third-party/benchmark/test/perf_counters_test.cc

   1 #include <cstdarg>
   2 #undef NDEBUG
   3
   4 #include "../src/commandlineflags.h"
   5 #include "../src/perf_counters.h"
   6 #include "benchmark/benchmark.h"
   7 #include "output_test.h"
   8
   9 namespace benchmark {
  10
  11 BM_DECLARE_string(benchmark_perf_counters);
  12
  13 }  // namespace benchmark
  14
  15 static void BM_Simple(benchmark::State& state) {
  16   for (auto _ : state) {
  17     auto iterations = double(state.iterations()) * double(state.iterations());
  18     benchmark::DoNotOptimize(iterations);
  19   }
  20 }
  21 BENCHMARK(BM_Simple);
  22 ADD_CASES(TC_JSONOut, {{"\"name\": \"BM_Simple\",$"}});
  23
  24 const int kIters = 1000000;
  25
  26 void BM_WithoutPauseResume(benchmark::State& state) {
  27   int n = 0;
  28
  29   for (auto _ : state) {
  30     for (auto i = 0; i < kIters; ++i) {
  31       n = 1 - n;
  32       benchmark::DoNotOptimize(n);
  33     }
  34   }
  35 }
  36
  37 BENCHMARK(BM_WithoutPauseResume);
  38 ADD_CASES(TC_JSONOut, {{"\"name\": \"BM_WithoutPauseResume\",$"}});
  39
  40 void BM_WithPauseResume(benchmark::State& state) {
  41   int m = 0, n = 0;
  42
  43   for (auto _ : state) {
  44     for (auto i = 0; i < kIters; ++i) {
  45       n = 1 - n;
  46       benchmark::DoNotOptimize(n);
  47     }
  48
  49     state.PauseTiming();
  50     for (auto j = 0; j < kIters; ++j) {
  51       m = 1 - m;
  52       benchmark::DoNotOptimize(m);
  53     }
  54     state.ResumeTiming();
  55   }
  56 }
  57
  58 BENCHMARK(BM_WithPauseResume);
  59
  60 ADD_CASES(TC_JSONOut, {{"\"name\": \"BM_WithPauseResume\",$"}});
  61
  62 static void CheckSimple(Results const& e) {
  63   CHECK_COUNTER_VALUE(e, double, "CYCLES", GT, 0);
  64 }
  65
  66 double withoutPauseResumeInstrCount = 0.0;
  67 double withPauseResumeInstrCount = 0.0;
  68
  69 static void SaveInstrCountWithoutResume(Results const& e) {
  70   withoutPauseResumeInstrCount = e.GetAs<double>("INSTRUCTIONS");
  71 }
  72
  73 static void SaveInstrCountWithResume(Results const& e) {
  74   withPauseResumeInstrCount = e.GetAs<double>("INSTRUCTIONS");
  75 }
  76
  77 CHECK_BENCHMARK_RESULTS("BM_Simple", &CheckSimple);
  78 CHECK_BENCHMARK_RESULTS("BM_WithoutPauseResume", &SaveInstrCountWithoutResume);
  79 CHECK_BENCHMARK_RESULTS("BM_WithPauseResume", &SaveInstrCountWithResume);
  80
  81 int main(int argc, char* argv[]) {
  82   if (!benchmark::internal::PerfCounters::kSupported) {
  83     return 0;
  84   }
  85   benchmark::FLAGS_benchmark_perf_counters = "CYCLES,INSTRUCTIONS";
  86   benchmark::internal::PerfCounters::Initialize();
  87   RunOutputTests(argc, argv);
  88
  89   BM_CHECK_GT(withPauseResumeInstrCount, kIters);
  90   BM_CHECK_GT(withoutPauseResumeInstrCount, kIters);
  91   BM_CHECK_LT(withPauseResumeInstrCount, 1.5 * withoutPauseResumeInstrCount);
  92 }