From: Eric Eisner <eric.d.eisner@gmail.com>
Date: Fri, 23 Sep 2011 16:18:10 +0000 (-0700)
Subject: suffixarray: add benchmarks for construction
X-Git-Tag: weekly.2011-10-06~110
X-Git-Url: http://www.git.cypherpunks.su/?a=commitdiff_plain;h=481e619c50219fda4118f644e966d1bbb0cd82c7;p=gostls13.git

suffixarray: add benchmarks for construction

R=gri, jeff
CC=golang-dev
https://golang.org/cl/5040048
---

diff --git a/src/pkg/index/suffixarray/suffixarray_test.go b/src/pkg/index/suffixarray/suffixarray_test.go
index 9b4d89f42e..aeac9770c4 100644
--- a/src/pkg/index/suffixarray/suffixarray_test.go
+++ b/src/pkg/index/suffixarray/suffixarray_test.go
@@ -257,6 +257,30 @@ func TestIndex(t *testing.T) {
 	}
 }
 
+// Of all possible inputs, the random bytes have the least amount of substring
+// repetition, and the repeated bytes have the most. For most algorithms,
+// the running time of every input will be between these two.
+func benchmarkNew(b *testing.B, random bool) {
+	b.StopTimer()
+	data := make([]byte, 1e6)
+	if random {
+		for i := range data {
+			data[i] = byte(rand.Intn(256))
+		}
+	}
+	b.StartTimer()
+	for i := 0; i < b.N; i++ {
+		New(data)
+	}
+}
+
+func BenchmarkNewIndexRandom(b *testing.B) {
+	benchmarkNew(b, true)
+}
+func BenchmarkNewIndexRepeat(b *testing.B) {
+	benchmarkNew(b, false)
+}
+
 func BenchmarkSaveRestore(b *testing.B) {
 	b.StopTimer()
 	r := rand.New(rand.NewSource(0x5a77a1)) // guarantee always same sequence