Cpu Cache Opt

Teaches Claude to diagnose and fix cache performance issues in C/C++ and Rust using perf counters, data layout transformations, and false sharing detection. You'd reach for this when your program shows high cache miss rates or when multithreaded code inexplicably runs slower than single-threaded. It walks through AoS to SoA conversions, cache line alignment, prefetching strategies, and loop blocking for matrix operations. The perf stat examples are immediately useful, showing exactly which counters matter and what thresholds indicate trouble. Honest take: cache optimization is one of those areas where measurement comes first, and this skill front-loads the profiling commands before suggesting fixes, which is the right order.

skills.sh installs: 709
GitHub stars: 279
last updated: Aug 21, 2026

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Install

$ npx -y skills add mohitmishra786/low-level-dev-skills --skill cpu-cache-opt --agent claude-code

Installs into .claude/skills of the current project.

Files

CPU Cache Optimization

Purpose

Guide agents through cache-aware programming: diagnosing cache misses with perf, data layout transformations (AoS→SoA), false sharing detection and fixes, prefetching, and cache-friendly algorithm design.

Triggers

"My program has high cache miss rates — how do I fix it?"
"What is false sharing and how do I detect it?"
"Should I use AoS or SoA data layout?"
"How do I measure cache performance with perf?"
"How do I use __builtin_prefetch?"
"My multithreaded program is slower than single-threaded due to cache"

Workflow

1. Measure cache performance

# Basic cache counters
perf stat -e cache-references,cache-misses,cycles,instructions ./prog

# L1/L2/L3 miss breakdown
perf stat -e \
    L1-dcache-load-misses,\
    L1-dcache-loads,\
    L2-dcache-load-misses,\
    LLC-load-misses,\
    LLC-loads \
    ./prog

# Cache miss rate = L1-dcache-load-misses / L1-dcache-loads
# > 5% is concerning; > 20% is severe

# False sharing detection
perf stat -e \
    machine_clears.memory_ordering,\
    mem_load_l3_hit_retired.xsnp_hitm \
    ./prog