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//
// Copyright 2020 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 <stdint.h>
#include <string>
#include <vector>
#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"
#include "benchmark/benchmark.h"
namespace {
using String = std::string;
using VectorOfStrings = std::vector<std::string>;
using AbslDuration = absl::Duration;
// We do not want to take over marshalling for the types absl::optional<int>,
// absl::optional<std::string> which we do not own. Instead we introduce unique
// "aliases" to these types, which we do.
using AbslOptionalInt = absl::optional<int>;
struct OptionalInt : AbslOptionalInt {
using AbslOptionalInt::AbslOptionalInt;
};
// Next two functions represent Abseil Flags marshalling for OptionalInt.
bool AbslParseFlag(absl::string_view src, OptionalInt* flag,
std::string* error) {
int val;
if (src.empty())
flag->reset();
else if (!absl::ParseFlag(src, &val, error))
return false;
*flag = val;
return true;
}
std::string AbslUnparseFlag(const OptionalInt& flag) {
return !flag ? "" : absl::UnparseFlag(*flag);
}
using AbslOptionalString = absl::optional<std::string>;
struct OptionalString : AbslOptionalString {
using AbslOptionalString::AbslOptionalString;
};
// Next two functions represent Abseil Flags marshalling for OptionalString.
bool AbslParseFlag(absl::string_view src, OptionalString* flag,
std::string* error) {
std::string val;
if (src.empty())
flag->reset();
else if (!absl::ParseFlag(src, &val, error))
return false;
*flag = val;
return true;
}
std::string AbslUnparseFlag(const OptionalString& flag) {
return !flag ? "" : absl::UnparseFlag(*flag);
}
struct UDT {
UDT() = default;
UDT(const UDT&) {}
UDT& operator=(const UDT&) { return *this; }
};
// Next two functions represent Abseil Flags marshalling for UDT.
bool AbslParseFlag(absl::string_view, UDT*, std::string*) { return true; }
std::string AbslUnparseFlag(const UDT&) { return ""; }
} // namespace
#define BENCHMARKED_TYPES(A) \
A(bool) \
A(int16_t) \
A(uint16_t) \
A(int32_t) \
A(uint32_t) \
A(int64_t) \
A(uint64_t) \
A(double) \
A(float) \
A(String) \
A(VectorOfStrings) \
A(OptionalInt) \
A(OptionalString) \
A(AbslDuration) \
A(UDT)
#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 {
#define BM_GetFlag(T) \
void BM_GetFlag_##T(benchmark::State& state) { \
for (auto _ : state) { \
benchmark::DoNotOptimize(absl::GetFlag(FLAGS_##T##_flag)); \
} \
} \
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) \
T AbslInvokeGetFlag##T() { return absl::GetFlag(FLAGS_##T##_flag); } \
int odr##T = (benchmark::DoNotOptimize(AbslInvokeGetFlag##T), 1);
BENCHMARKED_TYPES(InvokeGetFlag)
// To veiw disassembly use: gdb ${BINARY} -batch -ex "disassemble /s $FUNC"
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