61 lines · cpp
1//===----------------------------------------------------------------------===//2// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.3// See https://llvm.org/LICENSE.txt for license information.4// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception5//6//===----------------------------------------------------------------------===//7 8// UNSUPPORTED: c++03, c++11, c++14, c++179// UNSUPPORTED: no-filesystem, no-localization, no-tzdb10 11// XFAIL: libcpp-has-no-experimental-tzdb12// XFAIL: availability-tzdb-missing13 14#include <chrono>15 16#include "benchmark/benchmark.h"17 18// Benchmarks the performance of the UTC <-> system time conversions. These19// operations determine the sum of leap second insertions at a specific time.20 21static void BM_from_sys(benchmark::State& state) {22 std::chrono::sys_days date{std::chrono::July / 1 / state.range(0)};23 for (auto _ : state)24 benchmark::DoNotOptimize(std::chrono::utc_clock::from_sys(date));25}26 27BENCHMARK(BM_from_sys)28 ->Arg(1970) // before the first leap seconds29 ->Arg(1979) // in the first half of inserted leap seconds30 ->Arg(1993) // in the second half of inserted leap seconds31 ->Arg(2100); // after the last leap second32 33BENCHMARK(BM_from_sys)->Arg(1970)->Arg(1979)->Arg(1993)->Arg(2100)->Threads(4);34BENCHMARK(BM_from_sys)->Arg(1970)->Arg(1979)->Arg(1993)->Arg(2100)->Threads(16);35 36static void BM_to_sys(benchmark::State& state) {37 // 59 sec offset means we pass th UTC offset for the leap second; assuming38 // there won't be more than 59 leap seconds ever.39 std::chrono::utc_seconds date{40 std::chrono::sys_days{std::chrono::July / 1 / state.range(0)}.time_since_epoch() + std::chrono::seconds{59}};41 for (auto _ : state)42 benchmark::DoNotOptimize(std::chrono::utc_clock::to_sys(date));43}44 45BENCHMARK(BM_to_sys)46 ->Arg(1970) // before the first leap seconds47 ->Arg(1979) // in the first half of inserted leap seconds48 ->Arg(1993) // in the second half of inserted leap seconds49 ->Arg(2100); // after the last leap second50 51BENCHMARK(BM_to_sys)->Arg(1970)->Arg(1979)->Arg(1993)->Arg(2100)->Threads(4);52BENCHMARK(BM_to_sys)->Arg(1970)->Arg(1979)->Arg(1993)->Arg(2100)->Threads(16);53 54int main(int argc, char** argv) {55 benchmark::Initialize(&argc, argv);56 if (benchmark::ReportUnrecognizedArguments(argc, argv))57 return 1;58 59 benchmark::RunSpecifiedBenchmarks();60}61