Add protobuf benchmarks for varint encoding.

We add two sets of benchmarks:
1. This benchmark uses increasingly large Any messages, which are common for storage systems.
For database like services, which are agnostic to the type being stored, Proto2 extensions could be used.
However, Proto3 drops unknown fields and most of extensions, so Any must be used.
Any types are also used as the arbitrary payload mechanism for RPC metadata.
2. Another benchmark uses the barest possible proto, meant to show the overhead of the encoding system.
This is the default cost of encoding a proto with absolutely no fields.

PiperOrigin-RevId: 135044506

proto/encode_test.go

@@ -0,0 +1,83 @@
+// Go support for Protocol Buffers - Google's data interchange format
+//
+// Copyright 2010 The Go Authors.  All rights reserved.
+// https://github.com/golang/protobuf
+//
+// Redistribution and use in source and binary forms, with or without
+// modification, are permitted provided that the following conditions are
+// met:
+//
+//     * Redistributions of source code must retain the above copyright
+// notice, this list of conditions and the following disclaimer.
+//     * Redistributions in binary form must reproduce the above
+// copyright notice, this list of conditions and the following disclaimer
+// in the documentation and/or other materials provided with the
+// distribution.
+//     * Neither the name of Google Inc. nor the names of its
+// contributors may be used to endorse or promote products derived from
+// this software without specific prior written permission.
+//
+// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+
+package proto_test
+
+import (
+	"strconv"
+	"testing"
+
+	"github.com/golang/protobuf/proto"
+	tpb "github.com/golang/protobuf/proto/proto3_proto"
+	"google3/net/proto2/go/ptypes"
+)
+
+var (
+	blackhole []byte
+)
+
+// BenchmarkAny creates increasingly large arbitrary Any messages.  The type is always the
+// same.
+func BenchmarkAny(b *testing.B) {
+	data := make([]byte, 1<<20)
+	quantum := 1 << 10
+	for i := uint(0); i <= 10; i++ {
+		b.Run(strconv.Itoa(quantum<<i), func(b *testing.B) {
+			for k := 0; k < b.N; k++ {
+				inner := &tpb.Message{
+					Data: data[:quantum<<i],
+				}
+				outer, err := ptypes.MarshalAny(inner)
+				if err != nil {
+					b.Error("wrong encode", err)
+				}
+				raw, err := proto.Marshal(&tpb.Message{
+					Anything: outer,
+				})
+				if err != nil {
+					b.Error("wrong encode", err)
+				}
+				blackhole = raw
+			}
+		})
+	}
+}
+
+// BenchmarkEmpy measures the overhead of doing the minimal possible encode.
+func BenchmarkEmpy(b *testing.B) {
+	for i := 0; i < b.N; i++ {
+		raw, err := proto.Marshal(&tpb.Message{})
+		if err != nil {
+			b.Error("wrong encode", err)
+		}
+		blackhole = raw
+	}
+}