struct.rb

class A < Struct.new(:a, :b)
end
B = Struct.new(:a, :b)

require 'benchmark'

Benchmark.bmbm 20 do |r|
  n = 10_000_000

  a = A.new(1,2)
  b = B.new(1,2)

  r.report('initialize inherited Struct'){ n.times{ A.new(1,2) } }
  r.report('initialize assigned Struct'){  n.times{ B.new(1,2) } }

  r.report('access inherited Struct'){ n.times{ a.a; a.b } }
  r.report('access assigned Struct'){  n.times{ b.a; b.b } }
end

# Rehearsal ---------------------------------------------------------------
# initialize inherited Struct  22.610000   0.030000  22.640000 ( 22.762717)
# initialize assigned Struct   21.640000   0.050000  21.690000 ( 21.816132)
# access inherited Struct       5.390000   0.000000   5.390000 (  5.410279)
# access assigned Struct        5.380000   0.020000   5.400000 (  5.416878)
# ----------------------------------------------------- total: 55.120000sec

#                                   user     system      total        real
# initialize inherited Struct  22.630000   0.030000  22.660000 ( 22.669520)
# initialize assigned Struct   22.830000   0.040000  22.870000 ( 22.878188)
# access inherited Struct       5.450000   0.010000   5.460000 (  5.471413)
# access assigned Struct        5.750000   0.010000   5.760000 (  5.766549)