Table of Contents

• Overview
• Kernel Variants & Schedulers
• Features
  • Performance Optimizations
  • CPU Enhancements
  • Networking
  • Filesystem & Memory
  • Additional Features
• CachyOS Repositories
  • Quick Installation
  • Manual Installation
  • CPU Compatibility Check
  • Repository Configuration
• SCX Schedulers
• Other Distributions
• Support & Community
• Contributors

Overview

CachyOS provides a collection of enhanced Linux kernels designed for improved performance across different workloads. Kernels are built from the CachyOS Linux fork (currently based on Linux 7.1), which merges topic branches on top of upstream stable releases.

Our kernels feature multiple CPU schedulers, advanced compiler optimizations, and carefully selected patches to deliver better responsiveness and throughput.

[!NOTE] All CachyOS kernels are available in multiple architecture optimizations: x86-64, x86-64-v3, x86-64-v4, and znver4.

Kernel Variants & Schedulers

Each scheduler is optimized for different use cases. We recommend testing each one to find the best fit for your specific requirements.

Available Schedulers

Specialized Variants

• linux-cachyos - Default kernel: EEVDF scheduler with Clang Thin LTO and AutoFDO
• linux-cachyos-rc - Release candidate kernel tracking the next upstream version
• linux-cachyos-hardened - Security-focused kernel with hardening patches and the BORE scheduler
• linux-cachyos-lts - Long Term Support version (currently 6.18) with EEVDF and Cachy Sauce
• linux-cachyos-rt-bore - Real-time kernel with BORE scheduler integration
• linux-cachyos-server - Server-optimized EEVDF configuration with lazy preemption
• linux-cachyos-deckify - Handheld gaming variant with BORE scheduler, Steam Deck support, and MSI Claw driver

Compiler Variants

• linux-cachyos - Default optimized build using Clang Thin LTO with AutoFDO + Propeller profile-guided optimizations
• Scheduler-specific packages (linux-cachyos-bore, linux-cachyos-bmq, linux-cachyos-eevdf, etc.) - GCC-compiled builds without LTO, focused on scheduler choice over compiler optimizations

[!TIP] For detailed explanations of each kernel variant, visit our Kernel Wiki.

Features

The CachyOS kernel fork merges topic branches into each release. The current Linux 7.1 base integrates fifteen topic branches (amd-isp4, bbr3, cachy, cgroup-vram, drm-fair, fixes, hdmi, lenovo-wmi, mglru, preempt-ipi, sched-cluster, snd-codecs, t2, vesa-dsc-bpp, and vmalloc-free) on top of upstream stable.

Performance Optimizations

• Advanced Compilation: Highly customizable PKGBUILD with support for both GCC and Clang compilers
• Link Time Optimization (LTO): Clang Thin LTO (v12) enabled by default on the main linux-cachyos package
• Distributed ThinLTO: Support for distributed Clang ThinLTO builds to speed up kernel compilation
• Profile-Guided Optimization: AutoFDO + Propeller profiling on the default kernel for optimal code generation (Learn more)
• Kernel Control Flow Integrity (kCFI): Available when using LLVM for enhanced security
• Timer Frequency Options: Configurable between 100Hz, 250Hz, 300Hz, 500Hz, 600Hz, 750Hz, and 1000Hz (default: 1000Hz)
• Architecture Optimizations: Support for x86-64-v3, x86-64-v4, and AMD Zen4 specific builds
• Compiler Optimizations: Advanced GCC flags including -fivopts and -fmodulo-sched
• PREEMPT_DYNAMIC: Runtime-selectable preemption modes (full, lazy, voluntary, none)
• vmalloc Optimizations: Bulk page freeing in vfree(), improved vrealloc() shrink/grow paths, and optimized contiguous range freeing

CPU Enhancements

• Multiple Schedulers: BORE, EEVDF, and BMQ schedulers for different workload optimization
• POC Selector v2.6.2: Piece-Of-Cake fast idle CPU selector inspired by scx_cake, reducing wakeup latency
• Cluster-Aware Scheduling: Improved load balancing for CPU clusters, including balancing between CPUs of identical capacity on hybrid architectures
• Preempt-IPI Optimizations: Lower-latency SMP/IPI paths with preemption re-enabled before TLB flushes and streamlined smp_call_function() handling
• CachyOS Sauce: Custom CONFIG_CACHY configuration with scheduler and system tweaks
• AMD P-State Enhancements: Preferred Core support and latest amd-pstate improvements from linux-next
• Real-Time Support: RT kernel builds available with BORE scheduler integration
• Low-Latency Optimizations: Patches for improved responsiveness and reduced jitter
• sched/wait LIFO accept(): Socket accept() processed in LIFO order for better cache efficiency
• Wakeup CPU Affinity: Prefer the previous CPU for task wakeups to improve cache locality

Networking

• BBR3 TCP: BBRv3 congestion control available as a separate module alongside BBRv1

