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-rw-r--r--absl/strings/BUILD.bazel65
-rw-r--r--absl/strings/str_cat_benchmark.cc142
-rw-r--r--absl/strings/str_join_benchmark.cc98
-rw-r--r--absl/strings/str_replace_benchmark.cc124
-rw-r--r--absl/strings/str_split_benchmark.cc158
-rw-r--r--absl/strings/string_view_benchmark.cc331
-rw-r--r--absl/synchronization/mutex.h2
7 files changed, 919 insertions, 1 deletions
diff --git a/absl/strings/BUILD.bazel b/absl/strings/BUILD.bazel
index 1e52312b..cb21385a 100644
--- a/absl/strings/BUILD.bazel
+++ b/absl/strings/BUILD.bazel
@@ -173,6 +173,20 @@ cc_test(
)
cc_test(
+ name = "string_view_benchmark",
+ srcs = ["string_view_benchmark.cc"],
+ copts = ABSL_TEST_COPTS,
+ tags = ["benchmark"],
+ visibility = ["//visibility:private"],
+ deps = [
+ ":strings",
+ "//absl/base",
+ "//absl/base:core_headers",
+ "@com_github_google_benchmark//:benchmark",
+ ],
+)
+
+cc_test(
name = "string_view_test",
size = "small",
srcs = ["string_view_test.cc"],
@@ -201,6 +215,19 @@ cc_test(
)
cc_test(
+ name = "str_replace_benchmark",
+ srcs = ["str_replace_benchmark.cc"],
+ copts = ABSL_TEST_COPTS,
+ tags = ["benchmark"],
+ visibility = ["//visibility:private"],
+ deps = [
+ ":strings",
+ "//absl/base",
+ "@com_github_google_benchmark//:benchmark",
+ ],
+)
+
+cc_test(
name = "str_replace_test",
size = "small",
srcs = ["str_replace_test.cc"],
@@ -226,6 +253,19 @@ cc_test(
)
cc_test(
+ name = "str_split_benchmark",
+ srcs = ["str_split_benchmark.cc"],
+ copts = ABSL_TEST_COPTS,
+ tags = ["benchmark"],
+ visibility = ["//visibility:private"],
+ deps = [
+ ":strings",
+ "//absl/base",
+ "@com_github_google_benchmark//:benchmark",
+ ],
+)
+
+cc_test(
name = "ostringstream_test",
size = "small",
srcs = ["internal/ostringstream_test.cc"],
@@ -268,6 +308,19 @@ cc_test(
)
cc_test(
+ name = "str_join_benchmark",
+ srcs = ["str_join_benchmark.cc"],
+ copts = ABSL_TEST_COPTS,
+ tags = ["benchmark"],
+ visibility = ["//visibility:private"],
+ deps = [
+ ":strings",
+ "//absl/memory",
+ "@com_github_google_benchmark//:benchmark",
+ ],
+)
+
+cc_test(
name = "str_cat_test",
size = "small",
srcs = ["str_cat_test.cc"],
@@ -281,6 +334,18 @@ cc_test(
)
cc_test(
+ name = "str_cat_benchmark",
+ srcs = ["str_cat_benchmark.cc"],
+ copts = ABSL_TEST_COPTS,
+ tags = ["benchmark"],
+ visibility = ["//visibility:private"],
+ deps = [
+ ":strings",
+ "@com_github_google_benchmark//:benchmark",
+ ],
+)
+
+cc_test(
name = "numbers_test",
size = "small",
srcs = [
diff --git a/absl/strings/str_cat_benchmark.cc b/absl/strings/str_cat_benchmark.cc
new file mode 100644
index 00000000..1791410c
--- /dev/null
+++ b/absl/strings/str_cat_benchmark.cc
@@ -0,0 +1,142 @@
+// 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
+//
+// http://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/str_cat.h"
+
+#include <cstdint>
+#include <string>
+
+#include "benchmark/benchmark.h"
+#include "absl/strings/substitute.h"
+
+namespace {
+
+const char kStringOne[] = "Once Upon A Time, ";
+const char kStringTwo[] = "There was a std::string benchmark";
+
+// We want to include negative numbers in the benchmark, so this function
+// is used to count 0, 1, -1, 2, -2, 3, -3, ...
