Adding some basic extents construction benchmark

benchmarks/CMakeLists.txt

@@ -65,6 +65,7 @@ function(mdspan_add_openmp_benchmark EXENAME)
   endif()
 endfunction()
 
+add_subdirectory(extents)
 add_subdirectory(sum)
 add_subdirectory(matvec)
 add_subdirectory(copy)

benchmarks/extents/CMakeLists.txt

@@ -0,0 +1,2 @@
+
+mdspan_add_benchmark(extents_perf)

benchmarks/extents/extents_perf.cpp

@@ -0,0 +1,47 @@
+//@HEADER
+// ************************************************************************
+//
+//                        Kokkos v. 4.0
+//       Copyright (2022) National Technology & Engineering
+//               Solutions of Sandia, LLC (NTESS).
+//
+// Under the terms of Contract DE-NA0003525 with NTESS,
+// the U.S. Government retains certain rights in this software.
+//
+// Part of Kokkos, under the Apache License v2.0 with LLVM Exceptions.
+// See https://kokkos.org/LICENSE for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//@HEADER
+#include <experimental/mdspan>
+
+#include <benchmark/benchmark.h>
+
+#include "fill.hpp"
+
+using index_type = int;
+
+namespace stdex = std::experimental;
+_MDSPAN_INLINE_VARIABLE constexpr auto dyn = stdex::dynamic_extent;
+
+template <class Extents, class ... Args>
+void extents_construction(benchmark::State& state, Extents, int R, Args ... args) {
+  for ([[maybe_unused]] auto _ : state) {
+    double val =0;
+    for(int r=0; r<R; r++) {
+       Extents ext(args...);
+       val += ext.extent(0);
+    }
+    if(val<1.0*R*10) std::terminate();
+  }
+}
+
+BENCHMARK_CAPTURE(
+  extents_construction, int_int_int, stdex::dextents<int,3>(), 100000000, 100, 100, 100
+);
+
+BENCHMARK_CAPTURE(
+  extents_construction, array_int_3, stdex::dextents<int,3>(), 100000000, std::array<int,3>{100, 100, 100}
+);
+
+BENCHMARK_MAIN();