bench.rb

require 'benchmark'
require 'set'
#require 'rbtree'

range = (1..10_000)
array = range.to_a
set = SortedSet.new array

n = 1..1_000

puts "#{RUBY_ENGINE} #{RUBY_VERSION} #{RUBY_PLATFORM}"
Benchmark.bm(9) do |x|
  x.report("clone ary:"){ for i in n do; array.clone; end }
  x.report("clone set:"){ for i in n do; set.clone; end }
  x.report("array:"){ for i in n do; array.clone.delete rand range; end }
  x.report("set:"){ for i in n do; set.clone.delete rand range; end }
end

output

ruby 2.2.3 x86_64-linux
                user     system      total        real
clone ary:  0.000000   0.000000   0.000000 (  0.000217)
clone set:  2.280000   0.020000   2.300000 (  2.307867)
array:      0.280000   0.000000   0.280000 (  0.280849) # 0.280849 - 0.000217 = ~0.280632
set:        2.250000   0.000000   2.250000 (  2.256817) # 2.307867 - 2.256817 = ~0.05105

jruby 2.2.2 java
                user     system      total        real
clone ary:  0.020000   0.000000   0.020000 (  0.002725)
clone set:  0.570000   0.040000   0.610000 (  0.347833)
array:      0.200000   0.000000   0.200000 (  0.082413)
set:        0.500000   0.010000   0.510000 (  0.312068)