[SDK] Add benchmark for base2 exponential histogram indexer (#2181)

sdk/test/metrics/BUILD

@@ -360,6 +360,21 @@ otel_cc_benchmark(
     ],
 )
 
+otel_cc_benchmark(
+    name = "base2_exponential_histogram_indexer_benchmark",
+    srcs = [
+        "base2_exponential_histogram_indexer_benchmark.cc",
+    ],
+    tags = [
+        "benchmark",
+        "metrics",
+        "test",
+    ],
+    deps = [
+        "metrics_common_test_utils",
+    ],
+)
+
 otel_cc_benchmark(
     name = "histogram_aggregation_benchmark",
     srcs = [

sdk/test/metrics/CMakeLists.txt

@@ -49,6 +49,12 @@ if(WITH_BENCHMARK)
   target_link_libraries(attributes_hashmap_benchmark benchmark::benchmark
                         ${CMAKE_THREAD_LIBS_INIT} opentelemetry_common)
 
+  add_executable(base2_exponential_histogram_indexer_benchmark
+                 base2_exponential_histogram_indexer_benchmark.cc)
+  target_link_libraries(
+    base2_exponential_histogram_indexer_benchmark benchmark::benchmark
+    opentelemetry_metrics ${CMAKE_THREAD_LIBS_INIT} opentelemetry_common)
+
   add_executable(histogram_aggregation_benchmark
                  histogram_aggregation_benchmark.cc)
   target_link_libraries(

sdk/test/metrics/base2_exponential_histogram_indexer_benchmark.cc

@@ -0,0 +1,65 @@
+// Copyright The OpenTelemetry Authors
+// SPDX-License-Identifier: Apache-2.0
+
+#include "opentelemetry/sdk/metrics/aggregation/base2_exponential_histogram_indexer.h"
+
+#include <benchmark/benchmark.h>
+#include <array>
+#include <random>
+
+using namespace opentelemetry::sdk::metrics;
+namespace
+{
+
+void BM_NewIndexer(benchmark::State &state)
+{
+  std::array<int, 1000> batch;
+  std::default_random_engine generator;
+  std::uniform_int_distribution<int> distribution(1, 32);
+
+  while (state.KeepRunningBatch(static_cast<benchmark::IterationCount>(batch.size())))
+  {
+    state.PauseTiming();
+    for (auto &value : batch)
+    {
+      value = distribution(generator);
+    }
+    state.ResumeTiming();
+
+    for (const auto value : batch)
+    {
+      benchmark::DoNotOptimize(Base2ExponentialHistogramIndexer(value));
+    }
+  }
+}
+
+BENCHMARK(BM_NewIndexer);
+
+void BM_ComputeIndex(benchmark::State &state)
+{
+  std::array<double, 1000> batch;
+  std::default_random_engine generator;
+  std::uniform_real_distribution<double> distribution(0, 1000);
+  Base2ExponentialHistogramIndexer indexer(static_cast<int32_t>(state.range(0)));
+
+  while (state.KeepRunningBatch(static_cast<benchmark::IterationCount>(batch.size())))
+  {
+    state.PauseTiming();
+    for (auto &value : batch)
+    {
+      value = distribution(generator);
+    }
+    state.ResumeTiming();
+
+    for (const auto value : batch)
+    {
+      benchmark::DoNotOptimize(indexer.ComputeIndex(value));
+    }
+  }
+}
+
+BENCHMARK(BM_ComputeIndex)->Arg(-1)->Arg(0)->Arg(1)->Arg(20);
+
+}  // namespace
+
+BENCHMARK_MAIN();