AFAIK no, HT siblings do not get a lower priority. The core's resources are shared equally between the SMT threads. Operating systems that are SMT aware try to

AFAIK no, HT siblings do not get a lower priority. The core's resources are shared equally between the SMT threads. Operating systems that are SMT aware try to avoid this sharing when possible (a non-SMT-aware OS could schedule a pair of runnable threads on one core while another core is idle; a SMT-aware OS would use the idle core instead, so both threads get a full core for themselves).