diff --git a/examples/common.cpp b/examples/common.cpp index 86c1eef..259880a 100644 --- a/examples/common.cpp +++ b/examples/common.cpp @@ -8,6 +8,7 @@ #include #include #include +#include #if defined(__APPLE__) && defined(__MACH__) #include @@ -28,21 +29,21 @@ int32_t get_num_physical_cores() { #ifdef __linux__ - std::ifstream cpuinfo("/proc/cpuinfo"); - std::string line; - while (std::getline(cpuinfo, line)) { - std::size_t pos = line.find("cpu cores"); - if (pos != std::string::npos) { - pos = line.find(": ", pos); - if (pos != std::string::npos) { - try { - // Extract the number and return it - return static_cast(std::stoul(line.substr(pos + 2))); - } catch (const std::invalid_argument &) { - // Ignore if we could not parse - } - } + // enumerate the set of thread siblings, num entries is num cores + std::unordered_set siblings; + for (uint32_t cpu=0; cpu < UINT32_MAX; ++cpu) { + std::ifstream thread_siblings("/sys/devices/system/cpu" + + std::to_string(cpu) + "/topology/thread_siblings"); + if (!thread_siblings.is_open()) { + break; // no more cpus } + std::string line; + if (std::getline(thread_siblings, line)) { + siblings.insert(line); + } + } + if (siblings.size() > 0) { + return static_cast(siblings.size()); } #elif defined(__APPLE__) && defined(__MACH__) int32_t num_physical_cores;