docs: update examples/compbench for go1.21

results on my Apple M2 Pro laptop:

$ make analysis
benchstat -filter=".name:Multiple" -col="/lib" -row="/size" -table="/concurrency" results.txt
/concurrency: single
        │    randutil     │             weightedrand             │
        │     sec/op      │   sec/op     vs base                 │
1e1          455.70n ± 0%   19.16n ± 2%   -95.80% (p=0.000 n=10)
1e2          438.20n ± 0%   32.81n ± 0%   -92.51% (p=0.000 n=10)
1e3         1179.00n ± 0%   46.00n ± 0%   -96.10% (p=0.000 n=10)
1e4         6591.00n ± 1%   60.34n ± 0%   -99.08% (p=0.000 n=10)
1e5        61188.00n ± 0%   84.83n ± 0%   -99.86% (p=0.000 n=10)
1e6        631928.5n ± 1%   112.6n ± 2%   -99.98% (p=0.000 n=10)
1e7       6402254.0n ± 1%   240.7n ± 0%  -100.00% (p=0.000 n=10)
geomean       16.84µ        63.16n        -99.62%

/concurrency: parallel
        │     randutil     │             weightedrand             │
        │      sec/op      │   sec/op     vs base                 │
1e1          589.300n ± 0%   2.026n ± 1%   -99.66% (p=0.000 n=10)
1e2          490.000n ± 0%   3.337n ± 1%   -99.32% (p=0.000 n=10)
1e3          766.500n ± 0%   4.518n ± 1%   -99.41% (p=0.000 n=10)
1e4          808.700n ± 0%   5.951n ± 2%   -99.26% (p=0.000 n=10)
1e5         6438.500n ± 1%   8.184n ± 1%   -99.87% (p=0.000 n=10)
1e6        108285.50n ± 1%   12.00n ± 1%   -99.99% (p=0.000 n=10)
1e7       2011263.00n ± 2%   28.95n ± 1%  -100.00% (p=0.000 n=10)
geomean        5.907µ        6.548n        -99.89%

examples/compbench/.gitignore

@@ -0,0 +1 @@
+results.txt

examples/compbench/Makefile

@@ -0,0 +1,12 @@
+.PHONY: analysis clean
+FILE=results.txt
+COUNT=10
+
+analysis: $(FILE)
+ benchstat -filter=".name:Multiple" -col="/lib" -row="/size" -table="/concurrency" $<
+
+clean:
+ rm -f $(FILE)
+
+$(FILE):
+ go test -bench=. -count=${COUNT} | tee $@

examples/compbench/bench_test.go

@@ -3,10 +3,10 @@
 package compbench
 
 import (
+ "fmt"
+ "math"
  "math/rand"
- "strconv"
  "testing"
- "time"
 
  "github.com/jmcvetta/randutil"
  "github.com/mroth/weightedrand/v2"
@@ -16,86 +16,85 @@ const BMMinChoices = 10
 const BMMaxChoices = 10_000_000
 
