83 lines
3.1 KiB
C++
83 lines
3.1 KiB
C++
/*
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* Copyright (C) 2022 The Android Open Source Project
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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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* http://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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#pragma once
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#include <array>
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#include <ostream>
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#include "IFilesystem.h"
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#include "ITimeSource.h"
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#include "Model.h"
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#include "RealFilesystem.h"
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#include "TimeSource.h"
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namespace aidl {
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namespace google {
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namespace hardware {
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namespace power {
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namespace impl {
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namespace pixel {
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// Kernel <-> Userspace ABI for CPU features. See kernel/sched/acpu.c.
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// Contains CPU statistics for a single CPU. The kernel reports an `acpu_stats` struct for each CPU
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// on the system.
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struct acpu_stats {
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// Sum of the CPU frequencies that the CPU used, multiplied by how much time was spent in each
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// frequency. Measured in ns*KHz. E.g.:
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// 10ns at 100MHz, 2ns at 50MHz = 10*100,000 + 2*50,000 = 1,100,000
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// This is used to calculate the average frequency the CPU was running at between two times:
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// (new.weighted_sum_freq - old.weighted_sum_freq) / elapsed_time_ns
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uint64_t weighted_sum_freq;
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// The total time (in nanoseconds) that the CPU was idle.
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// This is ued to calculate the percent of time the CPU was idle between two times:
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// (new.total_idle_time_ns - old.total_idle_time_ns) / elapsed_time_ns
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uint64_t total_idle_time_ns;
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};
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class KernelCpuFeatureReader {
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public:
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KernelCpuFeatureReader()
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: mFilesystem(std::make_unique<RealFilesystem>()),
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mTimeSource(std::make_unique<TimeSource>()) {}
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KernelCpuFeatureReader(std::unique_ptr<IFilesystem> filesystem,
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std::unique_ptr<ITimeSource> timeSource)
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: mFilesystem(std::move(filesystem)), mTimeSource(std::move(timeSource)) {}
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bool Init();
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bool GetRecentCpuFeatures(std::array<double, NUM_CPU_POLICIES> *cpuPolicyAverageFrequencyHz,
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std::array<double, NUM_CPU_CORES> *cpuCoreIdleTimesPercentage);
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void DumpToStream(std::ostream &stream) const;
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private:
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const std::unique_ptr<IFilesystem> mFilesystem;
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const std::unique_ptr<ITimeSource> mTimeSource;
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// We only open the stats file once and reuse the file descriptor. We find this reduces
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// ReadStats runtime by 2x.
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std::unique_ptr<std::istream> mStatsFile;
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std::array<acpu_stats, NUM_CPU_CORES> mPreviousStats;
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std::chrono::nanoseconds mPreviousReadTime;
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bool OpenStatsFile(std::unique_ptr<std::istream> *file);
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bool ReadStats(std::array<acpu_stats, NUM_CPU_CORES> *stats,
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std::chrono::nanoseconds *readTime);
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};
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} // namespace pixel
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} // namespace impl
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} // namespace power
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} // namespace hardware
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} // namespace google
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} // namespace aidl
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