Sample benchmark of PCG code

pcg_benchmark_vs_std_lib.cpp

/*
Sample output:

12/14/18 07:05:12
Running neuroevolution.exe
Run on (8 X 3492 MHz CPU s)
CPU Caches:
  L1 Data 32K (x4)
  L1 Instruction 32K (x4)
  L2 Unified 262K (x4)
  L3 Unified 8388K (x1)
-------------------------------------------------------
Benchmark                Time           CPU Iterations
-------------------------------------------------------
BM_Standard_RNG         51 ns         52 ns   10000000
BM_PCG_RNG               2 ns          2 ns  280000000
*/

#include <iostream>
#include <random>
#include <benchmark/benchmark.h>
#include "pcg_random.hpp"


static void BM_Standard_RNG(benchmark::State& state) {
  std::random_device rd;
  std::uniform_int_distribution<int> mt_uniform_distribution(0, 1024);

  for (auto _ : state) {
    mt_uniform_distribution(rd);
  }
}
BENCHMARK(BM_Standard_RNG);

static void BM_PCG_RNG(benchmark::State& state) {
  pcg_extras::seed_seq_from<std::random_device> pcg_seed_source;

  pcg32 rng(pcg_seed_source);

  std::uniform_int_distribution<> pcg_uniform_distribution(0, 1024);

  for (auto _ : state) {
    pcg_uniform_distribution(rng);
  }
}
BENCHMARK(BM_PCG_RNG);

BENCHMARK_MAIN();