benchmark/test/perf_counters_test.cc
Jesse Rosenstock e73915667c
State: Initialize counters with kAvgIteration in constructor (#1652)
* State: Initialize counters with kAvgIteration in constructor

Previously, `counters` was updated in `PauseTiming()` with
`counters[name] += Counter(measurement, kAvgIteration)`.

The first `counters[name]` call inserts a counter with no flags.

There is no `operator+=` for `Counter`, so the insertion is done
by converting the `Counter` to a `double`, then constructing a
`Counter` to insert from the `double`, which drops the flags.

Pre-insert the `Counter` with the correct flags, then only
update `Counter::value`.

Introduced in 1c64a36 ([perf-counters] Fix pause/resume (#1643)).

* perf_counters_test.cc: Don't divide by iterations

Perf counters are now divided by iterations, so dividing again
in the test is wrong.

* State: Fix shadowed param error

* benchmark.cc: Fix clang-tidy error

---------

Co-authored-by: dominic <510002+dmah42@users.noreply.github.com>
2023-08-21 15:35:42 +01:00

93 lines
2.3 KiB
C++

#include <cstdarg>
#undef NDEBUG
#include "../src/commandlineflags.h"
#include "../src/perf_counters.h"
#include "benchmark/benchmark.h"
#include "output_test.h"
namespace benchmark {
BM_DECLARE_string(benchmark_perf_counters);
} // namespace benchmark
static void BM_Simple(benchmark::State& state) {
for (auto _ : state) {
auto iterations = state.iterations();
benchmark::DoNotOptimize(iterations);
}
}
BENCHMARK(BM_Simple);
ADD_CASES(TC_JSONOut, {{"\"name\": \"BM_Simple\",$"}});
const int kIters = 1000000;
void BM_WithoutPauseResume(benchmark::State& state) {
int n = 0;
for (auto _ : state) {
for (auto i = 0; i < kIters; ++i) {
n = 1 - n;
benchmark::DoNotOptimize(n);
}
}
}
BENCHMARK(BM_WithoutPauseResume);
ADD_CASES(TC_JSONOut, {{"\"name\": \"BM_WithoutPauseResume\",$"}});
void BM_WithPauseResume(benchmark::State& state) {
int m = 0, n = 0;
for (auto _ : state) {
for (auto i = 0; i < kIters; ++i) {
n = 1 - n;
benchmark::DoNotOptimize(n);
}
state.PauseTiming();
for (auto j = 0; j < kIters; ++j) {
m = 1 - m;
benchmark::DoNotOptimize(m);
}
state.ResumeTiming();
}
}
BENCHMARK(BM_WithPauseResume);
ADD_CASES(TC_JSONOut, {{"\"name\": \"BM_WithPauseResume\",$"}});
static void CheckSimple(Results const& e) {
CHECK_COUNTER_VALUE(e, double, "CYCLES", GT, 0);
}
double withoutPauseResumeInstrCount = 0.0;
double withPauseResumeInstrCount = 0.0;
static void SaveInstrCountWithoutResume(Results const& e) {
withoutPauseResumeInstrCount = e.GetAs<double>("INSTRUCTIONS");
}
static void SaveInstrCountWithResume(Results const& e) {
withPauseResumeInstrCount = e.GetAs<double>("INSTRUCTIONS");
}
CHECK_BENCHMARK_RESULTS("BM_Simple", &CheckSimple);
CHECK_BENCHMARK_RESULTS("BM_WithoutPauseResume", &SaveInstrCountWithoutResume);
CHECK_BENCHMARK_RESULTS("BM_WithPauseResume", &SaveInstrCountWithResume);
int main(int argc, char* argv[]) {
if (!benchmark::internal::PerfCounters::kSupported) {
return 0;
}
benchmark::FLAGS_benchmark_perf_counters = "CYCLES,INSTRUCTIONS";
benchmark::internal::PerfCounters::Initialize();
RunOutputTests(argc, argv);
BM_CHECK_GT(withPauseResumeInstrCount, kIters);
BM_CHECK_GT(withoutPauseResumeInstrCount, kIters);
BM_CHECK_LT(withPauseResumeInstrCount, 1.5 * withoutPauseResumeInstrCount);
}