Get the maximim number of CPUs in the system by parsing /sys/devices/system/cpu/present * * @return int Maximum number of CPUs */
| 246 | * @return int Maximum number of CPUs |
| 247 | */ |
| 248 | int get_max_cpus() |
| 249 | { |
| 250 | int max_cpus = 1; |
| 251 | std::ifstream CPUspresent; |
| 252 | CPUspresent.open("/sys/devices/system/cpu/present", std::ios::in); |
| 253 | bool success = false; |
| 254 | |
| 255 | if (CPUspresent.is_open()) |
| 256 | { |
| 257 | std::string line; |
| 258 | |
| 259 | if (bool(getline(CPUspresent, line))) |
| 260 | { |
| 261 | /* The content of this file is a list of ranges or single values, e.g. |
| 262 | * 0-5, or 1-3,5,7 or similar. As we are interested in the |
| 263 | * max valid ID, we just need to find the last valid |
| 264 | * delimiter ('-' or ',') and parse the integer immediately after that. |
| 265 | */ |
| 266 | auto startfrom = line.begin(); |
| 267 | |
| 268 | for (auto i = line.begin(); i < line.end(); ++i) |
| 269 | { |
| 270 | if (*i == '-' || *i == ',') |
| 271 | { |
| 272 | startfrom = i + 1; |
| 273 | } |
| 274 | } |
| 275 | |
| 276 | line.erase(line.begin(), startfrom); |
| 277 | |
| 278 | max_cpus = support::cpp11::stoi(line, nullptr) + 1; |
| 279 | success = true; |
| 280 | } |
| 281 | } |
| 282 | |
| 283 | // Return std::thread::hardware_concurrency() as a fallback. |
| 284 | if (!success) |
| 285 | { |
| 286 | max_cpus = std::thread::hardware_concurrency(); |
| 287 | } |
| 288 | return max_cpus; |
| 289 | } |
| 290 | #if defined(__ANDROID__) |
| 291 | std::vector<uint32_t> get_cpu_capacities() |
| 292 | { |