CachyOS COPR Repository for Fedora

Goodies from CachyOS ported to Fedora.

This repository is maintained by @andersrh and @TrixieUA.

• Kernels
  • Features
  • Installation Instructions
    • Default Kernel
• Addons
  • CachyOS-Settings
  • scx-scheds
  • scx-manager
  • ananicy-cpp

🐧 Kernels

We offer a variety of CachyOS kernels ported to Fedora:

• kernel-cachyos - 1000 Hz kernel with BORE scheduler
• kernel-cachyos-lts - LTS kernel with BORE scheduler
• kernel-cachyos-rt - Real-time kernel with BORE scheduler
• kernel-cachyos-server - 300 Hz kernel with default EEVDF scheduler

For Fedora Workstation and Silverblue we recommend kernel-cachyos and for Fedora Server, Cloud and CoreOS we recommend kernel-cachyos-server. The LTS and Real-time kernels are for special use cases (think embedded systems) and are not recommended unless your application requires them.

🌟 Features

• Choose between GCC and LLVM-ThinLTO
• Optimized for x86-64v3 CPUs for kernel-cachyos and x86-64v2 for kernel-cachyos-lts and kernel-cachyos-server
• BORE scheduler with sched-ext support (excl. kernel-cachyos-server, sched-ext support only for kernel-cachyos)
• AMD P-State Preferred Core, AMD CPB Switch and upstream amd-pstate enchancements (exclusive to kernel-cachyos)
• Cachy Sauce - Provides tweaks for the scheduler and other settings
• Prebuilt nvidia-open kernel modules
• Latest & improved ZSTD patchset
• Improved BFQ Scheduler
• BBRv3 tcp_congestion_control
• v4l2loopback modules as default included
• Cherry picked patches from Clear Linux
• Backported patches from linux-next
• OpenRGB and ACS Override support
• NTSync patched and integrated into the kernel (exclusive to kernel-cachyos)

⬇️ Installation Instructions

Make sure your CPU supports the higher target x86-64 architectures. You need minimum x86-64-v3 for all kernels, except kernel-cachyos-lts and kernel-cachyos-server that only require x86-64-v2.

/lib64/ld-linux-x86-64.so.2 --help | grep "(supported, searched)"

Next, enable the COPR repository hosting the kernels.

sudo dnf copr enable bieszczaders/kernel-cachyos # For GCC built kernels
# or
sudo dnf copr enable bieszczaders/kernel-cachyos-lto # For LLVM-ThinLTO build kernels

Now you can install the kernels

sudo dnf install kernel-cachyos kernel-cachyos-devel-matched # For GCC built kernels
# or
sudo dnf install kernel-cachyos-lto kernel-cachyos-lto-devel-matched # For LLVM-ThinLTO built kernels

## LTS Kernel
sudo dnf install kernel-cachyos-lts kernel-cachyos-lts-devel-matched
# or
sudo dnf install kernel-cachyos-lts-lto kernel-cachyos-lts-lto-devel-matched

## Real-time Kernel
sudo dnf install kernel-cachyos-rt kernel-cachyos-rt-devel-matched

## Server Kernel
sudo dnf install kernel-cachyos-server kernel-cachyos-server-devel-matched

🚨 Lastly if you use SELinux, you need to enable the necessary policy to be able to load kernel modules.

sudo setsebool -P domain_kernel_load_modules on

Fedora Silverblue

cd /etc/yum.repos.d/
sudo wget https://copr.fedorainfracloud.org/coprs/bieszczaders/kernel-cachyos/repo/fedora-$(rpm -E %fedora)/bieszczaders-kernel-cachyos-fedora-$(rpm -E %fedora).repo
sudo rpm-ostree override remove kernel kernel-core kernel-modules kernel-modules-core kernel-modules-extra --install kernel-cachyos
sudo systemctl reboot

Default Kernel

By default Fedora will use the kernel that was most recently updated by dnf which will lead to inconsistent behaviour if you have multiple kernels installed, but we can tell Fedora to always boot with the latest CachyOS kernel by running a script after kernel updates.

Create a file in /etc/kernel/postinst.d:

sudo nano /etc/kernel/postinst.d/99-default

Enter the following content that will set the latest CachyOS kernel as the default kernel:

#!/bin/sh

set -e

grubby --set-default=/boot/$(ls /boot | grep vmlinuz.*cachy | sort -V | tail -1)

Make root the owner and make the script executable:

sudo chown root:root /etc/kernel/postinst.d/99-default ; sudo chmod u+rx /etc/kernel/postinst.d/99-default

The next time any installed kernel (e.g. the official Fedora kernel) gets an update, the system will change default kernel back to the latest CachyOS kernel. This way you can keep the official kernel as a backup in case an update goes wrong and you need to temporarily switch to the official kernel.

🧩 Addons

We provide a few addons that supplement the kernel packages and system.

• CachyOS-Settings - Settings used in CachyOS (includes modprobe config, udev rules, etc) packaged for Fedora.
• scx-scheds - sched-ext schedulers. Provides both scx-scheds releases and scx-scheds-git package.
• scx-manager - Simple GUI for managing sched-ext schedulers via scx_loader.
• ananicy-cpp & cachyos-ananicy-rules - Auto nice daemon with rules support.

⬇️ Installation instructions

First, enable the COPR repository hosting addon packages.

sudo dnf copr enable bieszczaders/kernel-cachyos-addons

Now you can install the addon packages.

CachyOS-Settings

sudo dnf install cachyos-settings
sudo dracut -f

scx-scheds

sudo dnf install scx-scheds
#or
sudo dnf install scx-scheds-git # For -git package

# Choose which scx scheduler to use by editting `/etc/default/scx`
sudo nano /etc/default/scx

# Then enable the systemd service to make it persistent across boots
sudo systemctl enable --now scx.service

Along with the release of scx-scheds 1.0.11 (this is already possible in scx-scheds-git), it will be available to use scxctl to start/change the scheduler with profiles/custom flags.

scx-manager

sudo dnf install scx-manager

ananicy-cpp

It is advised against running ananicy-cpp and a scheduler from the sched-ext framework simultaneously. Use one but not the other.

sudo dnf install ananicy-cpp
sudo systemctl enable --now ananicy-cpp