+inline int IncrementAlternatingSign(int i) {
+ return i > 0 ? -i : 1 - i;
+}
+
+void BM_Sum_By_StrCat(benchmark::State& state) {
+ int i = 0;
+ char foo[100];
+ for (auto _ : state) {
+ // NOLINTNEXTLINE(runtime/printf)
+ strcpy(foo, absl::StrCat(kStringOne, i, kStringTwo, i * 65536ULL).c_str());
+ int sum = 0;
+ for (char* f = &foo[0]; *f != 0; ++f) {
+ sum += *f;
+ }
+ benchmark::DoNotOptimize(sum);
+ i = IncrementAlternatingSign(i);
+ }
+}
+BENCHMARK(BM_Sum_By_StrCat);
+
+void BM_StrCat_By_snprintf(benchmark::State& state) {
+ int i = 0;
+ char on_stack[1000];
+ for (auto _ : state) {
+ snprintf(on_stack, sizeof(on_stack), "%s %s:%d", kStringOne, kStringTwo, i);
+ i = IncrementAlternatingSign(i);
+ }
+}
+BENCHMARK(BM_StrCat_By_snprintf);
+
+void BM_StrCat_By_Strings(benchmark::State& state) {
+ int i = 0;
+ for (auto _ : state) {
+ std::string result =
+ std::string(kStringOne) + " " + kStringTwo + ":" + absl::StrCat(i);
+ benchmark::DoNotOptimize(result);
+ i = IncrementAlternatingSign(i);
+ }
+}
+BENCHMARK(BM_StrCat_By_Strings);
+
+void BM_StrCat_By_StringOpPlus(benchmark::State& state) {
+ int i = 0;
+ for (auto _ : state) {
+ std::string result = kStringOne;
+ result += " ";
+ result += kStringTwo;
+ result += ":";
+ result += absl::StrCat(i);
+ benchmark::DoNotOptimize(result);
+ i = IncrementAlternatingSign(i);
+ }
+}
+BENCHMARK(BM_StrCat_By_StringOpPlus);
+
+void BM_StrCat_By_StrCat(benchmark::State& state) {
+ int i = 0;
+ for (auto _ : state) {
+ std::string result = absl::StrCat(kStringOne, " ", kStringTwo, ":", i);
+ benchmark::DoNotOptimize(result);
+ i = IncrementAlternatingSign(i);
+ }
+}
+BENCHMARK(BM_StrCat_By_StrCat);
+
+void BM_HexCat_By_StrCat(benchmark::State& state) {
+ int i = 0;
+ for (auto _ : state) {
+ std::string result =
+ absl::StrCat(kStringOne, " ", absl::Hex(int64_t{i} + 0x10000000));
+ benchmark::DoNotOptimize(result);
+ i = IncrementAlternatingSign(i);
+ }
+}
+BENCHMARK(BM_HexCat_By_StrCat);
+
+void BM_HexCat_By_Substitute(benchmark::State& state) {
+ int i = 0;
+ for (auto _ : state) {
+ std::string result = absl::Substitute(
+ "$0 $1", kStringOne, reinterpret_cast<void*>(int64_t{i} + 0x10000000));
+ benchmark::DoNotOptimize(result);
+ i = IncrementAlternatingSign(i);
+ }
+}
+BENCHMARK(BM_HexCat_By_Substitute);
+
+void BM_FloatToString_By_StrCat(benchmark::State& state) {
+ int i = 0;
+ float foo = 0.0f;
+ for (auto _ : state) {
+ std::string result = absl::StrCat(foo += 1.001f, " != ", int64_t{i});
+ benchmark::DoNotOptimize(result);
+ i = IncrementAlternatingSign(i);
+ }
+}
+BENCHMARK(BM_FloatToString_By_StrCat);
+
+void BM_DoubleToString_By_SixDigits(benchmark::State& state) {
+ int i = 0;
+ double foo = 0.0;
+ for (auto _ : state) {
+ std::string result =
+ absl::StrCat(absl::SixDigits(foo += 1.001), " != ", int64_t{i});
+ benchmark::DoNotOptimize(result);
+ i = IncrementAlternatingSign(i);
+ }
+}
+BENCHMARK(BM_DoubleToString_By_SixDigits);
+
+} // namespace
+
+BENCHMARK_MAIN();
diff --git a/absl/strings/str_join_benchmark.cc b/absl/strings/str_join_benchmark.cc
new file mode 100644
index 00000000..79cad5e3
--- /dev/null
+++ b/absl/strings/str_join_benchmark.cc
@@ -0,0 +1,98 @@
+//
+// 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
+//
+// http://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/str_join.h"
+
+#include <string>
+#include <vector>
+#include <utility>
+
+#include "benchmark/benchmark.h"
+
+namespace {
+
+void BM_Join2_Strings(benchmark::State& state) {
+ const int string_len = state.range(0);
