pkg/fs: add benchmark for GetObject

This commit adds a benchmark for GetObject. It doesn't leverage the I/O
as much because it uses short text for data, just 58 chars.

pkg/fs/fs-object_test.go

@@ -0,0 +1,73 @@
+/*
+ * Minio Cloud Storage, (C) 2016 Minio, Inc.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package fs
+
+import (
+	"bytes"
+	"crypto/md5"
+	"encoding/base64"
+	"io/ioutil"
+	"os"
+	"strconv"
+	"testing"
+)
+
+func BenchmarkGetObject(b *testing.B) {
+	// Make a temporary directory to use as the filesystem.
+	directory, e := ioutil.TempDir("", "minio-benchmark-getobject")
+	if e != nil {
+		b.Fatal(e)
+	}
+	defer os.RemoveAll(directory)
+
+	// Create the filesystem.
+	filesystem, err := New(directory, 0)
+	if err != nil {
+		b.Fatal(err)
+	}
+
+	// Make a bucket and put in a few objects.
+	err = filesystem.MakeBucket("bucket")
+	if err != nil {
+		b.Fatal(err)
+	}
+
+	text := "Jack and Jill went up the hill / To fetch a pail of water."
+	hasher := md5.New()
+	hasher.Write([]byte(text))
+	sum := base64.StdEncoding.EncodeToString(hasher.Sum(nil))
+	for i := 0; i < 10; i++ {
+		_, err = filesystem.CreateObject("bucket", "object"+strconv.Itoa(i), sum, int64(len(text)), bytes.NewBufferString(text), nil)
+		if err != nil {
+			b.Fatal(err)
+		}
+	}
+
+	var w bytes.Buffer
+
+	b.ResetTimer()
+
+	for i := 0; i < b.N; i++ {
+		n, err := filesystem.GetObject(&w, "bucket", "object"+strconv.Itoa(i%10), 0, 0)
+		if err != nil {
+			b.Error(err)
+		}
+		if n != int64(len(text)) {
+			b.Errorf("GetObject returned incorrect length %d (should be %d)\n", n, int64(len(text)))
+		}
+	}
+}