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// Benchmark utils
#include "../../bench_utils/bench_utils.hpp"

// rocThrust
#include <thrust/device_vector.h>
#include <thrust/execution_policy.h>
#include <thrust/merge.h>
#include <thrust/sort.h>

// Google Benchmark
#include <benchmark/benchmark.h>

// STL
#include <cstddef>
#include <string>
#include <vector>

struct basic
{
  template <typename T, typename Policy>
  float64_t
  run(thrust::device_vector<T>& in, thrust::device_vector<T>& out, const std::size_t elements_in_lhs, Policy policy)
  {
    thrust::merge(
      policy, in.cbegin(), in.cbegin() + elements_in_lhs, in.cbegin() + elements_in_lhs, in.cend(), out.begin());

    bench_utils::gpu_timer d_timer;

    d_timer.start(0);
    thrust::merge(
      policy, in.cbegin(), in.cbegin() + elements_in_lhs, in.cbegin() + elements_in_lhs, in.cend(), out.begin());
    d_timer.stop(0);

    return d_timer.get_duration();
  }
};

template <class Benchmark, class T>
void run_benchmark(benchmark::State& state,
                   const std::size_t elements,
                   const std::string seed_type,
                   const int entropy_reduction,
                   const std::size_t input_size_ratio)
{
  // Benchmark object
  Benchmark benchmark{};

  // GPU times
  std::vector<double> gpu_times;

  // Generate input
  const auto entropy         = bench_utils::get_entropy_percentage(entropy_reduction) / 100.0f;
  const auto elements_in_lhs = static_cast<std::size_t>(static_cast<double>(input_size_ratio * elements) / 100.0);

  thrust::device_vector<T> in = bench_utils::generate(elements, seed_type, entropy);

  thrust::sort(in.begin(), in.begin() + elements_in_lhs);
  thrust::sort(in.begin() + elements_in_lhs, in.end());

  // Output
  thrust::device_vector<T> out(elements);

  bench_utils::caching_allocator_t alloc{};
  thrust::detail::device_t policy{};

  for (auto _ : state)
  {
    float64_t duration = benchmark.template run<T>(in, out, elements_in_lhs, policy(alloc));
    state.SetIterationTime(duration);
    gpu_times.push_back(duration);
  }

  // BytesProcessed include read and written bytes, so when the BytesProcessed/s are reported
  // it will actually be the global memory bandwidth gotten.
  state.SetBytesProcessed(state.iterations() * 2 * elements * sizeof(T));
  state.SetItemsProcessed(state.iterations() * elements);

  const double gpu_cv         = bench_utils::StatisticsCV(gpu_times);
  state.counters["gpu_noise"] = gpu_cv;
}

#define CREATE_BENCHMARK(T, Elements, EntropyReduction, InputSizeRatio)                                     \
  benchmark::RegisterBenchmark(                                                                             \
    bench_utils::bench_naming::format_name(                                                                 \
      "{algo:merge,subalgo:" + name + ",input_type:" #T + ",elements:" + bench_utils::format_pow2(Elements) \
      + ",entropy:" + std::to_string(bench_utils::get_entropy_percentage(EntropyReduction))                 \
      + ",input_size_ratio:" #InputSizeRatio)                                                               \
      .c_str(),                                                                                             \
    run_benchmark<Benchmark, T>,                                                                            \
    Elements,                                                                                               \
    seed_type,                                                                                              \
    EntropyReduction,                                                                                       \
    InputSizeRatio)

#define BENCHMARK_ELEMENTS(type, elements, entropy)            \
  bs.push_back(CREATE_BENCHMARK(type, elements, entropy, 25)); \
  bs.push_back(CREATE_BENCHMARK(type, elements, entropy, 50)); \
  bs.push_back(CREATE_BENCHMARK(type, elements, entropy, 75));

#define BENCHMARK_TYPE_ENTROPY(type, entropy)                              \
  for (size_t size : bench_utils::sizes)                                   \
  {                                                                        \
    if (sizeof(type) * size <= bench_utils::system.devProp.totalGlobalMem) \
      BENCHMARK_ELEMENTS(type, size, entropy);                             \
  }
template <class Benchmark>
void add_benchmarks(
  const std::string& name, std::vector<benchmark::internal::Benchmark*>& benchmarks, const std::string seed_type)
{
  constexpr int entropy_reductions[] = {0, 4}; // 1.000, 0.201;

  for (int entropy_reduction : entropy_reductions)
  {
    std::vector<benchmark::internal::Benchmark*> bs;
    BENCHMARK_TYPE_ENTROPY(int8_t, entropy_reduction)
    BENCHMARK_TYPE_ENTROPY(int16_t, entropy_reduction)
    BENCHMARK_TYPE_ENTROPY(int32_t, entropy_reduction)
    BENCHMARK_TYPE_ENTROPY(int64_t, entropy_reduction)
#if THRUST_BENCHMARKS_HAVE_INT128_SUPPORT
    BENCHMARK_TYPE_ENTROPY(int128_t, entropy_reduction)
#endif
    BENCHMARK_TYPE_ENTROPY(float, entropy_reduction)
    BENCHMARK_TYPE_ENTROPY(double, entropy_reduction)
    benchmarks.insert(benchmarks.end(), bs.begin(), bs.end());
  }
}

int main(int argc, char* argv[])
{
  cli::Parser parser(argc, argv);
  parser.set_optional<std::string>("name_format", "name_format", "human", "either: json,human,txt");
  parser.set_optional<std::string>("seed", "seed", "random", bench_utils::get_seed_message());
  parser.run_and_exit_if_error();

  // Parse argv
  benchmark::Initialize(&argc, argv);
  bench_utils::bench_naming::set_format(parser.get<std::string>("name_format")); /* either: json,human,txt */
  const std::string seed_type = parser.get<std::string>("seed");

  // Benchmark info
  bench_utils::add_common_benchmark_info();
  benchmark::AddCustomContext("seed", seed_type);

  // Add benchmark
  std::vector<benchmark::internal::Benchmark*> benchmarks;
  add_benchmarks<basic>("basic", benchmarks, seed_type);

  // Use manual timing
  for (auto& b : benchmarks)
  {
    b->UseManualTime();
    b->Unit(benchmark::kMicrosecond);
    b->MinTime(0.4); // in seconds
  }

  // Run benchmarks
  benchmark::RunSpecifiedBenchmarks(bench_utils::ChooseCustomReporter());

  // Finish
  benchmark::Shutdown();
  return 0;
}