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Diffstat (limited to 'third_party/abseil_cpp/absl/strings/internal/memutil_benchmark.cc')
| -rw-r--r-- | third_party/abseil_cpp/absl/strings/internal/memutil_benchmark.cc | 323 |
1 files changed, 0 insertions, 323 deletions
diff --git a/third_party/abseil_cpp/absl/strings/internal/memutil_benchmark.cc b/third_party/abseil_cpp/absl/strings/internal/memutil_benchmark.cc deleted file mode 100644 index dc95c3e5e5..0000000000 --- a/third_party/abseil_cpp/absl/strings/internal/memutil_benchmark.cc +++ /dev/null @@ -1,323 +0,0 @@ -// 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/internal/memutil.h" - -#include <algorithm> -#include <cstdlib> - -#include "benchmark/benchmark.h" -#include "absl/strings/ascii.h" - -// We fill the haystack with aaaaaaaaaaaaaaaaaa...aaaab. -// That gives us: -// - an easy search: 'b' -// - a medium search: 'ab'. That means every letter is a possible match. -// - a pathological search: 'aaaaaa.......aaaaab' (half as many a's as haytack) -// We benchmark case-sensitive and case-insensitive versions of -// three memmem implementations: -// - memmem() from memutil.h -// - search() from STL -// - memmatch(), a custom implementation using memchr and memcmp. -// Here are sample results: -// -// Run on (12 X 3800 MHz CPU s) -// CPU Caches: -// L1 Data 32K (x6) -// L1 Instruction 32K (x6) -// L2 Unified 256K (x6) -// L3 Unified 15360K (x1) -// ---------------------------------------------------------------- -// Benchmark Time CPU Iterations -// ---------------------------------------------------------------- -// BM_Memmem 3583 ns 3582 ns 196469 2.59966GB/s -// BM_MemmemMedium 13743 ns 13742 ns 50901 693.986MB/s -// BM_MemmemPathological 13695030 ns 13693977 ns 51 713.133kB/s -// BM_Memcasemem 3299 ns 3299 ns 212942 2.82309GB/s -// BM_MemcasememMedium 16407 ns 16406 ns 42170 581.309MB/s -// BM_MemcasememPathological 17267745 ns 17266030 ns 41 565.598kB/s -// BM_Search 1610 ns 1609 ns 431321 5.78672GB/s -// BM_SearchMedium 11111 ns 11110 ns 63001 858.414MB/s -// BM_SearchPathological 12117390 ns 12116397 ns 58 805.984kB/s -// BM_Searchcase 3081 ns 3081 ns 229949 3.02313GB/s -// BM_SearchcaseMedium 16003 ns 16001 ns 44170 595.998MB/s -// BM_SearchcasePathological 15823413 ns 15821909 ns 44 617.222kB/s -// BM_Memmatch 197 ns 197 ns 3584225 47.2951GB/s -// BM_MemmatchMedium 52333 ns 52329 ns 13280 182.244MB/s -// BM_MemmatchPathological 659799 ns 659727 ns 1058 14.4556MB/s -// BM_Memcasematch 5460 ns 5460 ns 127606 1.70586GB/s -// BM_MemcasematchMedium 32861 ns 32857 ns 21258 290.248MB/s -// BM_MemcasematchPathological 15154243 ns 15153089 ns 46 644.464kB/s -// BM_MemmemStartup 5 ns 5 ns 150821500 -// BM_SearchStartup 5 ns 5 ns 150644203 -// BM_MemmatchStartup 7 ns 7 ns 97068802 -// -// Conclusions: -// -// The following recommendations are based on the sample results above. However, -// we have found that the performance of STL search can vary significantly -// depending on compiler and standard library implementation. We recommend you -// run the benchmarks for yourself on relevant platforms. -// -// If you need case-insensitive, STL search is slightly better than memmem for -// all cases. -// -// Case-sensitive is more subtle: -// Custom memmatch is _very_ fast at scanning, so if you have very few possible -// matches in your haystack, that's the way to go. Performance drops -// significantly with more matches. -// -// STL search is slightly faster than memmem in the medium and pathological -// benchmarks. However, the performance of memmem is currently more dependable -// across platforms and build configurations. - -namespace { - -constexpr int kHaystackSize = 10000; -constexpr int64_t