+ const int num_strings = state.range(1);
+ const std::string s(string_len, 'x');
+ const std::vector<std::string> v(num_strings, s);
+ for (auto _ : state) {
+ std::string s = absl::StrJoin(v, "-");
+ benchmark::DoNotOptimize(s);
+ }
+}
+BENCHMARK(BM_Join2_Strings)
+ ->ArgPair(1 << 0, 1 << 3)
+ ->ArgPair(1 << 10, 1 << 3)
+ ->ArgPair(1 << 13, 1 << 3)
+ ->ArgPair(1 << 0, 1 << 10)
+ ->ArgPair(1 << 10, 1 << 10)
+ ->ArgPair(1 << 13, 1 << 10)
+ ->ArgPair(1 << 0, 1 << 13)
+ ->ArgPair(1 << 10, 1 << 13)
+ ->ArgPair(1 << 13, 1 << 13);
+
+void BM_Join2_Ints(benchmark::State& state) {
+ const int num_ints = state.range(0);
+ const std::vector<int> v(num_ints, 42);
+ for (auto _ : state) {
+ std::string s = absl::StrJoin(v, "-");
+ benchmark::DoNotOptimize(s);
+ }
+}
+BENCHMARK(BM_Join2_Ints)->Range(0, 1 << 13);
+
+void BM_Join2_KeysAndValues(benchmark::State& state) {
+ const int string_len = state.range(0);
+ const int num_pairs = state.range(1);
+ const std::string s(string_len, 'x');
+ const std::vector<std::pair<std::string, int>> v(num_pairs, std::make_pair(s, 42));
+ for (auto _ : state) {
+ std::string s = absl::StrJoin(v, ",", absl::PairFormatter("="));
+ benchmark::DoNotOptimize(s);
+ }
+}
+BENCHMARK(BM_Join2_KeysAndValues)
+ ->ArgPair(1 << 0, 1 << 3)
+ ->ArgPair(1 << 10, 1 << 3)
+ ->ArgPair(1 << 13, 1 << 3)
+ ->ArgPair(1 << 0, 1 << 10)
+ ->ArgPair(1 << 10, 1 << 10)
+ ->ArgPair(1 << 13, 1 << 10)
+ ->ArgPair(1 << 0, 1 << 13)
+ ->ArgPair(1 << 10, 1 << 13)
+ ->ArgPair(1 << 13, 1 << 13);
+
+void BM_JoinStreamable(benchmark::State& state) {
+ const int string_len = state.range(0);
+ const int num_strings = state.range(1);
+ const std::vector<std::string> v(num_strings, std::string(string_len, 'x'));
+ for (auto _ : state) {
+ std::string s = absl::StrJoin(v, "", absl::StreamFormatter());
+ benchmark::DoNotOptimize(s);
+ }
+}
+BENCHMARK(BM_JoinStreamable)
+ ->ArgPair(0, 0)
+ ->ArgPair(16, 1)
+ ->ArgPair(256, 1)
+ ->ArgPair(16, 16)
+ ->ArgPair(256, 16)
+ ->ArgPair(16, 256)
+ ->ArgPair(256, 256);
+
+} // namespace
+
+BENCHMARK_MAIN();
diff --git a/absl/strings/str_replace_benchmark.cc b/absl/strings/str_replace_benchmark.cc
new file mode 100644
index 00000000..9dd72eb6
--- /dev/null
+++ b/absl/strings/str_replace_benchmark.cc
@@ -0,0 +1,124 @@
+// 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
+//
+// http://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/str_replace.h"
+
+#include <cstring>
+#include <string>
+
+#include "benchmark/benchmark.h"
+#include "absl/base/internal/raw_logging.h"
+
+namespace {
+
+std::string* big_string;
+std::string* after_replacing_the;
+std::string* after_replacing_many;
+
+struct Replacement {
+ const char* needle;
+ const char* replacement;
+} replacements[] = {
+ {"the", "box"}, //
+ {"brown", "quick"}, //
+ {"jumped", "liquored"}, //
+ {"dozen", "brown"}, //
+ {"lazy", "pack"}, //
+ {"liquor", "shakes"}, //
+};
+
+// Here, we set up a std::string for use in global-replace benchmarks.
+// We started with a million blanks, and then deterministically insert
+// 10,000 copies each of two pangrams. The result is a std::string that is
+// 40% blank space and 60% these words. 'the' occurs 18,247 times and
+// all the substitutions together occur 49,004 times.
+//
+// We then create "after_replacing_the" to be a std::string that is a result of
+// replacing "the" with "box" in big_string.
+//
+// And then we create "after_replacing_many" to be a std::string that is result
+// of preferring several substitutions.
