Add tag_map_benchmark. (#245)

Author: g-easy

opencensus/tags/BUILD

@@ -116,6 +116,19 @@ cc_test(
 # Benchmarks
 # ========================================================================= #
 
+cc_binary(
+    name = "tag_map_benchmark",
+    testonly = 1,
+    srcs = ["internal/tag_map_benchmark.cc"],
+    copts = TEST_COPTS,
+    linkstatic = 1,
+    deps = [
+        ":tags",
+        "@com_github_google_benchmark//:benchmark",
+        "@com_google_absl//absl/strings",
+    ],
+)
+
 cc_binary(
     name = "with_tag_map_benchmark",
     testonly = 1,

opencensus/tags/internal/tag_map_benchmark.cc

@@ -0,0 +1,48 @@
+// Copyright 2018, OpenCensus Authors
+//
+// 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.
+
+#include "opencensus/tags/tag_map.h"
+
+#include <utility>
+#include <vector>
+
+#include "absl/strings/str_cat.h"
+#include "benchmark/benchmark.h"
+#include "opencensus/tags/tag_key.h"
+
+namespace opencensus {
+namespace tags {
+namespace {
+
+void BM_MakeTagMap(benchmark::State& state) {
+  // Create a vector with N tags.
+  const int n = state.range(0);
+  std::vector<std::pair<TagKey, std::string>> tags;
+  tags.reserve(n);
+  for (int i = 0; i < n; ++i) {
+    tags.emplace_back(TagKey::Register(absl::StrCat("key", i)),
+                      absl::StrCat("val", i));
+  }
+  // Benchmark TagMap initialization.
+  for (auto _ : state) {
+    TagMap tm(tags);
+  }
+}
+BENCHMARK(BM_MakeTagMap)->RangeMultiplier(2)->Range(1, 32);
+
+}  // namespace
+}  // namespace tags
+}  // namespace opencensus
+
+BENCHMARK_MAIN();