Filesystem & Memory

• ZFS Support: Built-in ZFS filesystem support with pre-compiled modules
• NTFS Improvements: Upstream NTFS driver fixes for MFT mirror validation, attribute bounds checking, and logfile handling
• MGLRU Enhancements: Unified writeback reclaim statistics, simplified vmscan accounting, improved dirty writeback reactivation, and Cachy Sauce MM tuning (LRU-gen working set protection, compaction/watermark tweaks, hugepage reclaim)
• Transparent Hugepages: ADVISE mode for shmem/tmpfs transparent hugepages
• NVIDIA Integration:
  • Proprietary NVIDIA driver modules with patches
  • Open-source NVIDIA driver support
  • Ready-to-use modules in repository
• I/O Scheduler Improvements:
  • Enhanced BFQ and mq-deadline performance
  • ADIOS v3.2.0 multi-queue I/O scheduler support
• VRAM Cgroup (DMEM): Device memory controller for restricting GPU VRAM usage per cgroup, with protection limits, common-ancestor pool sharing, and Nouveau DMEM support

Additional Features

Hardware Support

• AMD ISP4: AMD ISP 4 camera driver for supported platforms
• Gaming Hardware: Steam Deck patches (Audio, HW Quirks, HID), ROG Ally support, MSI Claw HID driver (deckify), and EasySMX 05 Pro gamepad support
• Apple Hardware: T2 MacBook support with apple-bce driver in staging
• ASUS Hardware: Extended ASUS hardware compatibility patches, including ACP audio fixes for Vivobook 18 and TUF Gaming A14 (2026)
• Lenovo Hardware: WMI battery charge limiting, GPU/CPU tunable attributes, capdata debugfs, and AMD PMC suspend delay for improved sleep/resume
• HP Hardware: OMEN Slim (including 16t-an000) and OMEN MAX laptop support via hp-wmi
• Samsung Hardware: Galaxy Book 4/5 series audio fixes via MAX98390 HDA codec support
• Graphics: HDR support enabled, AMDGPU min_powercap override (amdgpu_ignore_min_pcap), and DRM fair GPU scheduling favoring interactive clients
• Display: HDMI VRR on AMD (including PCON path and freesync-on-desktop), ALLM and passive VRR connector properties, VESA DSC bits-per-pixel parsing from EDID
• Audio Codecs: AW88399 and MAX98390 HDA side codec support

System Enhancements

• Multimedia: v4l2loopback modules included by default
• Virtualization: ACS Override support for VFIO/GPU passthrough
• Upstream Integration: Cherry-picked patches from Clear Linux and linux-next

[!NOTE] For comprehensive details about each kernel variant and their specific optimizations, visit our Kernel Documentation.

CachyOS Repositories

Our repositories contain optimized Arch Linux and CachyOS packages rebuilt with performance, stability, and security enhancements.

Available Repository Tiers

Quick Installation

Automated Setup (Recommended)

Our installation script automatically detects your CPU and configures the optimal repositories:

# Download and extract the installer
curl -O https://mirror.cachyos.org/cachyos-repo.tar.xz
tar xvf cachyos-repo.tar.xz && cd cachyos-repo

# Run the automated installer
sudo ./cachyos-repo.sh

What the script does:

• Auto-detects your CPU architecture support
• Configures appropriate repository tiers
• Backs up your existing pacman.conf
• Sets up GPG keys and mirrors

For more information, visit our GitHub or join our Discord community.

Manual Installation

Step 1: Add CachyOS Signing Keys

sudo pacman-key --recv-keys F3B607488DB35A47 --keyserver keyserver.ubuntu.com
sudo pacman-key --lsign-key F3B607488DB35A47

Step 2: Install Required Packages

sudo pacman -U \
    'https://mirror.cachyos.org/repo/x86_64/cachyos/cachyos-keyring-20240331-1-any.pkg.tar.zst' \
    'https://mirror.cachyos.org/repo/x86_64/cachyos/cachyos-mirrorlist-27-1-any.pkg.tar.zst' \
    'https://mirror.cachyos.org/repo/x86_64/cachyos/cachyos-v3-mirrorlist-27-1-any.pkg.tar.zst' \
    'https://mirror.cachyos.org/repo/x86_64/cachyos/cachyos-v4-mirrorlist-27-1-any.pkg.tar.zst' \
    'https://mirror.cachyos.org/repo/x86_64/cachyos/pacman-7.1.0.r9.g54d9411-4-x86_64.pkg.tar.zst'

[!CAUTION] About CachyOS Pacman: This installs a forked version of pacman with CachyOS-specific features like INSTALLED_FROM tracking and automatic architecture detection. While this provides enhanced functionality, it may cause compatibility warnings with standard Arch Linux workflows.

Alternative: If you prefer to avoid the custom pacman, skip the cachyos repository and only use the optimized package repositories (cachyos-v3, cachyos-v4, cachyos-extra, etc.).

Rollback Instructions

If you need to revert to standard Arch repositories after using CachyOS pacman:

sudo find /var/lib/pacman/local/ -type f -name "desc" -exec sed -i '/^%INSTALLED_DB%$/,+2d' {} \;

CPU Compatibility Check

Before manually configuring repositories, verify your CPU's instruction set support.

