| // Copyright 2018 The Abseil Authors. |
| // |
| // Licensed under the Apache License, Version 2.0 (the "License"); |
| // you may not use this file except in compliance with the License. |
| // You may obtain a copy of the License at |
| // |
| // https://www.apache.org/licenses/LICENSE-2.0 |
| // |
| // Unless required by applicable law or agreed to in writing, software |
| // distributed under the License is distributed on an "AS IS" BASIS, |
| // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. |
| // See the License for the specific language governing permissions and |
| // limitations under the License. |
| |
| #include "absl/strings/charconv.h" |
| |
| #include <cstdlib> |
| #include <cstring> |
| #include <string> |
| |
| #include "benchmark/benchmark.h" |
| |
| namespace { |
| |
| void BM_Strtod_Pi(benchmark::State& state) { |
| const char* pi = "3.14159"; |
| for (auto s : state) { |
| benchmark::DoNotOptimize(pi); |
| benchmark::DoNotOptimize(strtod(pi, nullptr)); |
| } |
| } |
| BENCHMARK(BM_Strtod_Pi); |
| |
| void BM_Absl_Pi(benchmark::State& state) { |
| const char* pi = "3.14159"; |
| const char* pi_end = pi + strlen(pi); |
| for (auto s : state) { |
| benchmark::DoNotOptimize(pi); |
| double v; |
| absl::from_chars(pi, pi_end, v); |
| benchmark::DoNotOptimize(v); |
| } |
| } |
| BENCHMARK(BM_Absl_Pi); |
| |
| void BM_Strtod_Pi_float(benchmark::State& state) { |
| const char* pi = "3.14159"; |
| for (auto s : state) { |
| benchmark::DoNotOptimize(pi); |
| benchmark::DoNotOptimize(strtof(pi, nullptr)); |
| } |
| } |
| BENCHMARK(BM_Strtod_Pi_float); |
| |
| void BM_Absl_Pi_float(benchmark::State& state) { |
| const char* pi = "3.14159"; |
| const char* pi_end = pi + strlen(pi); |
| for (auto s : state) { |
| benchmark::DoNotOptimize(pi); |
| float v; |
| absl::from_chars(pi, pi_end, v); |
| benchmark::DoNotOptimize(v); |
| } |
| } |
| BENCHMARK(BM_Absl_Pi_float); |
| |
| void BM_Strtod_HardLarge(benchmark::State& state) { |
| const char* num = "272104041512242479.e200"; |
| for (auto s : state) { |
| benchmark::DoNotOptimize(num); |
| benchmark::DoNotOptimize(strtod(num, nullptr)); |
| } |
| } |
| BENCHMARK(BM_Strtod_HardLarge); |
| |
| void BM_Absl_HardLarge(benchmark::State& state) { |
| const char* numstr = "272104041512242479.e200"; |
| const char* numstr_end = numstr + strlen(numstr); |
| for (auto s : state) { |
| benchmark::DoNotOptimize(numstr); |
| double v; |
| absl::from_chars(numstr, numstr_end, v); |
| benchmark::DoNotOptimize(v); |
| } |
| } |
| BENCHMARK(BM_Absl_HardLarge); |
| |
| void BM_Strtod_HardSmall(benchmark::State& state) { |
| const char* num = "94080055902682397.e-242"; |
| for (auto s : state) { |
| benchmark::DoNotOptimize(num); |
| benchmark::DoNotOptimize(strtod(num, nullptr)); |
| } |
| } |
| BENCHMARK(BM_Strtod_HardSmall); |
| |
| void BM_Absl_HardSmall(benchmark::State& state) { |
| const char* numstr = "94080055902682397.e-242"; |
| const char* numstr_end = numstr + strlen(numstr); |
| for (auto s : state) { |
| benchmark::DoNotOptimize(numstr); |
| double v; |
| absl::from_chars(numstr, numstr_end, v); |
| benchmark::DoNotOptimize(v); |
| } |
| } |
| BENCHMARK(BM_Absl_HardSmall); |
| |
| void BM_Strtod_HugeMantissa(benchmark::State& state) { |
| std::string huge(200, '3'); |
| const char* num = huge.c_str(); |
| for (auto s : state) { |
| benchmark::DoNotOptimize(num); |
| benchmark::DoNotOptimize(strtod(num, nullptr)); |
| } |
| } |
| BENCHMARK(BM_Strtod_HugeMantissa); |
| |
| void BM_Absl_HugeMantissa(benchmark::State& state) { |
| std::string huge(200, '3'); |
| const char* num = huge.c_str(); |
| const char* num_end = num + 200; |
| for (auto s : state) { |
