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Diffstat (limited to 'absl/container/internal/layout_benchmark.cc')
-rw-r--r-- | absl/container/internal/layout_benchmark.cc | 122 |
1 files changed, 122 insertions, 0 deletions
diff --git a/absl/container/internal/layout_benchmark.cc b/absl/container/internal/layout_benchmark.cc new file mode 100644 index 00000000..d8636e8d --- /dev/null +++ b/absl/container/internal/layout_benchmark.cc @@ -0,0 +1,122 @@ +// 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, + "Inavlid 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 |