From: Robert Obryk <robryk@gmail.com>
Date: Fri, 29 Mar 2013 21:17:09 +0000 (-0700)
Subject: bytes: Benchmark Buffer's compactions
X-Git-Tag: go1.1rc2~265
X-Git-Url: http://www.git.cypherpunks.su/?a=commitdiff_plain;h=461e7b7d409dad9406ae1e876ad7032f4356f501;p=gostls13.git

bytes: Benchmark Buffer's compactions

This benchmark verifies that CL #8173043 reduces time spent
sliding the Buffer's contents.

Results without and with CL #8173043 applied:
benchmark                        old ns/op    new ns/op    delta
BenchmarkBufferFullSmallReads       755336       175054  -76.82%

R=golang-dev, bradfitz
CC=golang-dev
https://golang.org/cl/8174043
---

diff --git a/src/pkg/bytes/buffer_test.go b/src/pkg/bytes/buffer_test.go
index 5b0b8b50cf..75145b05e9 100644
--- a/src/pkg/bytes/buffer_test.go
+++ b/src/pkg/bytes/buffer_test.go
@@ -509,3 +509,19 @@ func BenchmarkBufferNotEmptyWriteRead(b *testing.B) {
 		}
 	}
 }
+
+// Check that we don't compact too often. From Issue 5154.
+func BenchmarkBufferFullSmallReads(b *testing.B) {
+	buf := make([]byte, 1024)
+	for i := 0; i < b.N; i++ {
+		var b Buffer
+		b.Write(buf)
+		for b.Len()+20 < b.Cap() {
+			b.Write(buf[:10])
+		}
+		for i := 0; i < 5<<10; i++ {
+			b.Read(buf[:1])
+			b.Write(buf[:1])
+		}
+	}
+}