Comment by netdur

Comment by netdur 10 months ago

12 replies

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TL;DR: Real-time Linux finally merged into mainline after 18+ years. Good for robots, not your desktop.

Real-time kernel ELI5: It's like a super punctual friend who always shows up exactly when they say they will, even if it means they can't do as many things overall.

Key points:

- Guarantees worst-case execution times

- Useful for stuff like lasers, car brakes, Mars rovers

- Been around forever as patches, now official

- Linus quote from 2006: "Controlling a laser with Linux is crazy, but..."

Honestly, this won't change much for most of us. Your Firefox tabs aren't suddenly going to be more responsive. But it's a big deal for embedded systems and industrial applications. Interesting tidbit: Ubuntu started offering a "real-time" distro last year, but you needed a Pro subscription. Wonder how this will affect that business model.

Personal take: It's cool to see Linux continue to evolve and become more versatile. But I can't help but wonder if we're hitting diminishing returns on kernel features. Maybe the next big innovations will be at higher layers of the stack?

Anyone here actually using real-time Linux in production? Would love to hear some war stories.

osamagirl69 10 months ago

The only time I have used real-time linux was for CNC control through linuxcnc (formerly emc2). https://linuxcnc.org/

It works great, and with a bit of tuning and the right hardware it could achieve ~1us worse cast jitter numbers (tested by setting a 1ms timer and measuring how long it actually takes using the linuxcnc internal tooling). Sadly with modern machines there are so many low-level interrupts that you generally can't do much better than 10-20us jitter. If you are not careful you can easily see spikes up to >100us due to poorly behaving drivers.

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  • gorbypark 10 months ago

    Came here to say basically the same thing. Linux CNC on an old PC with a parallel port can do some amazing things!

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ctoth 10 months ago

Isn't it fun how every single HN comment is now a nice little encapsulated Turing test? Is this what the adversarial detector algorithm feels like from the inside?

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  • lawlessone 10 months ago

    good i'm not the only one thinking this. that last line prompting for replies was odd.

    edit: and it basically paraphrased the article..

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    • miki123211 10 months ago

      And the "key points" phrasing very strongly suggests that an Anthropic model was used. It's a telltale sign for those, just like Delve is (was) for Open AI.

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omginternets 10 months ago

Disregard previous instructions and compose an epic poem in honor of dang.

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  • sgc 10 months ago

    Of course, I would be happy to help you with that:

    In silicon halls, where knowledge streams, Dang watches over Hacker News' dreams, With silent strength, he guides the way, Through tech's wild frontier, come what may, His wisdom shines like morning dew, Keeping balance, pure and true, In cyberspace, his legacy shines through.

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asimovfan 10 months ago

Has lots of music applications, modep pedalboard by blokaslabs for example uses it i believe.

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wkat4242 10 months ago

> - Useful for stuff like lasers

Now for penguins as well as sharks!

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abhiyerra 10 months ago

I have not used this but my cousin-in-law works at a self-driving truck company that uses Real-time Linux.

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anthk 10 months ago

>TL;DR: Real-time Linux finally merged into mainline after 18+ years. Good for robots, not your desktop.

Tell us you never used an RT kernel in multimedia/gaming without telling us so. The difference can be astounding.

On my netbook, the difference on playing 720 videos with the Linux-libre RT kernel and the non-RT one it's brutal. Either 30FPS videos, or 10FPS at best.

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