linux-tkg

This repository provides scripts to automatically download, patch and compile the Linux Kernel from the official Linux git repository, with a selection of patches aiming for better desktop/gaming experience. The provided patches can be enabled/disabled by editing the customization.cfg file and/or by following the interactive install script. You can use an external config file (default is $HOME/.config/frogminer/linux-tkg.cfg, tweakable with the _EXT_CONFIG_PATH variable in customization.cfg). You can also use your own patches (more information in customization.cfg file).

Important information

• Non-pacman distros support can be considered experimental. You're invited to report issues you might encounter with it.

• If your distro isn't using systemd, please set _configfile="running-kernel" in customization.cfg or you might end up with a non-bootable kernel

• Keep in mind building recent linux kernels with GCC will require ~20-25GB of disk space. Using llvm/clang, LTO, ccache and/or enabling more drivers in the defconfig will push that requirement higher, so make sure you have enough free space on the volume you're using to build.

• In intel_pstate driver, frequency scaling aggressiveness has been changed with kernel 5.5 which results in stutters and poor performance in low/medium load scenarios (for higher power savings). As a workaround for our gaming needs, we are setting it to passive mode to make use of the acpi_cpufreq governor passthrough, keeping full support for turbo frequencies. It's combined with our aggressive ondemand governor by default for good performance on most CPUs while keeping frequency scaling for power savings. In a typical low/medium load scenario (Core i7 9700k, playing Mario Galaxy on Dolphin emulator) intel_pstate in performance mode gives a stuttery 45-50 fps experience, while passive mode + aggressive ondemand offers a locked 60 fps.

• Nvidia's proprietary drivers might need to be patched if they don't support your chosen kernel OOTB: Frogging-Family nvidia-all can do that automatically for you.

• Note regarding kernels older than 5.9 on Arch Linux: since the switch to zstd compressed initramfs by default, you will face an invalid magic at start of compress error by default. You can workaround the issue by editing /etc/mkinitcpio.conf to uncomment the COMPRESSION="lz4" (for example, since that's the best option after zstd) line and regenerating initramfs for all kernels with sudo mkinitpcio -P

Customization options

Alternative CPU schedulers

CFS is the only CPU scheduler available in the "vanilla" kernel sources ≤ 6.5. EEVDF is the only CPU scheduler available in the "vanilla" kernel sources ≥ 6.6.

Its current implementation doesn't allow for injecting additional schedulers at kernel level, and requires replacing it. Only one scheduler can be patched in at a time. However, using Sched-ext, it's possible to inject CPU schedulers at runtime. We offer support for it on ≥ 6.8 by default. Arch users get scx schedulers from the scx-scheds package or on the AUR thanks to @sirlucjan (for persistence, set scheduler in "/etc/default/scx" and enable the scx service).

Alternative schedulers are optionally available in linux-tkg at build time:

• Project C / PDS & BMQ by Alfred Chen: blog, code repository
• MuQSS by Con Kolivas : blog, code repository
• CacULE by Hamad Marri - CFS based : code repository
• Task Type (TT) by Hamad Marri - CFS based : code repository
• BORE (Burst-Oriented Response Enhancer) by Masahito Suzuki - CFS/EEVDF based : code repository
• Undead PDS : TkG's port of the pre-Project C "PDS-mq" scheduler by Alfred Chen. While PDS-mq got dropped with kernel 5.1 in favor of its BMQ evolution/rework, it wasn't on par with PDS-mq in gaming. "U" PDS still performed better in some cases than other schedulers, so it's been kept undead for a while.

These alternative schedulers may offer a better performance/latency ratio in some scenarios. The availability of each scheduler depends on the chosen Kernel version: the script will display what's available on a per-version basis.

Default tweaks

• Memory management and swapping tweaks
• Scheduling tweaks
• CFS/EEVDF tweaks
• Using the "Cake" network queue management system
• Using vm.max_map_count=16777216 by default
• Cherry-picked patches from Clear Linux's patchset

Optional tweaks

The customization.cfg file offers many toggles for extra tweaks:

• NTsync, Fsync and Futex2(deprecated) support: can improve the performance in games, needs a patched wine like wine-tkg
• Graysky's per-CPU-arch native optimizations: tunes the compiled code to to a specified CPU
• Compile with GCC or Clang with optional O2/O3 and LTO (Clang only) optimizations.
  • Warning regarding DKMS modules prior to v3.0.2 (2021-11-21) and Clang: DKMS version v3.0.1 and earlier will default to using GCC, which will fail to build modules against a Clang-built kernel. This will - for example - break Nvidia drivers. Forcing older DKMS to use Clang can be done but isn't recommended.
• Using Modprobed-db's database can reduce the compilation time and produce a smaller kernel which will only contain the modules listed in it. NOT recommended
  • Warning: make sure to read thoroughly about it first since it comes with caveats that can lead to an unbootable kernel.
• "Zenify" patchset using core blk, mm and scheduler tweaks from Zen
• ZFS FPU symbols (<5.9)
• Overrides for missing ACS capabilities
• Waydroid support
• OpenRGB support
• Provide own kernel .config file
• ...

