[hist] Add microbenchmarks for RHistStats::Fill

Author: hahnjo

hist/histv7/benchmark/CMakeLists.txt

@@ -6,3 +6,6 @@ target_link_libraries(hist_benchmark_engine ROOTHist benchmark::benchmark)
 
 add_executable(hist_benchmark_regular hist_benchmark_regular.cxx)
 target_link_libraries(hist_benchmark_regular ROOTHist benchmark::benchmark)
+
+add_executable(hist_benchmark_stats hist_benchmark_stats.cxx)
+target_link_libraries(hist_benchmark_stats ROOTHist benchmark::benchmark)

hist/histv7/benchmark/hist_benchmark_stats.cxx

@@ -0,0 +1,87 @@
+#include <ROOT/RHistStats.hxx>
+#include <ROOT/RWeight.hxx>
+
+#include <benchmark/benchmark.h>
+
+#include <random>
+#include <vector>
+
+struct RHistStats1 : public benchmark::Fixture {
+   // The object is stored and constructed in the fixture to avoid compiler optimizations in the benchmark body taking
+   // advantage of the (constant) constructor parameters.
+   ROOT::Experimental::RHistStats stats{1};
+   std::vector<double> fNumbers;
+
+   // Avoid GCC warning
+   using benchmark::Fixture::SetUp;
+   void SetUp(benchmark::State &state) final
+   {
+      std::mt19937 gen;
+      std::uniform_real_distribution<> dis;
+      fNumbers.resize(state.range(0));
+      for (std::size_t i = 0; i < fNumbers.size(); i++) {
+         fNumbers[i] = dis(gen);
+      }
+   }
+};
+
+BENCHMARK_DEFINE_F(RHistStats1, Fill)(benchmark::State &state)
+{
+   for (auto _ : state) {
+      for (double number : fNumbers) {
+         stats.Fill(number);
+      }
+   }
+}
+BENCHMARK_REGISTER_F(RHistStats1, Fill)->Range(0, 32768);
+
+BENCHMARK_DEFINE_F(RHistStats1, FillWeight)(benchmark::State &state)
+{
+   for (auto _ : state) {
+      for (double number : fNumbers) {
+         stats.Fill(number, ROOT::Experimental::RWeight(0.8));
+      }
+   }
+}
+BENCHMARK_REGISTER_F(RHistStats1, FillWeight)->Range(0, 32768);
+
+struct RHistStats2 : public benchmark::Fixture {
+   // The object is stored and constructed in the fixture to avoid compiler optimizations in the benchmark body taking
+   // advantage of the (constant) constructor parameters.
+   ROOT::Experimental::RHistStats stats{2};
+   std::vector<double> fNumbers;
+
+   // Avoid GCC warning
+   using benchmark::Fixture::SetUp;
+   void SetUp(benchmark::State &state) final
+   {
+      std::mt19937 gen;
+      std::uniform_real_distribution<> dis;
+      fNumbers.resize(2 * state.range(0));
+      for (std::size_t i = 0; i < fNumbers.size(); i++) {
+         fNumbers[i] = dis(gen);
+      }
+   }
+};
+
+BENCHMARK_DEFINE_F(RHistStats2, Fill)(benchmark::State &state)
+{
+   for (auto _ : state) {
+      for (std::size_t i = 0; i < fNumbers.size(); i += 2) {
+         stats.Fill(fNumbers[i], fNumbers[i + 1]);
+      }
+   }
+}
+BENCHMARK_REGISTER_F(RHistStats2, Fill)->Range(0, 32768);
+
+BENCHMARK_DEFINE_F(RHistStats2, FillWeight)(benchmark::State &state)
+{
+   for (auto _ : state) {
+      for (std::size_t i = 0; i < fNumbers.size(); i += 2) {
+         stats.Fill(fNumbers[i], fNumbers[i + 1], ROOT::Experimental::RWeight(0.8));
+      }
+   }
+}
+BENCHMARK_REGISTER_F(RHistStats2, FillWeight)->Range(0, 32768);
+
+BENCHMARK_MAIN();