diff options
Diffstat (limited to 'absl/flags/flag_benchmark.cc')
| -rw-r--r-- | absl/flags/flag_benchmark.cc | 44 |
1 files changed, 43 insertions, 1 deletions
diff --git a/absl/flags/flag_benchmark.cc b/absl/flags/flag_benchmark.cc index 7b52c9bc..57584f85 100644 --- a/absl/flags/flag_benchmark.cc +++ b/absl/flags/flag_benchmark.cc @@ -20,6 +20,8 @@ #include "absl/flags/flag.h" #include "absl/flags/marshalling.h" +#include "absl/flags/parse.h" +#include "absl/flags/reflection.h" #include "absl/strings/string_view.h" #include "absl/time/time.h" #include "absl/types/optional.h" @@ -101,7 +103,33 @@ std::string AbslUnparseFlag(const UDT&) { return ""; } #define FLAG_DEF(T) ABSL_FLAG(T, T##_flag, {}, ""); +#if defined(__clang__) && defined(__linux__) +// Force the flags used for benchmarks into a separate ELF section. +// This ensures that, even when other parts of the code might change size, +// the layout of the flags across cachelines is kept constant. This makes +// benchmark results more reproducible across unrelated code changes. +#pragma clang section data = ".benchmark_flags" +#endif BENCHMARKED_TYPES(FLAG_DEF) +#if defined(__clang__) && defined(__linux__) +#pragma clang section data = "" +#endif +// Register thousands of flags to bloat up the size of the registry. +// This mimics real life production binaries. +#define DEFINE_FLAG_0(name) ABSL_FLAG(int, name, 0, ""); +#define DEFINE_FLAG_1(name) DEFINE_FLAG_0(name##0) DEFINE_FLAG_0(name##1) +#define DEFINE_FLAG_2(name) DEFINE_FLAG_1(name##0) DEFINE_FLAG_1(name##1) +#define DEFINE_FLAG_3(name) DEFINE_FLAG_2(name##0) DEFINE_FLAG_2(name##1) +#define DEFINE_FLAG_4(name) DEFINE_FLAG_3(name##0) DEFINE_FLAG_3(name##1) +#define DEFINE_FLAG_5(name) DEFINE_FLAG_4(name##0) DEFINE_FLAG_4(name##1) +#define DEFINE_FLAG_6(name) DEFINE_FLAG_5(name##0) DEFINE_FLAG_5(name##1) +#define DEFINE_FLAG_7(name) DEFINE_FLAG_6(name##0) DEFINE_FLAG_6(name##1) +#define DEFINE_FLAG_8(name) DEFINE_FLAG_7(name##0) DEFINE_FLAG_7(name##1) +#define DEFINE_FLAG_9(name) DEFINE_FLAG_8(name##0) DEFINE_FLAG_8(name##1) +#define DEFINE_FLAG_10(name) DEFINE_FLAG_9(name##0) DEFINE_FLAG_9(name##1) +#define DEFINE_FLAG_11(name) DEFINE_FLAG_10(name##0) DEFINE_FLAG_10(name##1) +#define DEFINE_FLAG_12(name) DEFINE_FLAG_11(name##0) DEFINE_FLAG_11(name##1) +DEFINE_FLAG_12(bloat_flag_); namespace { @@ -111,10 +139,24 @@ namespace { benchmark::DoNotOptimize(absl::GetFlag(FLAGS_##T##_flag)); \ } \ } \ - BENCHMARK(BM_GetFlag_##T); + BENCHMARK(BM_GetFlag_##T)->ThreadRange(1, 16); BENCHMARKED_TYPES(BM_GetFlag) +void BM_ThreadedFindCommandLineFlag(benchmark::State& state) { + char dummy[] = "dummy"; + char* argv[] = {dummy}; + // We need to ensure that flags have been parsed. That is where the registry + // is finalized. + absl::ParseCommandLine(1, argv); + + for (auto s : state) { + benchmark::DoNotOptimize( + absl::FindCommandLineFlag("bloat_flag_010101010101")); + } +} +BENCHMARK(BM_ThreadedFindCommandLineFlag)->ThreadRange(1, 16); + } // namespace #define InvokeGetFlag(T) \ |