[Performance] Benchmark AddCounter with FakeStatsPlugin and OTelPlugin (#37282)

Sample output:

```
➜  grpc git:(otel-metrics-benchmark) ✗ bazel-bin/test/cpp/microbenchmarks/bm_stats_plugin
WARNING: All log messages before absl::InitializeLog() is called are written to STDERR
I0000 00:00:1721695619.615582 2126186 config.cc:257] gRPC experiments enabled: call_status_override_on_cancellation, call_tracer_in_transport, event_engine_dns, event_engine_listener, monitoring_experiment, pick_first_new, trace_record_callops, work_serializer_clears_time_cache
2024-07-22T17:46:59-07:00
Running bazel-bin/test/cpp/microbenchmarks/bm_stats_plugin
Run on (48 X 2450 MHz CPU s)
CPU Caches:
  L1 Data 32 KiB (x24)
  L1 Instruction 32 KiB (x24)
  L2 Unified 512 KiB (x24)
  L3 Unified 32768 KiB (x3)
Load Average: 1.16, 0.85, 0.85
***WARNING*** Library was built as DEBUG. Timings may be affected.
---------------------------------------------------------------------------
Benchmark                                 Time             CPU   Iterations
---------------------------------------------------------------------------
BM_AddCounterWithFakeStatsPlugin       1738 ns         1738 ns       404265
BM_AddCounterWithOTelPlugin             757 ns          757 ns       928142
I0000 00:00:1721695621.304593 2126186 test_config.cc:186] TestEnvironment ends
```

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Closes #37282

COPYBARA_INTEGRATE_REVIEW=https://github.com/grpc/grpc/pull/37282 from yijiem:otel-metrics-benchmark eeba3dfb5e
PiperOrigin-RevId: 655286398

test/cpp/microbenchmarks/BUILD

@@ -394,3 +394,19 @@ grpc_cc_benchmark(
         "//test/core/test_util:grpc_test_util",
     ],
 )
+
+grpc_cc_benchmark(
+    name = "bm_stats_plugin",
+    srcs = ["bm_stats_plugin.cc"],
+    external_deps = [
+        "absl/strings",
+        "otel/sdk/src/metrics",
+    ],
+    deps = [
+        ":helpers",
+        "//src/core:metrics",
+        "//src/cpp/ext/otel:otel_plugin",
+        "//test/core/test_util:fake_stats_plugin",
+        "//test/core/test_util:grpc_test_util",
+    ],
+)

test/cpp/microbenchmarks/bm_stats_plugin.cc

@@ -0,0 +1,92 @@
+// Copyright 2024 The gRPC 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 <memory>
+
+#include <benchmark/benchmark.h>
+
+#include "absl/log/absl_check.h"
+#include "absl/strings/string_view.h"
+#include "opentelemetry/sdk/metrics/meter_provider.h"
+
+#include <grpcpp/ext/otel_plugin.h>
+
+#include "src/core/lib/event_engine/channel_args_endpoint_config.h"
+#include "src/core/telemetry/metrics.h"
+#include "test/core/test_util/fake_stats_plugin.h"
+#include "test/core/test_util/test_config.h"
+#include "test/cpp/microbenchmarks/helpers.h"
+#include "test/cpp/util/test_config.h"
+
+namespace {
+
+constexpr const absl::string_view kMetricName = "test.counter";
+
+const auto kCounterHandle =
+    grpc_core::GlobalInstrumentsRegistry::RegisterUInt64Counter(
+        kMetricName, "A simple test counter", "{count}", true)
+        .Build();
+
+void BM_AddCounterWithFakeStatsPlugin(benchmark::State& state) {
+  grpc_core::GlobalStatsPluginRegistryTestPeer::
+      ResetGlobalStatsPluginRegistry();
+  grpc_core::FakeStatsPluginBuilder().BuildAndRegister();
+  grpc_event_engine::experimental::ChannelArgsEndpointConfig endpoint_config;
+  auto stats_plugin_group =
+      grpc_core::GlobalStatsPluginRegistry::GetStatsPluginsForChannel(
+          grpc_core::experimental::StatsPluginChannelScope("", "",
+                                                           endpoint_config));
+  for (auto _ : state) {
+    stats_plugin_group.AddCounter(kCounterHandle, 1, {}, {});
+  }
+}
+BENCHMARK(BM_AddCounterWithFakeStatsPlugin);
+
+void BM_AddCounterWithOTelPlugin(benchmark::State& state) {
+  grpc_core::GlobalStatsPluginRegistryTestPeer::
+      ResetGlobalStatsPluginRegistry();
+  auto meter_provider =
+      std::make_shared<opentelemetry::sdk::metrics::MeterProvider>();
+  auto status = grpc::OpenTelemetryPluginBuilder()
+                    .EnableMetrics({kMetricName})
+                    .SetMeterProvider(std::move(meter_provider))
+                    .BuildAndRegisterGlobal();
+  CHECK(status.ok());
+  grpc_event_engine::experimental::ChannelArgsEndpointConfig endpoint_config;
+  auto stats_plugin_group =
+      grpc_core::GlobalStatsPluginRegistry::GetStatsPluginsForChannel(
+          grpc_core::experimental::StatsPluginChannelScope("", "",
+                                                           endpoint_config));
+  for (auto _ : state) {
+    stats_plugin_group.AddCounter(kCounterHandle, 1, {}, {});
+  }
+}
+BENCHMARK(BM_AddCounterWithOTelPlugin);
+
+}  // namespace
+
+// Some distros have RunSpecifiedBenchmarks under the benchmark namespace,
+// and others do not. This allows us to support both modes.
+namespace benchmark {
+void RunTheBenchmarksNamespaced() { RunSpecifiedBenchmarks(); }
+}  // namespace benchmark
+
+int main(int argc, char** argv) {
+  grpc::testing::TestEnvironment env(&argc, argv);
+  LibraryInitializer libInit;
+  ::benchmark::Initialize(&argc, argv);
+  grpc::testing::InitTest(&argc, &argv, false);
+  benchmark::RunTheBenchmarksNamespaced();
+  return 0;
+}