123 lines
4.1 KiB
C++
123 lines
4.1 KiB
C++
// Copyright 2018 The Abseil Authors.
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//
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// Licensed under the Apache License, Version 2.0 (the "License");
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// you may not use this file except in compliance with the License.
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// You may obtain a copy of the License at
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//
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// https://www.apache.org/licenses/LICENSE-2.0
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//
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// Unless required by applicable law or agreed to in writing, software
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// distributed under the License is distributed on an "AS IS" BASIS,
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// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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// See the License for the specific language governing permissions and
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// limitations under the License.
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//
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// Every benchmark should have the same performance as the corresponding
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// headroom benchmark.
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#include "absl/base/internal/raw_logging.h"
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#include "absl/container/internal/layout.h"
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#include "benchmark/benchmark.h"
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namespace absl {
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ABSL_NAMESPACE_BEGIN
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namespace container_internal {
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namespace {
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using ::benchmark::DoNotOptimize;
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using Int128 = int64_t[2];
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// This benchmark provides the upper bound on performance for BM_OffsetConstant.
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template <size_t Offset, class... Ts>
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void BM_OffsetConstantHeadroom(benchmark::State& state) {
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for (auto _ : state) {
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DoNotOptimize(Offset);
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}
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}
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template <size_t Offset, class... Ts>
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void BM_OffsetConstant(benchmark::State& state) {
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using L = Layout<Ts...>;
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ABSL_RAW_CHECK(L::Partial(3, 5, 7).template Offset<3>() == Offset,
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"Invalid offset");
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for (auto _ : state) {
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DoNotOptimize(L::Partial(3, 5, 7).template Offset<3>());
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}
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}
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template <class... Ts>
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size_t VariableOffset(size_t n, size_t m, size_t k);
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template <>
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size_t VariableOffset<int8_t, int16_t, int32_t, Int128>(size_t n, size_t m,
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size_t k) {
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auto Align = [](size_t n, size_t m) { return (n + m - 1) & ~(m - 1); };
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return Align(Align(Align(n * 1, 2) + m * 2, 4) + k * 4, 8);
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}
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template <>
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size_t VariableOffset<Int128, int32_t, int16_t, int8_t>(size_t n, size_t m,
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size_t k) {
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// No alignment is necessary.
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return n * 16 + m * 4 + k * 2;
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}
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// This benchmark provides the upper bound on performance for BM_OffsetVariable.
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template <size_t Offset, class... Ts>
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void BM_OffsetVariableHeadroom(benchmark::State& state) {
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size_t n = 3;
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size_t m = 5;
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size_t k = 7;
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ABSL_RAW_CHECK(VariableOffset<Ts...>(n, m, k) == Offset, "Invalid offset");
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for (auto _ : state) {
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DoNotOptimize(n);
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DoNotOptimize(m);
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DoNotOptimize(k);
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DoNotOptimize(VariableOffset<Ts...>(n, m, k));
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}
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}
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template <size_t Offset, class... Ts>
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void BM_OffsetVariable(benchmark::State& state) {
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using L = Layout<Ts...>;
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size_t n = 3;
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size_t m = 5;
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size_t k = 7;
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ABSL_RAW_CHECK(L::Partial(n, m, k).template Offset<3>() == Offset,
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"Inavlid offset");
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for (auto _ : state) {
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DoNotOptimize(n);
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DoNotOptimize(m);
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DoNotOptimize(k);
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DoNotOptimize(L::Partial(n, m, k).template Offset<3>());
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}
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}
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// Run all benchmarks in two modes:
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//
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// Layout with padding: int8_t[3], int16_t[5], int32_t[7], Int128[?].
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// Layout without padding: Int128[3], int32_t[5], int16_t[7], int8_t[?].
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#define OFFSET_BENCHMARK(NAME, OFFSET, T1, T2, T3, T4) \
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auto& NAME##_##OFFSET##_##T1##_##T2##_##T3##_##T4 = \
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NAME<OFFSET, T1, T2, T3, T4>; \
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BENCHMARK(NAME##_##OFFSET##_##T1##_##T2##_##T3##_##T4)
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OFFSET_BENCHMARK(BM_OffsetConstantHeadroom, 48, int8_t, int16_t, int32_t,
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Int128);
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OFFSET_BENCHMARK(BM_OffsetConstant, 48, int8_t, int16_t, int32_t, Int128);
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OFFSET_BENCHMARK(BM_OffsetConstantHeadroom, 82, Int128, int32_t, int16_t,
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int8_t);
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OFFSET_BENCHMARK(BM_OffsetConstant, 82, Int128, int32_t, int16_t, int8_t);
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OFFSET_BENCHMARK(BM_OffsetVariableHeadroom, 48, int8_t, int16_t, int32_t,
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Int128);
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OFFSET_BENCHMARK(BM_OffsetVariable, 48, int8_t, int16_t, int32_t, Int128);
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OFFSET_BENCHMARK(BM_OffsetVariableHeadroom, 82, Int128, int32_t, int16_t,
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int8_t);
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OFFSET_BENCHMARK(BM_OffsetVariable, 82, Int128, int32_t, int16_t, int8_t);
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} // namespace
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} // namespace container_internal
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ABSL_NAMESPACE_END
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} // namespace absl
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