernels are for power users?

So basically you did not read the wiki pages, nor even the summaries that the forum created :stuck_out_tongue:

No - they are foremost for specific use cases where I/O for example has to be processed with (EDITED->) as little to any delays and if so reproducible delays so one can compensate them.

To quote the quote again:

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No… real time kernel are for application that need it…
For a desktop normal usage there is no need of a real time kernel.

That’s not really true… real time kernel have delays… just that this delay shall be assured and reproductible.
That’s not the case with a Normal Kernel the delay is not assured and depend of the load of the CPU and what he is doing

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Real time kernels are for users who need to have the lowest possible latency with I/O.
Best known application for RT is real time audio recording and editing.

A power user does NOT want RT - it’s in fact slower than a normal kernel in regard to throughput.

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You might want to check out the linux-zen kernels but, really, Manjaro kernels are tuned for desktop (rather than general) performance.

Manjaro kernels give the best OOTB experience, at least it feels that way, of any canned distro I’ve used.

regards

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As a general rule, there’s always a tradeoff between “snappiness” and throughput.
The more “snappiness” you have, the less throughput you get.
Manjaro kernels offer a very good compromise between these two, so I’d just stick with the normal kernel. RT are special purpose kernels and not really meant for everyday usage.

There are many possibilities to fine-tune a kernel in either direction, but you would have to compile your own kernel.

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Forgive me I’m not that smart when it comes to Kernels. I edit videos, photos, and audio, so which Kernel would be better? I’m new to Linux so I don’t understand a lot of this stuff.

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The LTS kernel is probably best for you. It provides stability for a desktop environment. If your hardware isn’t supported by the LTS kernel, then running the latest non real time kernel will have to do (less stability, but your hardware works).

The only reason I can think of to run the RT kernel would be if you had a media PC that just streams video to your TV, granted I would first suggest running the LTS kernel but only switch to the RT kernel if you get stuttering.

In real time environments people are only every running a fix number of applications, and never deviate.

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Thank you all for the help. I’m using the 4.9 LTS Kernel

I’m curious what you mean by “snappier”? Is it something you can measure? My gut reaction as to why the machine would feel sluggish would be CPU performance or low memory. If you run htop, how much swap is being used?

Another thing you could try is running:

sudo cpupower frequency-set -g performance

That will change the cpu governor to performance (instead of powersave), does the LTS feel snappy now?

I tried setting the CPU governor to performance with the command you gave me and this error came up. What now?

I don’t see any reason to use an RT kernel in this case… as there is no real time needed… the player in all case will use buffering even the TV. the real time kernel would not give you any improvement.

I just figured out how to set my CPU governor to performance so I’ll be testing out the 4.9 LTS Kernel and see if I notice any improvements.

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You might consider an RT kernel an eligible option for you IF you are processing real-time audio/video = producing audio/video. Pls take a look at Ubuntu Studio, based on an RT Ubuntu kernel, and, also, at it’s software suites for: Audio, Graphics, Video, Photography & Publishing

Ubuntu Studio and AVLinux both use lowlatency kernel, not realtime

Don’t need RT kernel for a lot of audio work if ultra-low latency isn’t required

There are some other adjustments to standard installation that help with audio production more than use of RT kernel. realtimeconfigquickscan can check if these settings are correct

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As an alternative, you could use a kernel with MuQSS or PDS scheduler, and use their SCHED_ISO priority which is close to real-time.
Such kernels are not in the repos though.

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