BobZKernel — Optimized Linux 7.2

Custom optimized Linux kernel 7.2.x with the BORE scheduler, RSEQ abort latency observability, and performance/security tuning. Primary target is the Lenovo LOQ 15IRH8 laptop; hardware-specific variants live in separate branches and ship as separate GitHub releases.

Hardware variants

Variant	Branch	Target hardware	Release
Default (laptop)	master / linux-7.2	Intel Raptor Lake (Lenovo LOQ 15IRH8, 12th-14th gen)	v7.2.2
workpc	workpc	AMD FX-series Piledriver desktop (AM3+ with Radeon HD7000-class iGPU)	v7.1.0-workpc
Pixel Slate	pixel-slate	Google Pixel Slate (codename nocturne, Skylake/Kaby Lake)	v7.1.0-pixel-slate
Generic x86-64-v2	generic-build	Universal modern x86-64 (Intel Nehalem 2008+, AMD Bulldozer 2011+)	v7.1.1-generic

Each variant uses the same core patch stack and feature set, but differs in CPU codegen target (-march=native / -march=bdver2 / -march=skylake / -march=x86-64-v2) and driver subset (Pixel Slate keeps ChromeOS EC drivers + AVS audio; workpc keeps Radeon built-in for early KMS; etc.). Pick the variant that matches your hardware.

Features

Scheduler

• BORE Scheduler — Burst-Oriented Response Enhancer for desktop responsiveness (vanilla-compatible variant; CachyOS-required version intentionally not used).
• CONFIG_RSEQ_SLICE_EXTENSION=y — RSEQ time slice extension. Graduated to mainline in Linux 7.0.
  • Runtime tunable: /sys/kernel/debug/rseq/slice_ext_nsec (range 5000–50000 ns)
  • Observability via /sys/kernel/debug/rseq/stats
• 9003-rseq-latency-histogram patch — 5-bucket abort latency histogram + avg_ns, ported from 6.19.
• 1000 Hz timer, dynamic preemption (CONFIG_PREEMPT_DYNAMIC=y).

Compiler & CPU Optimizations

• LTO Clang Full (CONFIG_LTO_CLANG_FULL=y) — whole-program link-time optimization via Clang.
• Per-variant CPU codegen — -march=native (laptop), -march=bdver2 (workpc), -march=skylake (pixel-slate), or -march=x86-64-v2 (generic).
• Built with Clang/LLVM-19 + ccache.

Storage, Memory, Network

• NVMe cluster-aware IRQ affinity — graduated to mainline in 7.0. Each NVMe queue pins 1:1 to a CPU.
• ZRAM (CONFIG_ZRAM=y, zstd compression).
• ZSWAP (CONFIG_ZSWAP=y, zstd compression, enabled by default).
• BBRv3 TCP congestion control (CONFIG_DEFAULT_TCP_CONG="bbr").

Security

• RANDSTRUCT Full (CONFIG_RANDSTRUCT_FULL=y) — randomized layouts for sensitive kernel structures. Requires NVIDIA driver to be re-patched after each driver package update (handled by scripts/nvidia-randstruct-fix.sh; only relevant to variants that run NVIDIA).

DKMS Modules (laptop variant)

• NVIDIA 610.43.02 — open kernel modules, with automatic RANDSTRUCT compatibility fixes.
• LenovoLegionLinux — pulled directly from upstream johnfanv2/LenovoLegionLinux master. The kernel patch 9100-platform-profile-accept-custom lets userspace (TLP, etc.) write custom to the aggregate /sys/firmware/acpi/platform_profile, replacing the need for an out-of-tree profile alias.
• xpadneo — advanced Xbox controller driver (rumble, battery reporting, low-latency).

Other variants don't ship DKMS modules — workpc has an AMD Radeon iGPU, pixel-slate and generic-build are configured for their target hardware in-tree.

Target Hardware (default variant)

• Device: Lenovo LOQ 15IRH8
• CPU: Intel i5-13420H (13th Gen, 8 cores / 12 threads)
• GPU: NVIDIA GeForce RTX 3050 6GB (Optimus — i915 display, NVIDIA render)
• RAM: 8 GB
• OS: Debian GNU/Linux 13 (trixie)

The build pipeline is parameterized; the master branch defaults to march=native for the LOQ. Other variants on their respective branches override codegen and driver subset.

