- cross-posted to:
- linux@lemmy.ml
- cross-posted to:
- linux@lemmy.ml
To get started with the real-time kernel for Ubuntu 24.04, check out the official documentation. One thing to keep in mind if you’re an NVIDIA GPU user is that the real-time Ubuntu kernel does not support the proprietary NVIDIA graphics drivers.
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Why are we monetizing a kernel flag?
Can somebody explain real time kernel as if I am a golden retriever ?
Who a good boy? You a good boy!
Music recording? Idk
Yeah that’s exactly one of the niche use cases, like using a midi keyboard, though using a low latency kernel like Linux Zen would be more than enough for most users.
An alternative definition: a real-time system is a system where the correctness of the computation depends on a deadline. For example, if I have a drone checking “with my current location + velocity will I crash into the wall in 5 seconds?”, the answer will be worthless if the system responds 10 seconds later.
A real-time kernel is an operating system that makes it easier to build such systems. The main difference is that they offer lower latency than a usual OS for your one critical program. The OS will try to give that program as much priority as it wants (to the detriment of everything else) and immediately handle all signals ASAP (instead of coalescing/combining them to reduce overhead)
Linux has real-time priority scheduling as an optional feature. Lowering latency does not always result in reduced overhead or higher throughout. This allows system builders to design RT systems (such as audio processing systems, robots, drones, etc) to utilize these features without annoying the hell out of everyone else.
So, contrary to what it seems a single CPU core can only execute a single “thing” at a time. Modern operating systems do something called “preemptive multitasking” to give the illusion that more than one things are running at a time. The OS will start your task, then after a while save its state and start another task running, then switch back. It does this fast enough that each job seems to be running concurrently.
Now if you’re running on a RaspberryPI your program might be waiting for input from a GPIO pin. And when you get that input you want to turn on some switch. Maybe an important switch. BUT It could be that your application is in the “paused” state when that pin gets input which will cause a delay between when the pin is trying to send you input and when you actually process it.
A real-time OS minimizes such delays (latency) so that you can respond quickly.
I guess i am still skipping on how real time kernel address the pause? it just never pauses or it no longer needs to be paused?
as a side note, is this similar technology they use in high precision manufacturing?
Think of it like a club with a max capacity of 10 people, where some people have VIP cards. If a person with a VIP card wants to get into the club, the bouncer will kick out one of the people inside that doesn’t have a VIP card to make space for them.
For a more technical explanation:
There are several processors on computers and each can be in use by 1 process at a time. Different processes can get different amounts of time based on their priority (called niceness in Linux) and they’ll be removed from the processor once their time is up until their next share of time.
On a real-time kernel some processes are marked as real-time (certain range of niceness values, can’t remember the exact range). If a process that is real-time says it needs some processor time, a process that isn’t real-time that’s currently running will be immediately ripped off the processor to make room for the real-time process.
Alright, this landed!
You can just enable all of these features on any 6.8+ kernel. You don’t need Ubuntu Pro.
No, it will no radically improve your gaming performance, but it will definitely increase your energy bill.
Why would it increase your energy bill?
I guess, the governor is set to performance for a realtime kernel to work properly, thus the CPU consumes more power.
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