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CachyOS Kernels

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tagsnote/cachyos

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Part of CachyOS Wiki Notes. From the official CachyOS wiki (last updated 2026-08-31).

CachyOS Kernels

A customized kernel: upstream enhancements, configs and patches.

Performance characteristics

  • Customizable PKGBUILD (GCC or Clang); Clang Thin LTO by default on linux-cachyos; distributed ThinLTO builds; AutoFDO profiling on the default kernel; kCFI with LLVM.
  • Timer frequency options 100/250/300/500/600/750/1000 Hz (default 1000 Hz); x86-64-v3, x86-64-v4 and AMD Zen4 builds; -fivopts / -fmodulo-sched; PREEMPT_DYNAMIC.
  • CPU/sched: BORE, EEVDF, BMQ schedulers; POC Selector (scx_cake-inspired fast idle CPU selector); CONFIG_CACHY (“CachyOS Sauce”); AMD P-State preferred-core + linux-next amd-pstate; RT builds with BORE; sched/wait LIFO accept().
  • Networking: BBRv3 TCP available as a separate module alongside BBRv1.
  • FS/memory: built-in ZFS with precompiled modules; NTFS fixes; MGLRU/MM tuning; NVIDIA proprietary (patched) + open modules ready in-repo; BFQ and mq-deadline improvements; ADIOS 3.2.0 multi-queue I/O scheduler; VRAM cgroup (DMEM).
  • Hardware: AMD ISP4 camera; Steam Deck / ROG Ally / MSI Claw (deckify) HID; T2 MacBook apple-bce in staging; ASUS patches; Lenovo WMI battery charge limiting; HP OMEN Slim/MAX via hp-wmi; HDR enabled; amdgpu_ignore_min_pcap; HDMI VRR on AMD, ALLM, passive VRR, VESA DSC from EDID; AW88399 and MAX98390 HDA side codecs.
  • Other: v4l2loopback by default; ACS Override for VFIO/GPU passthrough; Clear Linux and linux-next cherry-picks; unstripped dbg variant (needed for AutoFDO); Binder module enabled (Waydroid).

Variants

All ship the CachyOS Base Patchset. Each has a corresponding -lto variant built with Clang instead of GCC.

VariantNotes
linux-cachyosDefault, recommended. 1000Hz, Clang + ThinLTO, AutoFDO profiled
linux-cachyos-boreBORE scheduler
linux-cachyos-bmqBMQ scheduler from Project C (Alfred Chen). No sched-ext support
linux-cachyos-deckifyDefault for handhelds; BORE + handheld patches. Other kernels are not recommended/unsupported on handhelds
linux-cachyos-eevdfTweaks the default scheduler for responsiveness
linux-cachyos-ltsLatest LTS, BORE, minimally patched for stability
linux-cachyos-hardenedBORE + linux-hardened patchset and config; aggressive hardening that stifles performance. No sched-ext support
linux-cachyos-rcLatest mainline (Linus’s tree); where new patchset features land first
linux-cachyos-serverServer workloads: 300Hz tickrate, no preemption, stock EEVDF
linux-cachyos-rt-boreReal-time preemption, BORE scheduler

Package naming convention

linux-cachyos                                    # default, Clang + ThinLTO
linux-cachyos-hardened                           # GCC-built
linux-cachyos-hardened-lto                       # clang-compiled counterpart
linux-cachyos-hardened-{,lto-}headers
linux-cachyos-hardened-{,lto-}nvidia
linux-cachyos-hardened-{,lto-}nvidia-open
linux-cachyos-hardened-{,lto-}zfs
linux-cachyos-hardened-{,lto-}dbg

Prebuilt modules

ZFS and NVIDIA modules ship precompiled, so there is no rebuild per kernel update and -dkms equivalents are obsolete. Both NVIDIA closed and open modules are precompiled and patched with community/NVIDIA patches to stay compatible with the latest kernel (out-of-tree module, off upstream cadence).

FAQ

  • AutoFDO is only on linux-cachyos because it is expensive: build with AutoFDO+debug → create a profile by running workloads → rebuild with the profile.
  • The realtime kernel does not improve gaming performance: far more code is preemptible, so gaming processes get preempted frequently and give resources back.

Related: CachyOS Kernel Manager, Optimized Repositories and x86-64 Levels, sched-ext Schedulers.

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