benchmark (slug)

slug.benchmark

slug.benchmark — micro-benchmarking for Slug functions

Provides tools to measure and compare the performance of Slug functions with statistical rigour. Each benchmark runs a warmup phase, calibrates iteration count to fill a target sample window, then collects multiple samples to compute percentile statistics.

Overhead from the benchmarking harness itself is measured and subtracted by default, giving a cleaner picture of the work under test.

Quick start

val { micro, printResult, compare, printCompareReport } = import("slug.benchmark")

val result = micro("string concat", fn() { "hello" + " " + "world" })
result /> printResult

Units

Results are reported in nanoseconds by default. Use UnitUs or UnitMs for slower workloads.

TOC

• UnitMs
• UnitNs
• UnitUs
• compare(nil)
• micro(name, workFn, warmupMs, sampleMs, samples, minIters, maxIters, subtractOverhead, unit)
• printCompareReport(report)
• printResult(res)

Constants

UnitMs

str slug.benchmark#UnitMs

UnitNs

str slug.benchmark#UnitNs

UnitUs

str slug.benchmark#UnitUs

Functions

compare(nil)

fn slug.benchmark#compare(nil) -> @num

benchmarks a list of named functions and returns results sorted by p50.

Each entry in benches must be a map with name (@str) and fun (@fn) fields. All benchmarks share the same timing parameters. Results include a ratio field showing performance relative to the fastest (lowest p50) entry.

Pass the result to printCompareReport for formatted console output.

val report = compare([
  { name: "concat", fun: fn() { "a" + "b" } },
  { name: "fmt",    fun: fn() { fmt("{}{}", "a", "b") } },
])
report /> printCompareReport

@effects(‘time’) nil

Effects: time

micro(name, workFn, warmupMs, sampleMs, samples, minIters, maxIters, subtractOverhead, unit)

fn slug.benchmark#micro(@str name, @fn workFn, @num warmupMs = 100, @num sampleMs = 200, @num samples = 20, @num minIters = 1, @num maxIters = 10000000, @bool subtractOverhead = true, @str unit = UnitNs) -> @map

runs a single micro-benchmark and returns a result map with statistics.

Warms up the JIT/runtime for warmupMs, then calibrates iteration count so each sample takes approximately sampleMs to collect. Runs samples measurements and computes percentile statistics on the results.

Returns a map with the shape:

{
  name, unit, itersPerSample, samples,
  stats: { min, p50, p90, p99, max, mean, stdev },
  raw:   { timesPerIter: [...] }
}

Pass the result to printResult for formatted console output.

@effects(‘time’)

Effects: time

printCompareReport(report)

fn slug.benchmark#printCompareReport(report) -> ?

prints a formatted comparison report to stdout.

Benchmark report
  concat         : p50 38 ns  x1.0
  fmt            : p50 91 ns  x2.4

printResult(res)

fn slug.benchmark#printResult(res) -> ?

prints a formatted summary of a micro result to stdout.

string concat
  p50: 42 ns  p90: 51  p99: 78
  mean: 44  stdev: 8  min: 38  max: 91
  iters/sample: 10000  samples: 20