1 /*
2 * Copyright (C) 2021 The Android Open Source Project
3 *
4 * Licensed under the Apache License, Version 2.0 (the "License");
5 * you may not use this file except in compliance with the License.
6 * You may obtain a copy of the License at
7 *
8 * http://www.apache.org/licenses/LICENSE-2.0
9 *
10 * Unless required by applicable law or agreed to in writing, software
11 * distributed under the License is distributed on an "AS IS" BASIS,
12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13 * See the License for the specific language governing permissions and
14 * limitations under the License.
15 */
16
17 #define LOG_TAG "powerhal-adaptivecpu"
18 #define ATRACE_TAG (ATRACE_TAG_POWER | ATRACE_TAG_HAL)
19
20 #include "CpuFrequencyReader.h"
21
22 #include <android-base/logging.h>
23 #include <inttypes.h>
24 #include <utils/Trace.h>
25
26 #include <fstream>
27 #include <memory>
28 #include <sstream>
29
30 using std::chrono_literals::operator""ms;
31
32 constexpr std::string_view kCpuPolicyDirectory("/sys/devices/system/cpu/cpufreq");
33
34 namespace aidl {
35 namespace google {
36 namespace hardware {
37 namespace power {
38 namespace impl {
39 namespace pixel {
40
Init()41 bool CpuFrequencyReader::Init() {
42 ATRACE_CALL();
43 mCpuPolicyIds.clear();
44 if (!ReadCpuPolicyIds(&mCpuPolicyIds)) {
45 return false;
46 }
47 mPreviousCpuPolicyFrequencies.clear();
48 return ReadCpuPolicyFrequencies(&mPreviousCpuPolicyFrequencies);
49 }
50
GetRecentCpuPolicyFrequencies(std::vector<CpuPolicyAverageFrequency> * result)51 bool CpuFrequencyReader::GetRecentCpuPolicyFrequencies(
52 std::vector<CpuPolicyAverageFrequency> *result) {
53 ATRACE_CALL();
54 std::map<uint32_t, std::map<uint64_t, std::chrono::milliseconds>> cpuPolicyFrequencies;
55 if (!ReadCpuPolicyFrequencies(&cpuPolicyFrequencies)) {
56 return false;
57 }
58 for (const auto &[policyId, cpuFrequencies] : cpuPolicyFrequencies) {
59 const auto &previousCpuFrequencies = mPreviousCpuPolicyFrequencies.find(policyId);
60 if (previousCpuFrequencies == mPreviousCpuPolicyFrequencies.end()) {
61 LOG(ERROR) << "Couldn't find policy " << policyId << " in previous frequencies";
62 return false;
63 }
64 uint64_t weightedFrequenciesSumHz = 0;
65 std::chrono::milliseconds timeSum = 0ms;
66 for (const auto &[frequencyHz, time] : cpuFrequencies) {
67 const auto &previousCpuFrequency = previousCpuFrequencies->second.find(frequencyHz);
68 if (previousCpuFrequency == previousCpuFrequencies->second.end()) {
69 LOG(ERROR) << "Couldn't find frequency " << frequencyHz
70 << " in previous frequencies";
71 return false;
72 }
73 const std::chrono::milliseconds recentTime = time - previousCpuFrequency->second;
74 weightedFrequenciesSumHz += frequencyHz * recentTime.count();
75 timeSum += recentTime;
76 }
77 const uint64_t averageFrequencyHz =
78 timeSum != 0ms ? weightedFrequenciesSumHz / timeSum.count() : 0;
79 result->push_back({.policyId = policyId, .averageFrequencyHz = averageFrequencyHz});
80 }
81 mPreviousCpuPolicyFrequencies = cpuPolicyFrequencies;
82 return true;
83 }
84
85 std::map<uint32_t, std::map<uint64_t, std::chrono::milliseconds>>
GetPreviousCpuPolicyFrequencies() const86 CpuFrequencyReader::GetPreviousCpuPolicyFrequencies() const {
87 return mPreviousCpuPolicyFrequencies;
88 }
89
ReadCpuPolicyFrequencies(std::map<uint32_t,std::map<uint64_t,std::chrono::milliseconds>> * result)90 bool CpuFrequencyReader::ReadCpuPolicyFrequencies(
91 std::map<uint32_t, std::map<uint64_t, std::chrono::milliseconds>> *result) {
92 ATRACE_CALL();
93 for (const uint32_t cpuPolicyId : mCpuPolicyIds) {
94 std::stringstream timeInStatePath;
95 timeInStatePath << "/sys/devices/system/cpu/cpufreq/policy" << cpuPolicyId
96 << "/stats/time_in_state";
97 std::unique_ptr<std::istream> timeInStateFile;
98 if (!mFilesystem->ReadFileStream(timeInStatePath.str(), &timeInStateFile)) {
99 return false;
100 }
101
102 std::map<uint64_t, std::chrono::milliseconds> cpuFrequencies;
103 std::string timeInStateLine;
104 while (std::getline(*timeInStateFile, timeInStateLine)) {
105 // Time format in time_in_state is 10s of milliseconds:
106 // https://www.kernel.org/doc/Documentation/cpu-freq/cpufreq-stats.txt
107 uint64_t frequencyHz, time10Ms;
108 if (std::sscanf(timeInStateLine.c_str(), "%" PRIu64 " %" PRIu64 "\n", &frequencyHz,
109 &time10Ms) != 2) {
110 LOG(ERROR) << "Failed to parse time_in_state line: " << timeInStateLine;
111 return false;
112 }
113 cpuFrequencies[frequencyHz] = time10Ms * 10ms;
114 }
115 if (cpuFrequencies.size() > 500) {
116 LOG(ERROR) << "Found " << cpuFrequencies.size() << " frequencies for policy "
117 << cpuPolicyId << ", aborting";
118 return false;
119 }
120 (*result)[cpuPolicyId] = cpuFrequencies;
121 }
122 return true;
123 }
124
ReadCpuPolicyIds(std::vector<uint32_t> * result) const125 bool CpuFrequencyReader::ReadCpuPolicyIds(std::vector<uint32_t> *result) const {
126 ATRACE_CALL();
127 std::vector<std::string> entries;
128 if (!mFilesystem->ListDirectory(kCpuPolicyDirectory.data(), &entries)) {
129 return false;
130 }
131 for (const auto &entry : entries) {
132 uint32_t cpuPolicyId;
133 if (!sscanf(entry.c_str(), "policy%d", &cpuPolicyId)) {
134 continue;
135 }
136 result->push_back(cpuPolicyId);
137 }
138 // Sort the list, so that getRecentCpuPolicyFrequencies always returns frequencies sorted by
139 // policy ID.
140 std::sort(result->begin(), result->end());
141 return true;
142 }
143
144 } // namespace pixel
145 } // namespace impl
146 } // namespace power
147 } // namespace hardware
148 } // namespace google
149 } // namespace aidl
150