 func BenchmarkMultiple(b *testing.B) {
- b.Run("jmc_randutil", func(b *testing.B) {
- for n := BMMinChoices; n <= BMMaxChoices; n *= 10 {
- b.Run(strconv.Itoa(n), func(b *testing.B) {
- choices := convertChoices(b, mockChoices(b, n))
- b.ResetTimer()
- for i := 0; i < b.N; i++ {
- randutil.WeightedChoice(choices)
- }
- })
- }
- })
-
- b.Run("weightedrand", func(b *testing.B) {
- for n := BMMinChoices; n <= BMMaxChoices; n *= 10 {
- b.Run(strconv.Itoa(n), func(b *testing.B) {
- choices := mockChoices(b, n)
- chs, err := weightedrand.NewChooser(choices...)
- if err != nil {
- b.Fatal(err)
- }
- b.ResetTimer()
- for i := 0; i < b.N; i++ {
- chs.Pick()
- }
+ for n := BMMinChoices; n <= BMMaxChoices; n *= 10 {
+ b.Run(fmt.Sprintf("size=%s", fmt1eN(n)), func(b *testing.B) {
+ wr_choices := mockChoices(b, n)
+ ru_choices := convertChoices(b, wr_choices)
+
+ b.Run("concurrency=single", func(b *testing.B) {
+ b.Run("lib=randutil", func(b *testing.B) {
+ for i := 0; i < b.N; i++ {
+ randutil.WeightedChoice(ru_choices)
+ }
+ })
+
+ b.Run("lib=weightedrand", func(b *testing.B) {
+ chs, err := weightedrand.NewChooser(wr_choices...)
+ if err != nil {
+ b.Fatal(err)
+ }
+ b.ResetTimer()
+
+ for i := 0; i < b.N; i++ {
+ chs.Pick()
+ }
+ })
  })
- }
- })
-
- b.Run("wr-parallel", func(b *testing.B) {
- for n := BMMinChoices; n <= BMMaxChoices; n *= 10 {
- b.Run(strconv.Itoa(n), func(b *testing.B) {
- choices := mockChoices(b, n)
- chs, err := weightedrand.NewChooser(choices...)
- if err != nil {
- b.Fatal(err)
- }
- b.ResetTimer()
- b.RunParallel(func(pb *testing.PB) {
- rs := rand.New(rand.NewSource(time.Now().UTC().UnixNano()))
- for pb.Next() {
- chs.PickSource(rs)
+
+ b.Run("concurrency=parallel", func(b *testing.B) {
+ b.Run("lib=weightedrand", func(b *testing.B) {
+ chs, err := weightedrand.NewChooser(wr_choices...)
+ if err != nil {
+ b.Fatal(err)
  }
+ b.ResetTimer()
+
+ b.RunParallel(func(pb *testing.PB) {
+ for pb.Next() {
+ chs.Pick()
+ }
+ })
+ })
+
+ b.Run("lib=randutil", func(b *testing.B) {
+ b.RunParallel(func(pb *testing.PB) {
+ for pb.Next() {
+ randutil.WeightedChoice(ru_choices)
+ }
+ })
  })
  })
- }
- })
+ })
+ }
 }
 
-// The single usage case is an anti-pattern for the intended usage of this
-// library. Might as well keep some optional benchmarks for that to illustrate
-// the point.
+// THE SINGLE USAGE CASE IS AN ANTI-PATTERN FOR THE INTENDED USAGE OF THIS
+// LIBRARY. Provide some optional benchmarks for that to illustrate the point.
 func BenchmarkSingle(b *testing.B) {
  if testing.Short() {
  b.Skip()
  }
 
- b.Run("jmc_randutil", func(b *testing.B) {
- for n := BMMinChoices; n <= BMMaxChoices; n *= 10 {
- b.Run(strconv.Itoa(n), func(b *testing.B) {
- choices := convertChoices(b, mockChoices(b, n))
- b.ResetTimer()
+ for n := BMMinChoices; n <= BMMaxChoices; n *= 10 {
+ b.Run(fmt.Sprintf("size=%s", fmt1eN(n)), func(b *testing.B) {
+ wr_choices := mockChoices(b, n)
+ ru_choices := convertChoices(b, wr_choices)
+
+ b.Run("lib=randutil", func(b *testing.B) {
  for i := 0; i < b.N; i++ {
- randutil.WeightedChoice(choices)
+ randutil.WeightedChoice(ru_choices)
  }
  })
- }
- })
-
- b.Run("weightedrand", func(b *testing.B) {
- for n := BMMinChoices; n <= BMMaxChoices; n *= 10 {
- b.Run(strconv.Itoa(n), func(b *testing.B) {
- choices := mockChoices(b, n)
- b.ResetTimer()
+
+ b.Run("lib=weightedrand", func(b *testing.B) {
  for i := 0; i < b.N; i++ {
- chs, _ := weightedrand.NewChooser(choices...)
+ // never actually do this, this is not how the library is used
+ chs, _ := weightedrand.NewChooser(wr_choices...)
  chs.Pick()
  }
  })
- }
- })
+ })
+ }
 }
 
 func mockChoices(tb testing.TB, n int) []weightedrand.Choice[rune, uint] {
@@ -118,3 +117,9 @@ func convertChoices(tb testing.TB, cs []weightedrand.Choice[rune, uint]) []randu
  }
  return res
 }
+
+// fmt1eN returns simplified order of magnitude scientific notation for n,
+// e.g. "1e2" for 100, "1e7" for 10 million.
+func fmt1eN(n int) string {
+ return fmt.Sprintf("1e%d", int(math.Log10(float64(n))))
+}

examples/compbench/go.mod

@@ -1,6 +1,6 @@
 module github.com/mroth/weightedrand/examples/compbench
 
-go 1.18
+go 1.21
 
 require (
  github.com/jmcvetta/randutil v0.0.0-20150817122601-2bb1b664bcff