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// 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
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