os::is_server_class_machine() could return incorrect result if a host's cpu have a few logical cores.
For example if a host has 2 physical cores with 2 threads on each this host is not considered as server class machine despite https://docs.oracle.com/javase/8/docs/technotes/guides/vm/gctuning/ergonomics.html#sthref5 says:
"2 or more physical processors."

The code :
    const unsigned int logical_processors =
      VM_Version::logical_processors_per_package();
    if (logical_processors > 1) {
      const unsigned int physical_packages =
        os::active_processor_count() / logical_processors;
      if (physical_packages > server_processors) {
        result = true;
      }
  the line "if (physical_packages > server_processors)" should be "if (physical_packages >= server_processors)" to comply with description.