+void SetUpStrings() {
+ if (big_string == nullptr) {
+ size_t r = 0;
+ big_string = new std::string(1000 * 1000, ' ');
+ for (std::string phrase : {"the quick brown fox jumped over the lazy dogs",
+ "pack my box with the five dozen liquor jugs"}) {
+ for (int i = 0; i < 10 * 1000; ++i) {
+ r = r * 237 + 41; // not very random.
+ memcpy(&(*big_string)[r % (big_string->size() - phrase.size())],
+ phrase.data(), phrase.size());
+ }
+ }
+ // big_string->resize(50);
+ // OK, we've set up the std::string, now let's set up expectations - first by
+ // just replacing "the" with "box"
+ after_replacing_the = new std::string(*big_string);
+ for (size_t pos = 0;
+ (pos = after_replacing_the->find("the", pos)) != std::string::npos;) {
+ memcpy(&(*after_replacing_the)[pos], "box", 3);
+ }
+ // And then with all the replacements.
+ after_replacing_many = new std::string(*big_string);
+ for (size_t pos = 0;;) {
+ size_t next_pos = static_cast<size_t>(-1);
+ const char* needle_string = nullptr;
+ const char* replacement_string = nullptr;
+ for (const auto& r : replacements) {
+ auto needlepos = after_replacing_many->find(r.needle, pos);
+ if (needlepos != std::string::npos && needlepos < next_pos) {
+ next_pos = needlepos;
+ needle_string = r.needle;
+ replacement_string = r.replacement;
+ }
+ }
+ if (next_pos > after_replacing_many->size()) break;
+ after_replacing_many->replace(next_pos, strlen(needle_string),
+ replacement_string);
+ next_pos += strlen(replacement_string);
+ pos = next_pos;
+ }
+ }
+}
+
+void BM_StrReplaceAllOneReplacement(benchmark::State& state) {
+ SetUpStrings();
+ std::string src = *big_string;
+ for (auto _ : state) {
+ std::string dest = absl::StrReplaceAll(src, {{"the", "box"}});
+ ABSL_RAW_CHECK(dest == *after_replacing_the,
+ "not benchmarking intended behavior");
+ }
+}
+BENCHMARK(BM_StrReplaceAllOneReplacement);
+
+void BM_StrReplaceAll(benchmark::State& state) {
+ SetUpStrings();
+ std::string src = *big_string;
+ for (auto _ : state) {
+ std::string dest = absl::StrReplaceAll(src, {{"the", "box"},
+ {"brown", "quick"},
+ {"jumped", "liquored"},
+ {"dozen", "brown"},
+ {"lazy", "pack"},
+ {"liquor", "shakes"}});
+ ABSL_RAW_CHECK(dest == *after_replacing_many,
+ "not benchmarking intended behavior");
+ }
+}
+BENCHMARK(BM_StrReplaceAll);
+
+} // namespace
+
+BENCHMARK_MAIN();
diff --git a/absl/strings/str_split_benchmark.cc b/absl/strings/str_split_benchmark.cc
new file mode 100644
index 00000000..c35787b7
--- /dev/null
+++ b/absl/strings/str_split_benchmark.cc
@@ -0,0 +1,158 @@
+// 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
+//
+// http://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/str_split.h"
+
+#include <iterator>
+#include <string>
+#include <unordered_map>
+#include <unordered_set>
+#include <vector>
+
+#include "benchmark/benchmark.h"
+#include "absl/base/internal/raw_logging.h"
+#include "absl/strings/string_view.h"
+
+namespace {
+
+std::string MakeTestString(int desired_length) {
+ static const int kAverageValueLen = 25;
+ std::string test(desired_length * kAverageValueLen, 'x');
+ for (int i = 1; i < test.size(); i += kAverageValueLen) {
+ test[i] = ';';
+ }
+ return test;
+}
+
+void BM_Split2StringPiece(benchmark::State& state) {
+ std::string test = MakeTestString(state.range(0));
+ for (auto _ : state) {
+ std::vector<absl::string_view> result = absl::StrSplit(test, ';');
+ benchmark::DoNotOptimize(result);
+ }
+}
+BENCHMARK_RANGE(BM_Split2StringPiece, 0, 1 << 20);
+
+void BM_Split2StringPieceLifted(benchmark::State& state) {
+ std::string test = MakeTestString(state.range(0));
+ std::vector<absl::string_view> result;
+ for (auto _ : state) {
+ result = absl::StrSplit(test, ';');
+ }
+ benchmark::DoNotOptimize(result);
+}
+BENCHMARK_RANGE(BM_Split2StringPieceLifted, 0, 1 << 20);
+
+void BM_Split2String(benchmark::State& state) {
+ std::string test = MakeTestString(state.range(0));
+ for (auto _ : state) {
+ std::vector<std::string> result = absl::StrSplit(test, ';');
+ benchmark::DoNotOptimize(result);
+ }
+}
+BENCHMARK_RANGE(BM_Split2String, 0, 1 << 20);
+
+// This benchmark is for comparing Split2 to Split1 (SplitStringUsing). In
+// particular, this benchmark uses SkipEmpty() to match SplitStringUsing's
+// behavior.
