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Diffstat (limited to 'media/highway/src/hwy/nanobenchmark_test.cc')
-rw-r--r-- | media/highway/src/hwy/nanobenchmark_test.cc | 91 |
1 files changed, 91 insertions, 0 deletions
diff --git a/media/highway/src/hwy/nanobenchmark_test.cc b/media/highway/src/hwy/nanobenchmark_test.cc new file mode 100644 index 0000000000..5fc011aea4 --- /dev/null +++ b/media/highway/src/hwy/nanobenchmark_test.cc @@ -0,0 +1,91 @@ +// Copyright 2019 Google LLC +// SPDX-License-Identifier: Apache-2.0 +// +// 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 "hwy/nanobenchmark.h" + +#include <inttypes.h> +#include <stdint.h> +#include <stdio.h> + +#include <random> + +#include "hwy/tests/test_util-inl.h" + +namespace hwy { +namespace { + +// Governs duration of test; avoid timeout in debug builds. +#if HWY_IS_DEBUG_BUILD +constexpr size_t kMaxEvals = 3; +#else +constexpr size_t kMaxEvals = 4; +#endif + +FuncOutput Div(const void*, FuncInput in) { + // Here we're measuring the throughput because benchmark invocations are + // independent. Any dividend will do; the divisor is nonzero. + return 0xFFFFF / in; +} + +template <size_t N> +void MeasureDiv(const FuncInput (&inputs)[N]) { + printf("Measuring integer division (output on final two lines)\n"); + Result results[N]; + Params params; + params.max_evals = kMaxEvals; + const size_t num_results = Measure(&Div, nullptr, inputs, N, results, params); + for (size_t i = 0; i < num_results; ++i) { + printf("%5" PRIu64 ": %6.2f ticks; MAD=%4.2f%%\n", + static_cast<uint64_t>(results[i].input), results[i].ticks, + results[i].variability * 100.0); + } +} + +std::mt19937 rng; + +// A function whose runtime depends on rng. +FuncOutput Random(const void* /*arg*/, FuncInput in) { + const size_t r = rng() & 0xF; + uint32_t ret = in; + for (size_t i = 0; i < r; ++i) { + ret /= ((rng() & 1) + 2); + } + return ret; +} + +// Ensure the measured variability is high. +template <size_t N> +void MeasureRandom(const FuncInput (&inputs)[N]) { + Result results[N]; + Params p; + p.max_evals = kMaxEvals; + p.verbose = false; + const size_t num_results = Measure(&Random, nullptr, inputs, N, results, p); + for (size_t i = 0; i < num_results; ++i) { + NANOBENCHMARK_CHECK(results[i].variability > 1E-3); + } +} + +TEST(NanobenchmarkTest, RunAll) { + const int unpredictable = Unpredictable1(); // == 1, unknown to compiler. + static const FuncInput inputs[] = {static_cast<FuncInput>(unpredictable) + 2, + static_cast<FuncInput>(unpredictable + 9)}; + + MeasureDiv(inputs); + MeasureRandom(inputs); +} + +} // namespace +} // namespace hwy |