Some microbenchmarks:

CURRENT MASTER:

Variable and attribute read access:
   4.5 ns       read_local
   5.8 ns       read_nonlocal
   7.8 ns       read_global
   7.8 ns       read_builtin
  21.2 ns       read_classvar_from_class
  19.1 ns       read_classvar_from_instance
  16.4 ns       read_instancevar
  23.6 ns       read_instancevar_slots
  20.2 ns       read_namedtuple
  40.5 ns       read_boundmethod

PR 24216

Variable and attribute read access:
   4.5 ns       read_local
   5.8 ns       read_nonlocal
   7.8 ns       read_global
   8.2 ns       read_builtin
  21.4 ns       read_classvar_from_class
  19.0 ns       read_classvar_from_instance
  16.6 ns       read_instancevar
  10.2 ns       read_instancevar_slots
  20.5 ns       read_namedtuple
  42.9 ns       read_boundmethod