Installation

Build from source

Pick the variant for your hardware:

git clone https://github.com/thewraith420/BobZKernel
cd BobZKernel

# Default (laptop, march=native) — master branch is already checked out
./scripts/update-and-build-7.2.sh

Other variants are on their own branches and build with whichever pipeline that branch is currently on — check out the branch first and run the script that's actually there (ls scripts/update-and-build-*.sh), since a variant branch may still be one major version behind master at any given time:

git checkout workpc        # AMD Piledriver
git checkout pixel-slate   # Google Pixel Slate
git checkout generic-build # Universal x86-64-v2

./scripts/update-and-build-7.1.sh   # or -7.2.sh, once that branch is migrated

The script handles 9 steps: detect latest v7.2.x tag → clean → apply patches → configure → build → install → NVIDIA DKMS check → LenovoLegionLinux DKMS update (upstream master) → summary.

First-time setup: if builds/linux-7.2/ doesn't exist, Step 1 auto-clones the stable kernel tree.

For unattended runs:

./scripts/update-and-build-7.2.sh --yes

To skip the kernel update check (use whatever's already checked out):

./scripts/update-and-build-7.2.sh --skip-update

Install on a different machine (portable installer)

When the build pipeline reaches Step 6, pick option 2 instead of installing locally:

./scripts/create-portable-installer-7.2.sh
# Or via the Step 6 prompt during update-and-build-7.2.sh

Produces a ~100-120 MB tarball. Copy to the target machine, then:

tar -xzf BobZKernel-*-installer.tar.gz
sudo ./install.sh

The installer auto-detects your distro and bootloader (Debian/Ubuntu/Mint, Fedora/RHEL, Arch/Manjaro, openSUSE).

Install pre-built (from GitHub Releases)

Pre-built tarballs for the variants above are attached to their respective releases — see the Hardware variants table.

Verification

After reboot, expected state on the laptop variant:

uname -r
# 7.2.2-BobZKernel (or current point release)

# LTO + native CPU
grep -E "^CONFIG_LTO_CLANG_FULL|^CONFIG_X86_NATIVE_CPU" /boot/config-$(uname -r)

# BORE active
sudo sysctl kernel.sched_bore
# kernel.sched_bore = 1

# RSEQ slice extension + histogram
sudo cat /sys/kernel/debug/rseq/stats

# NVMe cluster-aware (each queue pinned to its own CPU)
grep nvme0q /proc/interrupts

# Lenovo platform profile choices
cat /sys/firmware/acpi/platform_profile_choices
# low-power balanced performance max-power custom

Patch Stack (7.2)

In patches/cachyos-7.2/:

• 0001-bore.patch — BORE scheduler (vanilla variant, no CONFIG_CACHY required).
• 9003-rseq-latency-histogram.patch — abort latency histogram (5 bins + avg_ns).
• 0001-acpi-call.patch, dkms-clang.patch — CachyOS support patches.
• 9100-platform-profile-accept-custom.patch — lets the aggregate /sys/firmware/acpi/platform_profile accept writes of custom (needed so TLP can drive the legion-laptop "custom" profile directly).

Going 7.1 → 7.2: nothing dropped, nothing refreshed. All five patches carried forward byte-for-byte and dry-run verified exact (zero fuzz/offset) against pristine v7.2.2 before this release — including 0001-bore.patch, which needed a hand refresh at the 7.1.5 point release. Checked upstream first, as always: neither CachyOS's kernel-patches repo nor firelzrd/bore-scheduler has published anything for the 7.x line.

Dropped going 7.0 → 7.1:

• 0001-rt-i915.patch — PREEMPT_RT compatibility shim. CachyOS dropped it for 7.1; we don't build PREEMPT_RT, so the IS_ENABLED guards compile-time-evaluate to true. The patch was a no-op for our config.
• 0001-cgroup-vram.patch — dmem cgroup VRAM controller. Already dropped in 7.0.11 (TTM stable backports broke it); CachyOS dropped it for 7.1 too. Not exercised on single-user laptop with no container GPU workloads.

