I don't understand why.
{
    
    auto read_from = [](const char * filename, int default_value) -> int {
        std::ifstream infile(filename);
        if (!infile.is_open())
        {
            return default_value;
        }
        int idata;
        if (infile >> idata)
            return idata;
        else
            return default_value;
    };
    unsigned quota_count = default_cpu_count;
    
    
    int cgroup_quota = read_from("/sys/fs/cgroup/cpu/cpu.cfs_quota_us", -1);
    int cgroup_period = read_from("/sys/fs/cgroup/cpu/cpu.cfs_period_us", -1);
    if (cgroup_quota > -1 && cgroup_period > 0)
    {
        quota_count = ceil(static_cast<float>(cgroup_quota) / static_cast<float>(cgroup_period));
    }
    return std::min(default_cpu_count, quota_count);
}
#endif 
unsigned getNumberOfPhysicalCPUCores()