+void BM_Split2SplitStringUsing(benchmark::State& state) {
+ std::string test = MakeTestString(state.range(0));
+ for (auto _ : state) {
+ std::vector<std::string> result = absl::StrSplit(test, ';', absl::SkipEmpty());
+ benchmark::DoNotOptimize(result);
+ }
+}
+BENCHMARK_RANGE(BM_Split2SplitStringUsing, 0, 1 << 20);
+
+void BM_SplitStringToUnorderedSet(benchmark::State& state) {
+ const int len = state.range(0);
+ std::string test(len, 'x');
+ for (int i = 1; i < len; i += 2) {
+ test[i] = ';';
+ }
+ for (auto _ : state) {
+ std::unordered_set<std::string> result =
+ absl::StrSplit(test, ':', absl::SkipEmpty());
+ benchmark::DoNotOptimize(result);
+ }
+}
+BENCHMARK_RANGE(BM_SplitStringToUnorderedSet, 0, 1 << 20);
+
+void BM_SplitStringToUnorderedMap(benchmark::State& state) {
+ const int len = state.range(0);
+ std::string test(len, 'x');
+ for (int i = 1; i < len; i += 2) {
+ test[i] = ';';
+ }
+ for (auto _ : state) {
+ std::unordered_map<std::string, std::string> result =
+ absl::StrSplit(test, ':', absl::SkipEmpty());
+ benchmark::DoNotOptimize(result);
+ }
+}
+BENCHMARK_RANGE(BM_SplitStringToUnorderedMap, 0, 1 << 20);
+
+void BM_SplitStringAllowEmpty(benchmark::State& state) {
+ const int len = state.range(0);
+ std::string test(len, 'x');
+ for (int i = 1; i < len; i += 2) {
+ test[i] = ';';
+ }
+ for (auto _ : state) {
+ std::vector<std::string> result = absl::StrSplit(test, ';');
+ benchmark::DoNotOptimize(result);
+ }
+}
+BENCHMARK_RANGE(BM_SplitStringAllowEmpty, 0, 1 << 20);
+
+struct OneCharLiteral {
+ char operator()() const { return 'X'; }
+};
+
+struct OneCharStringLiteral {
+ const char* operator()() const { return "X"; }
+};
+
+template <typename DelimiterFactory>
+void BM_SplitStringWithOneChar(benchmark::State& state) {
+ const auto delimiter = DelimiterFactory()();
+ std::vector<absl::string_view> pieces;
+ size_t v = 0;
+ for (auto _ : state) {
+ pieces = absl::StrSplit("The quick brown fox jumps over the lazy dog",
+ delimiter);
+ v += pieces.size();
+ }
+ ABSL_RAW_CHECK(v == state.iterations(), "");
+}
+BENCHMARK_TEMPLATE(BM_SplitStringWithOneChar, OneCharLiteral);
+BENCHMARK_TEMPLATE(BM_SplitStringWithOneChar, OneCharStringLiteral);
+
+template <typename DelimiterFactory>
+void BM_SplitStringWithOneCharNoVector(benchmark::State& state) {
+ const auto delimiter = DelimiterFactory()();
+ size_t v = 0;
+ for (auto _ : state) {
+ auto splitter = absl::StrSplit(
+ "The quick brown fox jumps over the lazy dog", delimiter);
+ v += std::distance(splitter.begin(), splitter.end());
+ }
+ ABSL_RAW_CHECK(v == state.iterations(), "");
+}
+BENCHMARK_TEMPLATE(BM_SplitStringWithOneCharNoVector, OneCharLiteral);
+BENCHMARK_TEMPLATE(BM_SplitStringWithOneCharNoVector, OneCharStringLiteral);
+
+} // namespace
+
+BENCHMARK_MAIN();
diff --git a/absl/strings/string_view_benchmark.cc b/absl/strings/string_view_benchmark.cc
new file mode 100644
index 00000000..c66f0fbd
--- /dev/null
+++ b/absl/strings/string_view_benchmark.cc
@@ -0,0 +1,331 @@
+// 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
+//
+// http://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/string_view.h"
+
+#include <algorithm>
+#include <cstdint>
+#include <map>
+#include <random>
+#include <string>
+#include <unordered_set>
+#include <vector>
+
+#include "benchmark/benchmark.h"
+#include "absl/base/attributes.h"
+#include "absl/base/internal/raw_logging.h"
+#include "absl/base/macros.h"
+#include "absl/strings/str_cat.h"
+
+namespace {
+
+// Provide a forcibly out-of-line wrapper for operator== that can be used in
+// benchmarks to measure the impact of inlining.
