golang-benchmark

**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. **Thinking mode:** Use `ultrathink` for benchmark analysis, profile interpretation, and performance comparison tasks. Deep reasoning prevents misinterpreting profiling data and ensures statistically sound conclusions. # Go Benchmarking & Performance Measurement Performance improvement does not exist without measures — if you can measure it, you can improve it. This 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. ## Writing Benchmarks ### `b.Loop()` (Go 1.24+) — preferred `b.Loop()` prevents the compiler from optimizing away the code under test — without it, the compiler can detect dead results and eliminate them, producing misleadingly fast numbers. It also excludes setup code before the loop from timing automatically. ```go func BenchmarkParse(b *testing.B) { data := loadFixture("large.json") // setup — excluded from timing for b.Loop() { Parse(data) // compiler cannot eliminate this call } } ``` Existing `for rang...