test: add a rudimentary benchmark

benchmark/README.md

@@ -0,0 +1,9 @@
+
+> Very rudimentary, for now.  Add more!
+
+You're welcome to upload your results with your CPU, especially if they differ from ours.
+
+## Benchmarking
+
+    go test benchmark/*.go -bench=.
+

benchmark/loops_test.go

@@ -0,0 +1,79 @@
+package benchmark
+
+// from https://github.com/piersy/iterate-slice-bench-go
+// with fixes (methink)
+
+import (
+	"testing"
+)
+
+var Val = uint64(42)
+var slice = make([]uint64, 500*500)
+
+func BenchmarkRangeReadSliceByIndex(b *testing.B) {
+	for i := 0; i < b.N; i++ {
+		for j, _ := range slice {
+			Val = slice[j] + 1
+		}
+	}
+}
+
+func BenchmarkRangeReadSliceByValue(b *testing.B) {
+	for i := 0; i < b.N; i++ {
+		for _, v := range slice {
+			Val = v + 1
+		}
+	}
+}
+
+func BenchmarkRangeWriteSlice(b *testing.B) {
+	for i := 0; i < b.N; i++ {
+		for j, _ := range slice {
+			slice[j] = Val + 1
+		}
+	}
+}
+
+func BenchmarkRangeReadAndWriteSlice(b *testing.B) {
+	for i := 0; i < b.N; i++ {
+		for j, v := range slice {
+			slice[j] = v + 1
+		}
+	}
+}
+
+func BenchmarkForIterReadSlice(b *testing.B) {
+	for i := 0; i < b.N; i++ {
+		l := len(slice)
+		for j := 0; j < l; j++ {
+			Val = slice[j] + 1
+		}
+	}
+}
+
+func BenchmarkForIterWriteSlice(b *testing.B) {
+	for i := 0; i < b.N; i++ {
+		l := len(slice)
+		for j := 0; j < l; j++ {
+			slice[j] = Val + 1
+		}
+	}
+}
+
+func BenchmarkForIterReadAndWriteSlice(b *testing.B) {
+	for i := 0; i < b.N; i++ {
+		l := len(slice)
+		for j := 0; j < l; j++ {
+			slice[j] = slice[j] + 1
+		}
+	}
+}
+
+func BenchmarkDecreasingForIterReadAndWriteSlice(b *testing.B) {
+	for i := 0; i < b.N; i++ {
+		l := len(slice)
+		for j := l - 1; j >= 0; j-- {
+			slice[j] = slice[j] + 1
+		}
+	}
+}

benchmark/loops_test_domi41.log

@@ -0,0 +1,13 @@
+goos: linux
+goarch: amd64
+cpu: Intel(R) Core(TM) i7-4790 CPU @ 3.60GHz
+BenchmarkRangeReadSliceByIndex-8                	    8845	    128883 ns/op
+BenchmarkRangeReadSliceByValue-8                	   14170	     86845 ns/op
+BenchmarkRangeWriteSlice-8                      	    8294	    149656 ns/op
+BenchmarkRangeReadAndWriteSlice-8               	    7885	    154031 ns/op
+BenchmarkForIterReadSlice-8                     	    9285	    131403 ns/op
+BenchmarkForIterWriteSlice-8                    	    8377	    151931 ns/op
+BenchmarkForIterReadAndWriteSlice-8             	    8504	    141878 ns/op
+BenchmarkDecreasingForIterReadAndWriteSlice-8   	    7491	    152724 ns/op
+PASS
+ok  	command-line-arguments	10.636s