| benchmark::DoNotOptimize(num); |
| double v; |
| absl::from_chars(num, num_end, v); |
| benchmark::DoNotOptimize(v); |
| } |
| } |
| BENCHMARK(BM_Absl_HugeMantissa); |
| |
| std::string MakeHardCase(int length) { |
| // The number 1.1521...e-297 is exactly halfway between 12345 * 2**-1000 and |
| // the next larger representable number. The digits of this number are in |
| // the std::string below. |
| const std::string digits = |
| "1." |
| "152113937042223790993097181572444900347587985074226836242307364987727724" |
| "831384300183638649152607195040591791364113930628852279348613864894524591" |
| "272746490313676832900762939595690019745859128071117417798540258114233761" |
| "012939937017879509401007964861774960297319002612457273148497158989073482" |
| "171377406078223015359818300988676687994537274548940612510414856761641652" |
| "513434981938564294004070500716200446656421722229202383105446378511678258" |
| "370570631774499359748259931676320916632111681001853983492795053244971606" |
| "922718923011680846577744433974087653954904214152517799883551075537146316" |
| "168973685866425605046988661997658648354773076621610279716804960009043764" |
| "038392994055171112475093876476783502487512538082706095923790634572014823" |
| "78877699375152587890625" + |
| std::string(5000, '0'); |
| // generate the hard cases on either side for the given length. |
| // Lengths between 3 and 1000 are reasonable. |
| return digits.substr(0, length) + "1e-297"; |
| } |
| |
| void BM_Strtod_Big_And_Difficult(benchmark::State& state) { |
| std::string testcase = MakeHardCase(state.range(0)); |
| const char* begin = testcase.c_str(); |
| for (auto s : state) { |
| benchmark::DoNotOptimize(begin); |
| benchmark::DoNotOptimize(strtod(begin, nullptr)); |
| } |
| } |
| BENCHMARK(BM_Strtod_Big_And_Difficult)->Range(3, 5000); |
| |
| void BM_Absl_Big_And_Difficult(benchmark::State& state) { |
| std::string testcase = MakeHardCase(state.range(0)); |
| const char* begin = testcase.c_str(); |
| const char* end = begin + testcase.size(); |
| for (auto s : state) { |
| benchmark::DoNotOptimize(begin); |
| double v; |
| absl::from_chars(begin, end, v); |
| benchmark::DoNotOptimize(v); |
| } |
| } |
| BENCHMARK(BM_Absl_Big_And_Difficult)->Range(3, 5000); |
| |
| } // namespace |
| |
| // ------------------------------------------------------------------------ |
| // Benchmark Time CPU Iterations |
| // ------------------------------------------------------------------------ |
| // BM_Strtod_Pi 96 ns 96 ns 6337454 |
| // BM_Absl_Pi 35 ns 35 ns 20031996 |
| // BM_Strtod_Pi_float 91 ns 91 ns 7745851 |
| // BM_Absl_Pi_float 35 ns 35 ns 20430298 |
| // BM_Strtod_HardLarge 133 ns 133 ns 5288341 |
| // BM_Absl_HardLarge 181 ns 181 ns 3855615 |
| // BM_Strtod_HardSmall 279 ns 279 ns 2517243 |
| // BM_Absl_HardSmall 287 ns 287 ns 2458744 |
| // BM_Strtod_HugeMantissa 433 ns 433 ns 1604293 |
| // BM_Absl_HugeMantissa 160 ns 160 ns 4403671 |
| // BM_Strtod_Big_And_Difficult/3 236 ns 236 ns 2942496 |
| // BM_Strtod_Big_And_Difficult/8 232 ns 232 ns 2983796 |
| // BM_Strtod_Big_And_Difficult/64 437 ns 437 ns 1591951 |
| // BM_Strtod_Big_And_Difficult/512 1738 ns 1738 ns 402519 |
| // BM_Strtod_Big_And_Difficult/4096 3943 ns 3943 ns 176128 |
| // BM_Strtod_Big_And_Difficult/5000 4397 ns 4397 ns 157878 |
| // BM_Absl_Big_And_Difficult/3 39 ns 39 ns 17799583 |
| // BM_Absl_Big_And_Difficult/8 43 ns 43 ns 16096859 |
| // BM_Absl_Big_And_Difficult/64 550 ns 550 ns 1259717 |
| // BM_Absl_Big_And_Difficult/512 4167 ns 4167 ns 171414 |
| // BM_Absl_Big_And_Difficult/4096 9160 ns 9159 ns 76297 |
| // BM_Absl_Big_And_Difficult/5000 9738 ns 9738 ns 70140 |