+ABSL_ATTRIBUTE_NOINLINE
+bool NonInlinedEq(absl::string_view a, absl::string_view b) { return a == b; }
+
+// We use functions that cannot be inlined to perform the comparison loops so
+// that inlining of the operator== can't optimize away *everything*.
+ABSL_ATTRIBUTE_NOINLINE
+void DoEqualityComparisons(benchmark::State& state, absl::string_view a,
+ absl::string_view b) {
+ for (auto _ : state) {
+ benchmark::DoNotOptimize(a == b);
+ }
+}
+
+void BM_EqualIdentical(benchmark::State& state) {
+ std::string x(state.range(0), 'a');
+ DoEqualityComparisons(state, x, x);
+}
+BENCHMARK(BM_EqualIdentical)->DenseRange(0, 3)->Range(4, 1 << 10);
+
+void BM_EqualSame(benchmark::State& state) {
+ std::string x(state.range(0), 'a');
+ std::string y = x;
+ DoEqualityComparisons(state, x, y);
+}
+BENCHMARK(BM_EqualSame)
+ ->DenseRange(0, 10)
+ ->Arg(20)
+ ->Arg(40)
+ ->Arg(70)
+ ->Arg(110)
+ ->Range(160, 4096);
+
+void BM_EqualDifferent(benchmark::State& state) {
+ const int len = state.range(0);
+ std::string x(len, 'a');
+ std::string y = x;
+ if (len > 0) {
+ y[len - 1] = 'b';
+ }
+ DoEqualityComparisons(state, x, y);
+}
+BENCHMARK(BM_EqualDifferent)->DenseRange(0, 3)->Range(4, 1 << 10);
+
+// This benchmark is intended to check that important simplifications can be
+// made with absl::string_view comparisons against constant strings. The idea is
+// that if constant strings cause redundant components of the comparison, the
+// compiler should detect and eliminate them. Here we use 8 different strings,
+// each with the same size. Provided our comparison makes the implementation
+// inline-able by the compiler, it should fold all of these away into a single
+// size check once per loop iteration.
+ABSL_ATTRIBUTE_NOINLINE
+void DoConstantSizeInlinedEqualityComparisons(benchmark::State& state,
+ absl::string_view a) {
+ for (auto _ : state) {
+ benchmark::DoNotOptimize(a == "aaa");
+ benchmark::DoNotOptimize(a == "bbb");
+ benchmark::DoNotOptimize(a == "ccc");
+ benchmark::DoNotOptimize(a == "ddd");
+ benchmark::DoNotOptimize(a == "eee");
+ benchmark::DoNotOptimize(a == "fff");
+ benchmark::DoNotOptimize(a == "ggg");
+ benchmark::DoNotOptimize(a == "hhh");
+ }
+}
+void BM_EqualConstantSizeInlined(benchmark::State& state) {
+ std::string x(state.range(0), 'a');
+ DoConstantSizeInlinedEqualityComparisons(state, x);
+}
+// We only need to check for size of 3, and <> 3 as this benchmark only has to
+// do with size differences.
+BENCHMARK(BM_EqualConstantSizeInlined)->DenseRange(2, 4);
+
+// This benchmark exists purely to give context to the above timings: this is
+// what they would look like if the compiler is completely unable to simplify
+// between two comparisons when they are comparing against constant strings.
+ABSL_ATTRIBUTE_NOINLINE
+void DoConstantSizeNonInlinedEqualityComparisons(benchmark::State& state,
+ absl::string_view a) {
+ for (auto _ : state) {
+ // Force these out-of-line to compare with the above function.
+ benchmark::DoNotOptimize(NonInlinedEq(a, "aaa"));
+ benchmark::DoNotOptimize(NonInlinedEq(a, "bbb"));
+ benchmark::DoNotOptimize(NonInlinedEq(a, "ccc"));
+ benchmark::DoNotOptimize(NonInlinedEq(a, "ddd"));
+ benchmark::DoNotOptimize(NonInlinedEq(a, "eee"));
+ benchmark::DoNotOptimize(NonInlinedEq(a, "fff"));
+ benchmark::DoNotOptimize(NonInlinedEq(a, "ggg"));
+ benchmark::DoNotOptimize(NonInlinedEq(a, "hhh"));
+ }
+}
+
+void BM_EqualConstantSizeNonInlined(benchmark::State& state) {
+ std::string x(state.range(0), 'a');
+ DoConstantSizeNonInlinedEqualityComparisons(state, x);
+}
+// We only need to check for size of 3, and <> 3 as this benchmark only has to
+// do with size differences.
