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/*
* Copyright (C) 2021 The Android Open Source Project
*
* 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.
*/
#define LOG_TAG "powerhal-adaptivecpu"
#define ATRACE_TAG (ATRACE_TAG_POWER | ATRACE_TAG_HAL)
#include "CpuFrequencyReader.h"
#include <android-base/logging.h>
#include <inttypes.h>
#include <utils/Trace.h>
#include <fstream>
#include <memory>
#include <sstream>
using std::chrono_literals::operator""ms;
constexpr std::string_view kCpuPolicyDirectory("/sys/devices/system/cpu/cpufreq");
namespace aidl {
namespace google {
namespace hardware {
namespace power {
namespace impl {
namespace pixel {
bool CpuFrequencyReader::Init() {
ATRACE_CALL();
mCpuPolicyIds.clear();
if (!ReadCpuPolicyIds(&mCpuPolicyIds)) {
return false;
}
mPreviousCpuPolicyFrequencies.clear();
return ReadCpuPolicyFrequencies(&mPreviousCpuPolicyFrequencies);
}
bool CpuFrequencyReader::GetRecentCpuPolicyFrequencies(
std::vector<CpuPolicyAverageFrequency> *result) {
ATRACE_CALL();
std::map<uint32_t, std::map<uint64_t, std::chrono::milliseconds>> cpuPolicyFrequencies;
if (!ReadCpuPolicyFrequencies(&cpuPolicyFrequencies)) {
return false;
}
for (const auto &[policyId, cpuFrequencies] : cpuPolicyFrequencies) {
const auto &previousCpuFrequencies = mPreviousCpuPolicyFrequencies.find(policyId);
if (previousCpuFrequencies == mPreviousCpuPolicyFrequencies.end()) {
LOG(ERROR) << "Couldn't find policy " << policyId << " in previous frequencies";
return false;
}
uint64_t weightedFrequenciesSumHz = 0;
std::chrono::milliseconds timeSum = 0ms;
for (const auto &[frequencyHz, time] : cpuFrequencies) {
const auto &previousCpuFrequency = previousCpuFrequencies->second.find(frequencyHz);
if (previousCpuFrequency == previousCpuFrequencies->second.end()) {
LOG(ERROR) << "Couldn't find frequency " << frequencyHz
<< " in previous frequencies";
return false;
}
const std::chrono::milliseconds recentTime = time - previousCpuFrequency->second;
weightedFrequenciesSumHz += frequencyHz * recentTime.count();
timeSum += recentTime;
}
const uint64_t averageFrequencyHz =
timeSum != 0ms ? weightedFrequenciesSumHz / timeSum.count() : 0;
result->push_back({.policyId = policyId, .averageFrequencyHz = averageFrequencyHz});
}
mPreviousCpuPolicyFrequencies = cpuPolicyFrequencies;
return true;
}
std::map<uint32_t, std::map<uint64_t, std::chrono::milliseconds>>
CpuFrequencyReader::GetPreviousCpuPolicyFrequencies() const {
return mPreviousCpuPolicyFrequencies;
}
bool CpuFrequencyReader::ReadCpuPolicyFrequencies(
std::map<uint32_t, std::map<uint64_t, std::chrono::milliseconds>> *result) {
ATRACE_CALL();
for (const uint32_t cpuPolicyId : mCpuPolicyIds) {
std::stringstream timeInStatePath;
timeInStatePath << "/sys/devices/system/cpu/cpufreq/policy" << cpuPolicyId
<< "/stats/time_in_state";
std::unique_ptr<std::istream> timeInStateFile;
if (!mFilesystem->ReadFileStream(timeInStatePath.str(), &timeInStateFile)) {
return false;
}
std::map<uint64_t, std::chrono::milliseconds> cpuFrequencies;
std::string timeInStateLine;
while (std::getline(*timeInStateFile, timeInStateLine)) {
// Time format in time_in_state is 10s of milliseconds:
// https://www.kernel.org/doc/Documentation/cpu-freq/cpufreq-stats.txt
uint64_t frequencyHz, time10Ms;
if (std::sscanf(timeInStateLine.c_str(), "%" PRIu64 " %" PRIu64 "\n", &frequencyHz,
&time10Ms) != 2) {
LOG(ERROR) << "Failed to parse time_in_state line: " << timeInStateLine;
return false;
}
cpuFrequencies[frequencyHz] = time10Ms * 10ms;
}
if (cpuFrequencies.size() > 500) {
LOG(ERROR) << "Found " << cpuFrequencies.size() << " frequencies for policy "
<< cpuPolicyId << ", aborting";
return false;
}
(*result)[cpuPolicyId] = cpuFrequencies;
}
return true;
}
bool CpuFrequencyReader::ReadCpuPolicyIds(std::vector<uint32_t> *result) const {
ATRACE_CALL();
std::vector<std::string> entries;
if (!mFilesystem->ListDirectory(kCpuPolicyDirectory.data(), &entries)) {
return false;
}
for (const auto &entry : entries) {
uint32_t cpuPolicyId;
if (!sscanf(entry.c_str(), "policy%d", &cpuPolicyId)) {
continue;
}
result->push_back(cpuPolicyId);
}
// Sort the list, so that getRecentCpuPolicyFrequencies always returns frequencies sorted by
// policy ID.
std::sort(result->begin(), result->end());
return true;
}
} // namespace pixel
} // namespace impl
} // namespace power
} // namespace hardware
} // namespace google
} // namespace aidl
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