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// 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.
//
// Every benchmark should have the same performance as the corresponding
// headroom benchmark.
#include "absl/base/internal/raw_logging.h"
#include "absl/container/internal/layout.h"
#include "benchmark/benchmark.h"
namespace absl {
ABSL_NAMESPACE_BEGIN
namespace container_internal {
namespace {
using ::benchmark::DoNotOptimize;
using Int128 = int64_t[2];
// This benchmark provides the upper bound on performance for BM_OffsetConstant.
template <size_t Offset, class... Ts>
void BM_OffsetConstantHeadroom(benchmark::State& state) {
for (auto _ : state) {
DoNotOptimize(Offset);
}
}
template <size_t Offset, class... Ts>
void BM_OffsetConstant(benchmark::State& state) {
using L = Layout<Ts...>;
ABSL_RAW_CHECK(L::Partial(3, 5, 7).template Offset<3>() == Offset,
"Invalid offset");
for (auto _ : state) {
DoNotOptimize(L::Partial(3, 5, 7).template Offset<3>());
}
}
template <class... Ts>
size_t VariableOffset(size_t n, size_t m, size_t k);
template <>
size_t VariableOffset<int8_t, int16_t, int32_t, Int128>(size_t n, size_t m,
size_t k) {
auto Align = [](size_t n, size_t m) { return (n + m - 1) & ~(m - 1); };
return Align(Align(Align(n * 1, 2) + m * 2, 4) + k * 4, 8);
}
template <>
size_t VariableOffset<Int128, int32_t, int16_t, int8_t>(size_t n, size_t m,
size_t k) {
// No alignment is necessary.
return n * 16 + m * 4 + k * 2;
}
// This benchmark provides the upper bound on performance for BM_OffsetVariable.
template <size_t Offset, class... Ts>
void BM_OffsetVariableHeadroom(benchmark::State& state) {
size_t n = 3;
size_t m = 5;
size_t k = 7;
ABSL_RAW_CHECK(VariableOffset<Ts...>(n, m, k) == Offset, "Invalid offset");
for (auto _ : state) {
DoNotOptimize(n);
DoNotOptimize(m);
DoNotOptimize(k);
DoNotOptimize(VariableOffset<Ts...>(n, m, k));
}
}
template <size_t Offset, class... Ts>
void BM_OffsetVariable(benchmark::State& state) {
using L = Layout<Ts...>;
size_t n = 3;
size_t m = 5;
size_t k = 7;
ABSL_RAW_CHECK(L::Partial(n, m, k).template Offset<3>() == Offset,
"Invalid offset");
for (auto _ : state) {
DoNotOptimize(n);
DoNotOptimize(m);
DoNotOptimize(k);
DoNotOptimize(L::Partial(n, m, k).template Offset<3>());
}
}
// Run all benchmarks in two modes:
//
// Layout with padding: int8_t[3], int16_t[5], int32_t[7], Int128[?].
// Layout without padding: Int128[3], int32_t[5], int16_t[7], int8_t[?].
#define OFFSET_BENCHMARK(NAME, OFFSET, T1, T2, T3, T4) \
auto& NAME##_##OFFSET##_##T1##_##T2##_##T3##_##T4 = \
NAME<OFFSET, T1, T2, T3, T4>; \
BENCHMARK(NAME##_##OFFSET##_##T1##_##T2##_##T3##_##T4)
OFFSET_BENCHMARK(BM_OffsetConstantHeadroom, 48, int8_t, int16_t, int32_t,
Int128);
OFFSET_BENCHMARK(BM_OffsetConstant, 48, int8_t, int16_t, int32_t, Int128);
OFFSET_BENCHMARK(BM_OffsetConstantHeadroom, 82, Int128, int32_t, int16_t,
int8_t);
OFFSET_BENCHMARK(BM_OffsetConstant, 82, Int128, int32_t, int16_t, int8_t);
OFFSET_BENCHMARK(BM_OffsetVariableHeadroom, 48, int8_t, int16_t, int32_t,
Int128);
OFFSET_BENCHMARK(BM_OffsetVariable, 48, int8_t, int16_t, int32_t, Int128);
OFFSET_BENCHMARK(BM_OffsetVariableHeadroom, 82, Int128, int32_t, int16_t,
int8_t);
OFFSET_BENCHMARK(BM_OffsetVariable, 82, Int128, int32_t, int16_t, int8_t);
} // namespace
} // namespace container_internal
ABSL_NAMESPACE_END
} // namespace absl
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