Curious to know the coolest things you achieved by configuring your kernel. I know kernel config can be boring, but I’m hoping someone will have an impressive answer.

For me I have a very lightweight kernel that runs wayland on nvidia without any issues to date.

  • As a Linux user of almost 30 years, compiling hundreds of kernels over the years has given me a great appreciation of pre-build kernels, and a profound gratitude for those who package them up into convenient distros that work out of the box and let me get on with the rest of my life.

  • Back when I was still using Gentoo, configuring your own kernel was a rite of passage. It was kind of fun to try and configure it as minimalist as possible to cut down on the kernel compile time. Also, understanding all the different options and possibilities. And thanks to use flags, you had access to all these different patch sets for the kernel, which took a lot of the pain out of trying things like experimental schedulers or filesystems.

  •  thejml   ( @thejml@lemm.ee ) 
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    163 months ago

    Years ago (2006-ish), I ran Gentoo on a 300mhz ultra low power system I used for an irc & web server. I gained LOTS of speed and lowered power draw even further while also enabling the hardware acceleration the board had for ssl encryption and video encoding. The whole thing would pull <5 watts and be super stable. It was well worth it.

    But now days a Pi zero would trounce it in both low power draw and speed with stock kernels and I don’t really care enough to try to squeeze more out.

    • Customising the kernel just means something works properly in rare hardware configurations like you described. It’s something which he who uses the general hardware (like an X86 desktop) can’t easily see or understand because the ‘stock’ kernel is already working properly.

  •  xycu   ( @xycu@programming.dev ) 
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    3 months ago

    I do it because I can… I read release notes on every update and once you’ve configured a kernel for a particular machine you really don’t need to touch the config, barring major changes like when PATA and SATA merged. Or of course if I’m adding a new piece of hardware.

    I remove everything I don’t need and compiling the kernel only takes a couple minutes. I use Gentoo and approach everything on my system the same way - remove the things I don’t need to make it as minimal as possible.

    Compiling your own kernel also makes it easier when you need to do a git bisect to determine when a bug was introduced to report it or try to fix it. I’ve also included kernel patches in my build years ago, but haven’t needed to do that in a long time.

    I used to compile a custom kernel for my phone to enable modules/drivers that weren’t included by default by the maintainer.

    It’s not about performance for me, it’s about control.

  • I don’t know if this is considered as custom kernel, but I run Guix using non-libre Linux, with Intel Wi-Fi firmware blob. Since it does not have other firmware, it is pretty light, and I’m saving around 200-300MB.

      • Compiling kernels makes no sense anymore.

        Back in the days - Linux versions 2 and below - the kernel was much less modular, and resources wasn’t as plentiful. So it often made sense to build kernels with the stuff you needed statically compiled for speed, and the rest left out fo save memory and shorten boot time. Not to mention, Lilo (the thing we used before Grub) had limitations with respect to kernel size.

        Nowadays, Grub can load a kernel of any size from anywhere on the disk. There’s plenty enough memory and CPU to leave the kernel core slightly bloated with stuff almost nobody needs with zero practical impact on boot time and memory usage, and most everything else is compiled as modules and loaded as needed - again with next to no boot time or running speed impact.

        If you custom-build a kernel today, you’ll boot a tiny bit faster and it’ll run a tiny bit faster, and you’ll have a tiny bit more free memory - all of which you will never notice. What you will notice however is that kernel updates are a PITA on a regular basis.

      • Not really. I’ve not tweaked anything related to performance - because I’m not even sure how I would go about doing that on Guix. This makes it really easy for me to switch to custom kernels, so that’s just it. Right now, I have the option between default non-free and XanMod. Someone could package Zen or TKG on Nonguix, and that would increase the kernel choices. There’s also this option to switch to an entirely different kernel architecture, like for example, Hurd, but that probably won’t work on metal.

  • I have configured custom Android kernel builds to enable more USB drivers, enable module support, and tweak various other things. For one tangible example of the result: I could plug in a USB Wi-Fi adapter and use it to simultaneously connect to another Wi-Fi network with the internal NIC while also sharing my own AP over USB. On an Android device of all things. I have also adjusted kernel builds for SBCs (like Pi clones) to get things working at all.

    I have never seen any reason to configure a custom kernel for my own desktop/laptop systems. Default builds for the distros I’ve used have been fine for me; if I’m ever dissatisfied with anything it’s the version number rather than the defconfig. The RHEL/Rocky kernel omits a few features I want (like btrfs) but I’d rather stick to other distros on personal systems than tweak a distro that isn’t even meant for tweaking.

  • The secureblue image I use disables numerous kernel modules, and enables many kernel mitigation argument.

    The performance impact is minimal, hopefully that means a more secure system? I honestly don’t know, nor do I change the default recommended by the developer.

  • Just download the devel kernel from your distro and go into make menuconfig. I am on an Intel Laptop with recent hardware. No reason to use amd, nvidia etc drivers. And there is a shitload of likely unmaintained drivers for ancient hardware.