+BENCHMARK(BM_EqualConstantSizeNonInlined)->DenseRange(2, 4);
+
+void BM_CompareSame(benchmark::State& state) {
+ const int len = state.range(0);
+ std::string x;
+ for (int i = 0; i < len; i++) {
+ x += 'a';
+ }
+ std::string y = x;
+ absl::string_view a = x;
+ absl::string_view b = y;
+
+ for (auto _ : state) {
+ benchmark::DoNotOptimize(a.compare(b));
+ }
+}
+BENCHMARK(BM_CompareSame)->DenseRange(0, 3)->Range(4, 1 << 10);
+
+void BM_find_string_view_len_one(benchmark::State& state) {
+ std::string haystack(state.range(0), '0');
+ absl::string_view s(haystack);
+ for (auto _ : state) {
+ s.find("x"); // not present; length 1
+ }
+}
+BENCHMARK(BM_find_string_view_len_one)->Range(1, 1 << 20);
+
+void BM_find_string_view_len_two(benchmark::State& state) {
+ std::string haystack(state.range(0), '0');
+ absl::string_view s(haystack);
+ for (auto _ : state) {
+ s.find("xx"); // not present; length 2
+ }
+}
+BENCHMARK(BM_find_string_view_len_two)->Range(1, 1 << 20);
+
+void BM_find_one_char(benchmark::State& state) {
+ std::string haystack(state.range(0), '0');
+ absl::string_view s(haystack);
+ for (auto _ : state) {
+ s.find('x'); // not present
+ }
+}
+BENCHMARK(BM_find_one_char)->Range(1, 1 << 20);
+
+void BM_rfind_one_char(benchmark::State& state) {
+ std::string haystack(state.range(0), '0');
+ absl::string_view s(haystack);
+ for (auto _ : state) {
+ s.rfind('x'); // not present
+ }
+}
+BENCHMARK(BM_rfind_one_char)->Range(1, 1 << 20);
+
+void BM_worst_case_find_first_of(benchmark::State& state, int haystack_len) {
+ const int needle_len = state.range(0);
+ std::string needle;
+ for (int i = 0; i < needle_len; ++i) {
+ needle += 'a' + i;
+ }
+ std::string haystack(haystack_len, '0'); // 1000 zeros.
+
+ absl::string_view s(haystack);
+ for (auto _ : state) {
+ s.find_first_of(needle);
+ }
+}
+
+void BM_find_first_of_short(benchmark::State& state) {
+ BM_worst_case_find_first_of(state, 10);
+}
+
+void BM_find_first_of_medium(benchmark::State& state) {
+ BM_worst_case_find_first_of(state, 100);
+}
+
+void BM_find_first_of_long(benchmark::State& state) {
+ BM_worst_case_find_first_of(state, 1000);
+}
+
+BENCHMARK(BM_find_first_of_short)->DenseRange(0, 4)->Arg(8)->Arg(16)->Arg(32);
+BENCHMARK(BM_find_first_of_medium)->DenseRange(0, 4)->Arg(8)->Arg(16)->Arg(32);
+BENCHMARK(BM_find_first_of_long)->DenseRange(0, 4)->Arg(8)->Arg(16)->Arg(32);
+
+struct EasyMap : public std::map<absl::string_view, uint64_t> {
+ explicit EasyMap(size_t) {}
+};
+
+// This templated benchmark helper function is intended to stress operator== or
+// operator< in a realistic test. It surely isn't entirely realistic, but it's
+// a start. The test creates a map of type Map, a template arg, and populates
+// it with table_size key/value pairs. Each key has WordsPerKey words. After
+// creating the map, a number of lookups are done in random order. Some keys
+// are used much more frequently than others in this phase of the test.
+template <typename Map, int WordsPerKey>
+void StringViewMapBenchmark(benchmark::State& state) {
+ const int table_size = state.range(0);
+ const double kFractionOfKeysThatAreHot = 0.2;
+ const int kNumLookupsOfHotKeys = 20;
+ const int kNumLookupsOfColdKeys = 1;
+ const char* words[] = {"the", "quick", "brown", "fox", "jumped",
+ "over", "the", "lazy", "dog", "and",
+ "found", "a", "large", "mushroom", "and",
+ "a", "couple", "crickets", "eating", "pie"};
+ // Create some keys that consist of words in random order.