[!NOTE] Skip this step if using the automated installation script—it handles detection automatically.

Check Your CPU Support

/lib/ld-linux-x86-64.so.2 --help | grep supported

Understanding the Output

Look for the (supported, searched) indicators:

• ✅ x86-64-v4 (supported, searched) = CPU supports v4 instruction set
• ❌ x86-64-v4 (without parentheses) = CPU does NOT support v4

Example Output for Compatible CPU:

$ /lib/ld-linux-x86-64.so.2 --help | grep supported
  x86-64-v4 (supported, searched)
  x86-64-v3 (supported, searched)
  x86-64-v2 (supported, searched)

Instruction Set Requirements:

• x86-64-v4: Intel Haswell (2013+) / AMD Excavator (2015+)
• x86-64-v3: Intel Nehalem (2008+) / AMD Bulldozer (2011+)
• x86-64-v2: Intel Core 2 (2006+) / AMD K8 (2003+)

Repository Configuration

Edit your pacman configuration to add the appropriate repositories:

sudo nano /etc/pacman.conf

For x86-64 (Basic) Support:

# CachyOS repositories
[cachyos]
Include = /etc/pacman.d/cachyos-mirrorlist

For x86-64-v3 Support:

# CachyOS repositories (add in this order)
[cachyos-v3]
Include = /etc/pacman.d/cachyos-v3-mirrorlist
[cachyos-core-v3]
Include = /etc/pacman.d/cachyos-v3-mirrorlist
[cachyos-extra-v3]
Include = /etc/pacman.d/cachyos-v3-mirrorlist
[cachyos]
Include = /etc/pacman.d/cachyos-mirrorlist

For x86-64-v4 Support:

# CachyOS repositories (add in this order)
[cachyos-v4]
Include = /etc/pacman.d/cachyos-v4-mirrorlist
[cachyos-core-v4]
Include = /etc/pacman.d/cachyos-v4-mirrorlist
[cachyos-extra-v4]
Include = /etc/pacman.d/cachyos-v4-mirrorlist
[cachyos]
Include = /etc/pacman.d/cachyos-mirrorlist

For AMD Zen4 CPUs:

# CachyOS repositories (Zen4 optimized)
[cachyos-znver4]
Include = /etc/pacman.d/cachyos-v4-mirrorlist
[cachyos-core-znver4]
Include = /etc/pacman.d/cachyos-v4-mirrorlist
[cachyos-extra-znver4]
Include = /etc/pacman.d/cachyos-v4-mirrorlist
[cachyos]
Include = /etc/pacman.d/cachyos-mirrorlist

Finalize Installation:

# Update package databases and system
sudo pacman -Syu

🎉 Congratulations! Your system is now optimized with CachyOS packages.

Debug Packages

Debug symbols are available through debuginfod. Configure it by creating:

# Create debuginfod configuration
sudo mkdir -p /etc/debuginfod
echo "https://debuginfod.cachyos.org" | sudo tee /etc/debuginfod/cachyos.urls

Uninstalling CachyOS Repositories

For complete removal instructions, see our Uninstallation Guide.

SCX Schedulers

CachyOS supports the new sched-ext (SCX) framework for userspace schedulers. For setup and configuration, see our sched-ext Tutorial.

[!WARNING] SCX schedulers are not compatible with the linux-cachyos-bmq kernel variant.

Other Distributions

CachyOS kernels are available for other Linux distributions through community efforts:

Gentoo Linux

Community-maintained ebuilds for dynamic kernel building:

# Add the CachyOS kernels overlay
eselect repository add CachyOS-kernels git https://github.com/Szowisz/CachyOS-kernels
emaint sync -r CachyOS-kernels

Repository: Szowisz/CachyOS-kernels

Fedora Linux

COPR repository with multiple kernel variants:

• linux-cachyos-bore
• linux-cachyos-rt-bore
• linux-cachyos-bore-lto
• linux-cachyos-lts

Maintainer: bieszczaders
Installation: Visit the COPR page for setup instructions

NixOS

Precompiled kernels available through the xddxdd/nix-cachyos-kernel repository:

Repository: xddxdd/nix-cachyos-kernel
Setup: Follow the installation guide

Support & Community

Get Help

• Discord: CachyOS Community
• Forum: discuss.cachyos.org
• Telegram: CachyOS Group

Support Development

Help us maintain repositories and build infrastructure:

• Patreon: patreon.com/CachyOS
• BTC: bc1qmwglfchlc335du6pcu6w64cexu7cck0mzhyw42
• ETH: 0xc2dc77327F78A7B85Db3941Eb49e74F41E961649
• LTC: LgGTwcEBcXqMgNT6XyyNWABMb7dZVtVg9w

Contributors

Special thanks to our key contributors:

• firelzrd - BORE Scheduler developer
• Arch Linux - Foundation distribution
• Linux Kernel Community - Upstream kernel development
• All CachyOS contributors and community members