tests/runtime: add benchmarks for runtime memhash

tests/runtime/memhash_test.go

@@ -0,0 +1,36 @@
+package main
+
+import (
+	"hash/maphash"
+	"strconv"
+	"testing"
+)
+
+var buf [8192]byte
+
+func BenchmarkMaphash(b *testing.B) {
+	var h maphash.Hash
+	benchmarkHash(b, "maphash", h)
+}
+
+func benchmarkHash(b *testing.B, str string, h maphash.Hash) {
+	var sizes = []int{1, 2, 3, 4, 5, 10, 20, 30, 40, 50, 60, 70, 80, 90, 100, 1024, 8192}
+	for _, n := range sizes {
+		b.Run(strconv.Itoa(n), func(b *testing.B) { benchmarkHashn(b, int64(n), h) })
+	}
+}
+
+var total uint64
+
+func benchmarkHashn(b *testing.B, size int64, h maphash.Hash) {
+	b.SetBytes(size)
+
+	sum := make([]byte, 4)
+
+	for i := 0; i < b.N; i++ {
+		h.Reset()
+		h.Write(buf[:size])
+		sum = h.Sum(sum[:0])
+		total += uint64(sum[0])
+	}
+}