kHaystackSize64 = kHaystackSize; -const char* MakeHaystack() { - char* haystack = new char[kHaystackSize]; - for (int i = 0; i < kHaystackSize - 1; ++i) haystack[i] = 'a'; - haystack[kHaystackSize - 1] = 'b'; - return haystack; -} -const char* const kHaystack = MakeHaystack(); - -void BM_Memmem(benchmark::State& state) { - for (auto _ : state) { - benchmark::DoNotOptimize( - absl::strings_internal::memmem(kHaystack, kHaystackSize, "b", 1)); - } - state.SetBytesProcessed(kHaystackSize64 * state.iterations()); -} -BENCHMARK(BM_Memmem); - -void BM_MemmemMedium(benchmark::State& state) { - for (auto _ : state) { - benchmark::DoNotOptimize( - absl::strings_internal::memmem(kHaystack, kHaystackSize, "ab", 2)); - } - state.SetBytesProcessed(kHaystackSize64 * state.iterations()); -} -BENCHMARK(BM_MemmemMedium); - -void BM_MemmemPathological(benchmark::State& state) { - for (auto _ : state) { - benchmark::DoNotOptimize(absl::strings_internal::memmem( - kHaystack, kHaystackSize, kHaystack + kHaystackSize / 2, - kHaystackSize - kHaystackSize / 2)); - } - state.SetBytesProcessed(kHaystackSize64 * state.iterations()); -} -BENCHMARK(BM_MemmemPathological); - -void BM_Memcasemem(benchmark::State& state) { - for (auto _ : state) { - benchmark::DoNotOptimize( - absl::strings_internal::memcasemem(kHaystack, kHaystackSize, "b", 1)); - } - state.SetBytesProcessed(kHaystackSize64 * state.iterations()); -} -BENCHMARK(BM_Memcasemem); - -void BM_MemcasememMedium(benchmark::State& state) { - for (auto _ : state) { - benchmark::DoNotOptimize( - absl::strings_internal::memcasemem(kHaystack, kHaystackSize, "ab", 2)); - } - state.SetBytesProcessed(kHaystackSize64 * state.iterations()); -} -BENCHMARK(BM_MemcasememMedium); - -void BM_MemcasememPathological(benchmark::State& state) { - for (auto _ : state) { - benchmark::DoNotOptimize(absl::strings_internal::memcasemem( - kHaystack, kHaystackSize, kHaystack + kHaystackSize / 2, - kHaystackSize - kHaystackSize / 2)); - } - state.SetBytesProcessed(kHaystackSize64 * state.iterations()); -} -BENCHMARK(BM_MemcasememPathological); - -bool case_eq(const char a, const char b) { - return absl::ascii_tolower(a) == absl::ascii_tolower(b); -} - -void BM_Search(benchmark::State& state) { - for (auto _ : state) { - benchmark::DoNotOptimize(std::search(kHaystack, kHaystack + kHaystackSize, - kHaystack + kHaystackSize - 1, - kHaystack + kHaystackSize)); - } - state.SetBytesProcessed(kHaystackSize64 * state.iterations()); -} -BENCHMARK(BM_Search); - -void BM_SearchMedium(benchmark::State& state) { - for (auto _ : state) { - benchmark::DoNotOptimize(std::search(kHaystack, kHaystack + kHaystackSize, - kHaystack + kHaystackSize - 2, - kHaystack + kHaystackSize)); - } - state.SetBytesProcessed(kHaystackSize64 * state.iterations()); -} -BENCHMARK(BM_SearchMedium); - -void BM_SearchPathological(benchmark::State& state) { - for (auto _ : state) { - benchmark::DoNotOptimize(std::search(kHaystack, kHaystack + kHaystackSize, - kHaystack + kHaystackSize / 2, - kHaystack + kHaystackSize)); - } - state.SetBytesProcessed(kHaystackSize64 * state.iterations()); -} -BENCHMARK(BM_SearchPathological); - -void BM_Searchcase(benchmark::State& state) { - for (auto _ : state) { - benchmark::DoNotOptimize(std::search(kHaystack, kHaystack + kHaystackSize, - kHaystack + kHaystackSize - 1, - kHaystack + kHaystackSize, case_eq)); - } - state.SetBytesProcessed(kHaystackSize64 * state.iterations()); -} -BENCHMARK(BM_Searchcase); - -void BM_SearchcaseMedium(benchmark::State& state) { - for (auto _ : state) { - benchmark::DoNotOptimize(std::search(kHaystack, kHaystack + kHaystackSize, - kHaystack + kHaystackSize - 2, - kHaystack + kHaystackSize, case_eq)); - } - state.SetBytesProcessed(kHaystackSize64 * state.iterations()); -} -BENCHMARK(BM_SearchcaseMedium); - -void BM_SearchcasePathological(benchmark::State& state) { - for (auto _ : state) { - benchmark::DoNotOptimize(std::search(kHaystack, kHaystack + kHaystackSize, - kHaystack + kHaystackSize / 2, - kHaystack + kHaystackSize, case_eq)); - } - state.SetBytesProcessed(kHaystackSize64 * state.iterations()); -} -BENCHMARK(BM_SearchcasePathological); - -char* memcasechr(const char* s, int c, size_t slen) { - c = absl::ascii_tolower(c); - for (; slen; ++s, --slen) { - if (absl::ascii_tolower(*s) == c) return const_cast<char*>(s); - } - return nullptr; -} - -const char* memcasematch(const char* phaystack, size_t haylen, - const char* pneedle, size_t neelen) { - if (0 == neelen) { - return phaystack; // even if haylen is 0 - } - if (haylen < neelen) return nullptr; - - const char* match; - const char* hayend = phaystack + haylen - neelen + 1; - while ((match = static_cast<char*>( - memcasechr(phaystack, pneedle[0], hayend - phaystack)))) { - if (absl::strings_internal::memcasecmp(match, pneedle, neelen) == 0) - return match; - else - phaystack = match + 1; - } - return nullptr; -} - -void BM_Memmatch(benchmark::State& state) { - for (auto _ : state) { - benchmark::DoNotOptimize( - absl::strings_internal::memmatch(kHaystack, kHaystackSize, "b", 1)); - } - state.SetBytesProcessed(kHaystackSize64 * state.iterations()); -} -BENCHMARK(BM_Memmatch); - -void BM_MemmatchMedium(benchmark::State& state) { - for (auto _ : state) { - benchmark::DoNotOptimize( - absl::strings_internal::memmatch(kHaystack, kHaystackSize, "ab", 2)); - } - state.SetBytesProcessed(kHaystackSize64 * state.iterations()); -} -BENCHMARK(BM_MemmatchMedium); - -void BM_MemmatchPathological(benchmark::State& state) { - for (auto _ : state) { - benchmark::DoNotOptimize(absl::strings_internal::memmatch( - kHaystack, kHaystackSize, kHaystack + kHaystackSize / 2, - kHaystackSize - kHaystackSize / 2)); - } - state.SetBytesProcessed(kHaystackSize64 * state.iterations()); -} -BENCHMARK(BM_MemmatchPathological); - -void BM_Memcasematch(benchmark::State& state) { - for (auto _ : state) { - benchmark::DoNotOptimize(memcasematch(kHaystack, kHaystackSize, "b", 1)); - } - state.SetBytesProcessed(kHaystackSize64 * state.iterations()); -} -BENCHMARK(BM_Memcasematch); - -void BM_MemcasematchMedium(benchmark::State& state) { - for (auto _ : state) { - benchmark::DoNotOptimize(memcasematch(kHaystack, kHaystackSize, "ab", 2)); - } - state.SetBytesProcessed(kHaystackSize64 * state.iterations()); -} -BENCHMARK(BM_MemcasematchMedium); - -void BM_MemcasematchPathological(benchmark::State& state) { - for (auto _ : state) { - benchmark::DoNotOptimize(memcasematch(kHaystack, kHaystackSize, - kHaystack + kHaystackSize / 2, - kHaystackSize - kHaystackSize / 2)); - } - state.SetBytesProcessed(kHaystackSize64 * state.iterations()); -} -BENCHMARK(BM_MemcasematchPathological); - -void BM_MemmemStartup(benchmark::State& state) { - for (auto _ : state) { - benchmark::DoNotOptimize(absl::strings_internal::memmem( - kHaystack + kHaystackSize - 10, 10, kHaystack + kHaystackSize - 1, 1)); - } -} -BENCHMARK(BM_MemmemStartup); - -void BM_SearchStartup(benchmark::State& state) { - for (auto _ : state) { - benchmark::DoNotOptimize( - std::search(kHaystack + kHaystackSize - 10, kHaystack + kHaystackSize, - kHaystack + kHaystackSize - 1, kHaystack + kHaystackSize)); - } -} -BENCHMARK(BM_SearchStartup); - -void BM_MemmatchStartup(benchmark::State& state) { - for (auto _ : state) { - benchmark::DoNotOptimize(absl::strings_internal::memmatch( - kHaystack + kHaystackSize - 10, 10, kHaystack + kHaystackSize - 1, 1)); - } -} -BENCHMARK(BM_MemmatchStartup); - -} // namespace |