harness.h

   1 #pragma once
   2
   3 #include <chrono>
   4 #include <cstdint>
   5 #include <optional>
   6 #include <type_traits>
   7 #include <utility>
   8
   9 struct Config final
  10 {
  11     std::optional<std::uint32_t> thread_count;
  12     std::optional<std::uint64_t> iteration_count;
  13 };
  14
  15 template <typename Fn, typename Input,
  16           typename Output = std::invoke_result_t<Fn, Input>>
  17 class BenchHarness;
  18
  19 class BenchHarnessBase
  20 {
  21     template <typename Fn, typename Input, typename Output>
  22     friend class BenchHarness;
  23
  24   private:
  25     void base_run(Config config,
  26                   void (*fn)(BenchHarnessBase *bench_harness_base,
  27                              std::uint64_t iteration_count));
  28 };
  29
  30 template <typename Fn, typename Input>
  31 class BenchHarness<Fn, Input, std::invoke_result_t<Fn, Input>> final
  32     : private BenchHarnessBase
  33 {
  34   private:
  35     Fn fn;
  36
  37   public:
  38     void run(Config config)
  39     {
  40         base_run(config, [](BenchHarnessBase *bench_harness_base,
  41                             std::uint64_t iteration_count) {
  42             auto &fn = static_cast<BenchHarness *>(bench_harness_base)->fn;
  43             for (std::uint64_t i = 0; i < iteration_count; i++)
  44             {
  45                 Input input;
  46
  47                 // optimization barrier
  48                 asm("" : : "r"(std::addressof(input)) : "memory");
  49
  50                 auto output = fn(input);
  51
  52                 // optimization barrier
  53                 asm("" : : "r"(std::addressof(output)) : "memory");
  54             }
  55         });
  56     }
  57 };