• trivial_wannabe@lemmy.world
    32·
    11 months ago

    I looked into this a bit more and here is the summary: This is meant to show off a candidate kernel feature that allows for running different schedulers in userland.

    Task scheduling has become much more complex as CPUs have grown in size and have had new developments in architecture, so the need to develop more complex and robust schedulers is steadily rising.

    The kernel feature is meant to lower the barrier of entry for anyone who wants to try getting into schedulers, as well as enable quicker development iteration, by removing the need to completely recompile the linux kernel every time you want to test your code.

    Read more at the main project’s github: https://github.com/sched-ext/scx

    • Jordan_U@lemmy.ml
      5·
      11 months ago

      Not quite running in userspace. To the best of my own understanding:

      The new kernel feature is to allow writing schedulers in eBPF, a “language” the kernel runs in kernelspace that is heavily restricted.

      For example, all eBPF programs must complete in bounded time, and the kernel’s static checker must be able to verify that before the program can even begin executing. eBPF is a rare language that is not touring complete.

      “For scx_simple, suspending the scheduler process doesn’t affect scheduling behavior because all that the userspace component does is print statistics. This doesn’t hold for all schedulers.”

      So, it may be that eBPF also makes it easier to write a truly userspace scheduler, but that’s not the primary purpose, and it’s not what is being done with scx_simple.

      https://lwn.net/Articles/909095/ for more about (e)BPF.

  • simple@lemm.eeEnglish
    27·
    11 months ago

    Wow, that’s a huge difference. I wonder if it’s just a niche case that fixes Terraria specifically, it would be nice to see more benchmarks on other games.

    • conciselyverbose@kbin.social
      17·
      11 months ago

      I didn’t watch it all. (OK, didn’t realize it was only a minute. I basically saw everything).

      But I wonder if it’s simpler than that, and it’s just doing a better job prioritizing the game. Presumably there’s a reason they’re doing it while running a heavy background process.

      This obviously still has value if it’s the case, and is a big part of the point of a scheduler, but the headline implied (to me) that it’s a general performance improvement, and the video doesn’t demonstrate that.

  • jonne@infosec.pub
    22·
    11 months ago

    If this is in user space, does this mean we can switch schedulers on the fly? Put it in game mode when gaming, power saving mode when on battery, etc?

  • pastermil@sh.itjust.works
    8·
    11 months ago

    Now if only gccrs would mature soon!

    LLVM-based is fine for most case, but I bet a lot of people would want to stick with gcc for compiling the kernel.