+ std::random_device r;
+ std::seed_seq seed({r(), r(), r(), r(), r(), r(), r(), r()});
+ std::mt19937 rng(seed);
+ std::vector<std::string> keys(table_size);
+ std::vector<int> all_indices;
+ const int kBlockSize = 1 << 12;
+ std::unordered_set<std::string> t(kBlockSize);
+ std::uniform_int_distribution<int> uniform(0, ABSL_ARRAYSIZE(words) - 1);
+ for (int i = 0; i < table_size; i++) {
+ all_indices.push_back(i);
+ do {
+ keys[i].clear();
+ for (int j = 0; j < WordsPerKey; j++) {
+ absl::StrAppend(&keys[i], j > 0 ? " " : "", words[uniform(rng)]);
+ }
+ } while (!t.insert(keys[i]).second);
+ }
+
+ // Create a list of strings to lookup: a permutation of the array of
+ // keys we just created, with repeats. "Hot" keys get repeated more.
+ std::shuffle(all_indices.begin(), all_indices.end(), rng);
+ const int num_hot = table_size * kFractionOfKeysThatAreHot;
+ const int num_cold = table_size - num_hot;
+ std::vector<int> hot_indices(all_indices.begin(),
+ all_indices.begin() + num_hot);
+ std::vector<int> indices;
+ for (int i = 0; i < kNumLookupsOfColdKeys; i++) {
+ indices.insert(indices.end(), all_indices.begin(), all_indices.end());
+ }
+ for (int i = 0; i < kNumLookupsOfHotKeys - kNumLookupsOfColdKeys; i++) {
+ indices.insert(indices.end(), hot_indices.begin(), hot_indices.end());
+ }
+ std::shuffle(indices.begin(), indices.end(), rng);
+ ABSL_RAW_CHECK(
+ num_cold * kNumLookupsOfColdKeys + num_hot * kNumLookupsOfHotKeys ==
+ indices.size(),
+ "");
+ // After constructing the array we probe it with absl::string_views built from
+ // test_strings. This means operator== won't see equal pointers, so
+ // it'll have to check for equal lengths and equal characters.
+ std::vector<std::string> test_strings(indices.size());
+ for (int i = 0; i < indices.size(); i++) {
+ test_strings[i] = keys[indices[i]];
+ }
+
+ // Run the benchmark. It includes map construction but is mostly
+ // map lookups.
+ for (auto _ : state) {
+ Map h(table_size);
+ for (int i = 0; i < table_size; i++) {
+ h[keys[i]] = i * 2;
+ }
+ ABSL_RAW_CHECK(h.size() == table_size, "");
+ uint64_t sum = 0;
+ for (int i = 0; i < indices.size(); i++) {
+ sum += h[test_strings[i]];
+ }
+ benchmark::DoNotOptimize(sum);
+ }
+}
+
+void BM_StdMap_4(benchmark::State& state) {
+ StringViewMapBenchmark<EasyMap, 4>(state);
+}
+BENCHMARK(BM_StdMap_4)->Range(1 << 10, 1 << 16);
+
+void BM_StdMap_8(benchmark::State& state) {
+ StringViewMapBenchmark<EasyMap, 8>(state);
+}
+BENCHMARK(BM_StdMap_8)->Range(1 << 10, 1 << 16);
+
+void BM_CopyToStringNative(benchmark::State& state) {
+ std::string src(state.range(0), 'x');
+ absl::string_view sv(src);
+ std::string dst;
+ for (auto _ : state) {
+ dst.assign(sv.begin(), sv.end());
+ }
+}
+BENCHMARK(BM_CopyToStringNative)->Range(1 << 3, 1 << 12);
+
+void BM_AppendToStringNative(benchmark::State& state) {
+ std::string src(state.range(0), 'x');
+ absl::string_view sv(src);
+ std::string dst;
+ for (auto _ : state) {
+ dst.clear();
+ dst.insert(dst.end(), sv.begin(), sv.end());
+ }
+}
+BENCHMARK(BM_AppendToStringNative)->Range(1 << 3, 1 << 12);
+
+} // namespace
+
+BENCHMARK_MAIN();
diff --git a/absl/synchronization/mutex.h b/absl/synchronization/mutex.h
index 368684bf..840b9d6b 100644
--- a/absl/synchronization/mutex.h
+++ b/absl/synchronization/mutex.h
@@ -854,7 +854,7 @@ class SCOPED_LOCKABLE MutexLockMaybe {
MutexLockMaybe& operator=(MutexLockMaybe&&) = delete;
};
-// ReleaseableMutexLock
+// ReleasableMutexLock
//
// ReleasableMutexLock is like MutexLock, but permits `Release()` of its
// mutex before destruction. `Release()` may be called at most once.
generated by cgit v1.2.3 (git 2.39.1) at 2024-11-28 13:53:03 +0000