User patches

To apply your own patch files using the provided scripts, you will need to put them in a linux<VERSION><PATCHLEVEL>-tkg-userpatches folder -- where VERSION and PATCHLEVEL are the kernel version and patch level, as specified in linux Makefile, the patch works on, e.g linux65-tkg-userpatches -- at the same level as the PKGBUILD file, with the .mypatch extension. The script will by default ask if you want to apply them, one by one. The option _user_patches should be set to true in the customization.cfg file for this to work.

Install procedure

For all the supported linux distributions, linux-tkg has to be cloned with git. Since it keeps a clone of the kernel's sources within (linux-src-git, created during the first build after a fresh clone), it is recommended to keep the cloned linux-tkg folder and simply update it with git pull, the install script does the necessary cleanup at every run.

Arch & derivatives

git clone https://github.com/Frogging-Family/linux-tkg.git
cd linux-tkg
# Optional: edit the "customization.cfg" file
makepkg -si

The script will use a slightly modified Arch config from the linux-tkg-config folder, it can be changed through the _configfile variable in customization.cfg. The options selected at build-time are installed to /usr/share/doc/$pkgbase/customization.cfg, where $pkgbase is the package name.

Note: the base-devel package group is expected to be installed, see here for more information.

DEB (Debian, Ubuntu and derivatives) and RPM (Fedora, SUSE and derivatives) based distributions

Important notes: An issue has been reported for Ubuntu where the stock kernel cannot boot properly any longer, the whereabouts are not entirely clear (only a single user reported that, see #436).

The interactive install.sh script will create, depending on the selected distro, .deb or .rpm packages, move them in the the subfolder DEBS or RPMS then prompts to install them with the distro's package manager.

git clone https://github.com/Frogging-Family/linux-tkg.git
cd linux-tkg
# Optional: edit the "customization.cfg" file
./install.sh install

Uninstalling custom kernels installed through the script has to be done manually. install.sh can can help out with some useful information:

cd path/to/linux-tkg
./install.sh uninstall-help

The script will use a slightly modified Arch config from the linux-tkg-config folder, it can be changed through the _configfile variable in customization.cfg.

Generic install

The interactive install.sh script can be used to perform a "Generic" install by choosing Generic when prompted. It git clones the kernel tree in the linux-src-git folder, patches the code and edits a .config file in it. The commands to do are the following:

git clone https://github.com/Frogging-Family/linux-tkg.git
cd linux-tkg
# Optional: edit the "customization.cfg" file
./install.sh install

The script will compile the kernel then prompt before doing the following:

sudo cp -R . /usr/src/linux-tkg-${kernel_flavor}
cd /usr/src/linux-tkg-${kernel_flavor}
sudo make modules_install
sudo make install
sudo dracut --force --hostonly --kver $_kernelname $_dracut_options
sudo grub-mkconfig -o /boot/grub/grub.cfg

Notes:

• All the needed dependencies to patch, configure, compile or install the kernel are expected to be installed by the user beforehand.
• If you only want the script to patch the sources in linux-src-git, you can use ./install.sh config
• ${kernel_flavor} is a default naming scheme but can be customized with the variable _kernel_localversion in customization.cfg.
• _dracut_options is a variable that can be changed in customization.cfg.
• _libunwind_replace is a variable that can be changed in customization.cfg for replacing libunwind with llvm-libunwind.
• The script uses Arch's .config file as a base. A custom one can be provided through _configfile in customization.cfg.
• The installed files will not be tracked by your package manager and uninstalling requires manual intervention. ./install.sh uninstall-help can help with useful information if your install procedure follows the Generic approach.

Gentoo

The interactive install.sh script supports Gentoo by following the same procedure as Generic, symlinks the sources folder in /usr/src/ to /usr/src/linux, then offers to do an emerge @module-rebuild for convenience

git clone https://github.com/Frogging-Family/linux-tkg.git
cd linux-tkg
# Optional: edit the "customization.cfg" file
./install.sh install

Note: If you're running openrc, you'll want to set _configfile="running-kernel" to use your current kernel's defconfig instead of Arch's. Else the resulting kernel won't boot.