Real-Time Kernel - how useful for the typical user?

[Clarity]

This is merely an informational thread that, I am sure, will be commented.

I have had direct/indirect exposure to Real-Time systems for over 4 decades: They are specialized.

Today when asked "what are the drawbacks of a realtime kernel", Duck duck go shares

Use heavy system resources: – RTOS used lot of system resources which is not as good and is also expensive. Low multi-tasking: – Multi tasking is done few of times and this is the main disadvantage of RTOS because these system runs few tasks and stay focused on them...

This is consistent with my experiences with RTOS over the years.

Linux has been used and expanded over the 3 decades so that when needed, a kernel could be yielded that would satisfy a real-time requirement for specialized uses. Hence, its use in the recent Mars mission of US and China.

In recent times I am noticing an interest for this in the forum, yet it is not mentioned "why" it is brought up. My intuitions suggest that just maybe there is a "feeling" that somehow it will improve the behavior of a generalized user experience. Even as these are produced, I have seen NO mention of performance comparative analysis of improved behavior on a PUPPY system designed for general use benefiting from a specialized real-time kernel. Again, I continue to mention "general" use benefit.

I am knowledgeable enough to know that there can be a benefit for a RTOS system put together for, say, audio OR video communications ONLY. Same is true for a system designed for musicians either individually, group, or concert symphony. Same for satellite analysis. Same for machine or lab test use. same for any specialized stand-alone use for monitoring, etc. Most of these would be example of having a need for building a distro with a specific set of specialized tasks, only.

So, please enlighten me if there is something NEW in kernel updates in why we would want a real-time kernel in a general use Puppy. Please.

Again this is merely seeking knowledge and is NOT asking for any directional changes at all.

Edited: to add a single word for clarity in 6th paragraph.

[rockedge]

the real time kernels I have created were made for specialized systems. One is to run LinuxCNC and use CAD to run CNC lathes and mills from a Puppy Linux system.
The second reason is for Puppy Linux based electronic music studio machines, and the audio/digital recording of said productions. Real time is very helpful to achieve the low latency needed for good sounding and working software synthesizers.

Reason enough?

You want to run Puppy Linux as a desktop, web server or file server? Don't use a real time kernel.

[Clarity]

Correct: And alluded to in last paragraphs of the opening post.

I am hopeful everyone understands those specializations as those are dedicated, per se, to those tasks as individual systems. And Linux kernel real-time design options allow for a tailoring specialization to dedicate machine-level performance to those specials requirements.

Thanks for demostrating to members what you have produced for use, and the beneficial changes from a generalized PUP to a specialty.

[puddlemoon]

Also important to point out that, as I understand, rt patched kernels don't play nicely with nvidia drivers. It would take extra effort to make work, if at all possible. Seems like it does't get mentioned very much. (in fact I forgot to mention it in my own remaster post)

I have recently built a low-latency (preemptable) kernel for use with audio. With a little setup this type can provide as much realtime performance as most audio users will need while being much more suitable for casual use as well.
I have had a few good sessions so far and have been able to record with as low as 5ms latency and no xruns.
Once tested a little more I will upload for those interested.

[rockedge]

I have a collection of low latency PREMPT kernels I've compiled over time. Not completely full real time but for most users needing low latency they work well.

The 5 series kernels seem easier to compile as SMP PREMPT_RT than SMP PREEMPT RT with the AUFS patch.

I've experimented for 5-6 years now with Puppy Linux and real time kernels. If you want to run software synth's AND record you are better off with full real time. Do you run CNC machinery with your Puppy?? You'll need full real time.

I run a full RT 4.19.82-rt30 on a Puppy Linux Bionic64-8.0 (since 2019) that can run a LHMP, ZoneMinder (HTML, PHP, PERL, PYTHON, BASH), zmeventnotification server, object detection/recognition including real time face recognition...do license plate identification, tell me which cat ate from which bowl, play live internet radio, stream a local web camera through DARKNET-YOLO which streams live and can be captured by ZoneMinder. The system also controls the lights and heat in the house AND I can type this post.....ALL AT THE SAME TIME.... with nvidia drivers...plus the thing monitors this forum for activity and can run 3 browsers simultaneously.

Of course this isn't for everyone. Getting just one of these things to run error free for days and days is a challenge and if one has any problems of dealing with frustration...this isn't recommended.

[gruhyrose]

many help, thanks for share.