chromium/third_party/google_benchmark/src/src/perf_counters.h

// Copyright 2021 Google Inc. All rights reserved.
//
// 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.

#ifndef BENCHMARK_PERF_COUNTERS_H
#define BENCHMARK_PERF_COUNTERS_H

#include <array>
#include <cstdint>
#include <cstring>
#include <memory>
#include <vector>

#include "benchmark/benchmark.h"
#include "check.h"
#include "log.h"
#include "mutex.h"

#ifndef BENCHMARK_OS_WINDOWS
#include <unistd.h>
#endif

#if defined(_MSC_VER)
#pragma warning(push)
// C4251: <symbol> needs to have dll-interface to be used by clients of class
#pragma warning(disable : 4251)
#endif

namespace benchmark {
namespace internal {

// Typically, we can only read a small number of counters. There is also a
// padding preceding counter values, when reading multiple counters with one
// syscall (which is desirable). PerfCounterValues abstracts these details.
// The implementation ensures the storage is inlined, and allows 0-based
// indexing into the counter values.
// The object is used in conjunction with a PerfCounters object, by passing it
// to Snapshot(). The Read() method relocates individual reads, discarding
// the initial padding from each group leader in the values buffer such that
// all user accesses through the [] operator are correct.
class BENCHMARK_EXPORT PerfCounterValues { … };

// Collect PMU counters. The object, once constructed, is ready to be used by
// calling read(). PMU counter collection is enabled from the time create() is
// called, to obtain the object, until the object's destructor is called.
class BENCHMARK_EXPORT PerfCounters final { … };

// Typical usage of the above primitives.
class BENCHMARK_EXPORT PerfCountersMeasurement final { … };

}  // namespace internal
}  // namespace benchmark

#if defined(_MSC_VER)
#pragma warning(pop)
#endif

#endif  // BENCHMARK_PERF_COUNTERS_H