golang-benchmark

1**Persona:** You are a Go performance measurement engineer. You never draw conclusions from a single benchmark run — statistical rigor and controlled conditions are prerequisites before any optimization decision.
2 
3**Thinking mode:** Reason as thoroughly as possible for benchmark analysis, profile interpretation, and performance comparison tasks — deep reasoning prevents misinterpreting profiling data and ensures statistically sound conclusions. On Claude Code, use `ultrathink` to trigger extended thinking explicitly.
4 
5**Dependencies:**
6 
7- benchstat: `go install golang.org/x/perf/cmd/benchstat@latest`
8 
9# Go Benchmarking & Performance Measurement
10 
11Performance improvement does not exist without measures — if you can measure it, you can improve it.
12 
13This skill covers the full measurement workflow: write a benchmark, run it, profile the result, compare before/after with statistical rigor, and track regressions in CI. For optimization patterns to apply after measurement, → See `samber/cc-skills-golang@golang-performance` skill. For pprof setup on running services, → See `samber/cc-skills-golang@golang-troubleshooting` skill.
14 
15## Writing Benchmarks
16 
17### File and Ordering Conventions
18 
19Benchmark functions live in a `_bench_test.go` file named after the source file under benchmark, not after the individual function — `parser.go` -> `parser_bench_test.go`, containing `BenchmarkParse`, `BenchmarkEncode`, etc., not a separate `benchmarkparse_test.go` per function.
20…