1 /*
2 * Copyright (C) 2020 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 #include "src/traced/probes/common/cpu_freq_info.h"
18
19 #include <unistd.h>
20
21 #include <set>
22
23 #include "perfetto/ext/base/file_utils.h"
24 #include "perfetto/ext/base/string_splitter.h"
25 #include "perfetto/ext/base/string_utils.h"
26
27 namespace perfetto {
28
29 namespace {
30
31 using CpuAndFreq = std::pair</* cpu */ uint32_t, /* freq */ uint32_t>;
32
33 // Reads space-separated CPU frequencies from a sysfs file.
ReadAndAppendFreqs(std::set<CpuAndFreq> * freqs,uint32_t cpu_index,const std::string & sys_cpu_freqs)34 void ReadAndAppendFreqs(std::set<CpuAndFreq>* freqs,
35 uint32_t cpu_index,
36 const std::string& sys_cpu_freqs) {
37 base::StringSplitter entries(sys_cpu_freqs, ' ');
38 while (entries.Next()) {
39 auto freq = base::StringToUInt32(entries.cur_token());
40 if (freq.has_value())
41 freqs->insert({cpu_index, freq.value()});
42 }
43 }
44
45 } // namespace
46
CpuFreqInfo(std::string sysfs_cpu_path)47 CpuFreqInfo::CpuFreqInfo(std::string sysfs_cpu_path)
48 : sysfs_cpu_path_{sysfs_cpu_path} {
49 base::ScopedDir cpu_dir(opendir(sysfs_cpu_path_.c_str()));
50 if (!cpu_dir) {
51 PERFETTO_PLOG("Failed to opendir(%s)", sysfs_cpu_path_.c_str());
52 return;
53 }
54 // Accumulate cpu and freqs into a set to ensure stable order.
55 std::set<CpuAndFreq> freqs;
56 while (struct dirent* dir_ent = readdir(*cpu_dir)) {
57 if (dir_ent->d_type != DT_DIR)
58 continue;
59 std::string dir_name(dir_ent->d_name);
60 if (!base::StartsWith(dir_name, "cpu"))
61 continue;
62 auto maybe_cpu_index =
63 base::StringToUInt32(base::StripPrefix(dir_name, "cpu"));
64 // There are some directories (cpufreq, cpuidle) which should be skipped.
65 if (!maybe_cpu_index.has_value())
66 continue;
67 uint32_t cpu_index = maybe_cpu_index.value();
68 ReadAndAppendFreqs(
69 &freqs, cpu_index,
70 ReadFile(sysfs_cpu_path_ + "/cpu" + std::to_string(cpu_index) +
71 "/cpufreq/scaling_available_frequencies"));
72 ReadAndAppendFreqs(
73 &freqs, cpu_index,
74 ReadFile(sysfs_cpu_path_ + "/cpu" + std::to_string(cpu_index) +
75 "/cpufreq/scaling_boost_frequencies"));
76 }
77
78 // Build index with guards.
79 uint32_t last_cpu = 0;
80 uint32_t index = 0;
81 frequencies_index_.push_back(0);
82 for (const auto& cpu_freq : freqs) {
83 frequencies_.push_back(cpu_freq.second);
84 if (cpu_freq.first != last_cpu)
85 frequencies_index_.push_back(index);
86 last_cpu = cpu_freq.first;
87 index++;
88 }
89 frequencies_.push_back(0);
90 frequencies_index_.push_back(index);
91 }
92
93 CpuFreqInfo::~CpuFreqInfo() = default;
94
GetFreqs(uint32_t cpu)95 CpuFreqInfo::Range CpuFreqInfo::GetFreqs(uint32_t cpu) {
96 if (cpu >= frequencies_index_.size() - 1) {
97 PERFETTO_DLOG("No frequencies for cpu%" PRIu32, cpu);
98 const uint32_t* end = frequencies_.data() + frequencies_.size();
99 return {end, end};
100 }
101 auto* start = &frequencies_[frequencies_index_[cpu]];
102 auto* end = &frequencies_[frequencies_index_[cpu + 1]];
103 return {start, end};
104 }
105
GetCpuFreqIndex(uint32_t cpu,uint32_t freq)106 uint32_t CpuFreqInfo::GetCpuFreqIndex(uint32_t cpu, uint32_t freq) {
107 auto range = GetFreqs(cpu);
108 uint32_t index = 0;
109 for (const uint32_t* it = range.first; it != range.second; it++, index++) {
110 if (*it == freq) {
111 return static_cast<uint32_t>(frequencies_index_[cpu]) + index + 1;
112 }
113 }
114 return 0;
115 }
116
ReadFile(std::string path)117 std::string CpuFreqInfo::ReadFile(std::string path) {
118 std::string contents;
119 if (!base::ReadFile(path, &contents))
120 return "";
121 return contents;
122 }
123
ReadCpuCurrFreq()124 const std::vector<uint32_t>& CpuFreqInfo::ReadCpuCurrFreq() {
125 // Check if capacity of cpu_curr_freq_ is enough for all CPUs
126 auto num_cpus = static_cast<size_t>(sysconf(_SC_NPROCESSORS_CONF));
127 if (cpu_curr_freq_.size() < num_cpus)
128 cpu_curr_freq_.resize(num_cpus);
129
130 for (uint32_t i = 0; i < cpu_curr_freq_.size(); i++) {
131 // Read CPU current frequency. Set 0 for offline/disabled cpus.
132 std::string buf(ReadFile(sysfs_cpu_path_ + "/cpu" + std::to_string(i) +
133 "/cpufreq/scaling_cur_freq"));
134 if (buf.empty()) {
135 cpu_curr_freq_[i] = 0;
136 continue;
137 }
138 auto freq = base::StringToUInt32(base::StripSuffix(buf, "\n"));
139 if (!freq.has_value()) {
140 cpu_curr_freq_[i] = 0;
141 continue;
142 }
143 cpu_curr_freq_[i] = freq.value();
144 }
145 return cpu_curr_freq_;
146 }
147
148 } // namespace perfetto
149