Patches pending consideration:

• Per-thread RSEQ abort suppression (was 9004 on 6.19, exponential backoff 10ms → 320ms).
• Revocable Resource Management — pure infrastructure with no in-tree consumers; deliberately not ported forward past 6.18.

Directory Structure

BobZKernel/
├── builds/
│   └── linux-7.2/                  # Kernel source (gitignored — auto-cloned by build script)
├── scripts/
│   ├── update-and-build-7.2.sh     # Main pipeline (9 steps)
│   ├── build-kernel-7.2.sh         # Kernel build with LTO + ccache (per-branch KCFLAGS)
│   ├── install-kernel-7.2.sh       # Install with DKMS, initramfs, GRUB
│   ├── create-portable-installer-7.2.sh
│   ├── nvidia-randstruct-fix.sh    # Re-applies __no_randomize_layout post NVIDIA update
│   ├── configure-nvidia-suspend.sh
│   ├── monitor-rseq-stats.sh
│   └── ...                          # Plus assorted RSEQ/NVIDIA tooling
├── patches/
│   └── cachyos-7.2/                # 7.2 patch set
├── configs/
│   ├── config-7.2-march-native     # Laptop (Intel Raptor Lake)
│   ├── config-7.2-workpc           # AMD Piledriver + Radeon (on workpc branch, once migrated)
│   ├── config-7.2-pixel-slate      # Google Pixel Slate (on pixel-slate branch, once migrated)
│   └── config-7.2-generic          # Universal x86-64-v2 (on generic-build branch, once migrated)
├── CONTEXT/                         # Project documentation
│   ├── PROJECT-OVERVIEW.md
│   ├── BUILD-STATUS.md
│   ├── BUILD-TROUBLESHOOTING.md
│   └── QUICK-START.md
└── tests/
    └── rseq-slice-extension/        # RSEQ tests (carried over from 6.19)

Branch tags workpc-6.18-archive, generic-build-6.18-archive, pixel-slate-6.18-archive preserve each variant's pre-rebase tip from before the 7.1 migration. Historical branches linux-7.1, linux-7.0, linux-6.19, linux-6.18 remain available for reference — each frozen at its confirmed-working tip at the point master moved on to the next major version.

Troubleshooting

See CONTEXT/BUILD-TROUBLESHOOTING.md for detailed error solutions.

NVIDIA suspend crash after driver update — Run sudo scripts/nvidia-randstruct-fix.sh. RANDSTRUCT shuffles struct layouts each kernel build; the NVIDIA DKMS source needs __no_randomize_layout re-applied each time the driver package is updated.

LenovoLegionLinux platform_profile not showing up — On kernel 7.x the driver registers a virtual platform device. If /sys/class/platform-profile/ is empty, check dmesg | grep legion for probe errors; re-run the build script to pull the latest upstream LLL commit.

TLP config writes silently rejected — TLP doesn't validate, but the kernel does. Accepted profile names on Lenovo Legion/LOQ hardware: low-power, balanced, performance, max-power, custom. The custom profile (purple LED, AC power mode) requires patch 9100-platform-profile-accept-custom in the running kernel — without it the aggregate sysfs returns -EINVAL on any write of custom.

Step 7 NVIDIA DKMS failure after choosing portable installer — Expected and benign. Step 7 tries to verify NVIDIA DKMS against the kernel that was supposed to be installed locally; if you picked option 2 (portable installer) at Step 6, no kernel was actually installed on this machine, so Step 7 has nothing to find. The portable tarball is fine.

Credits

• Linux Kernel — Linus Torvalds and contributors.
• Thomas Gleixner — RSEQ time slice extension mechanism (graduated to mainline in 7.0).
• Masahito Suzuki — BORE CPU scheduler.
• Tzung-Bi Shih (Google) — Revocable resource management (6.18 backport).
• CachyOS Team — Performance patches.
• LLVM Project — Clang/LLVM compiler infrastructure.
• johnfanv2 and contributors — LenovoLegionLinux (upstream).
• atar-axis — xpadneo Xbox controller driver.

License

Linux kernel is licensed under GPLv2. Patches retain their respective upstream licenses.