require 'fruity'

a = (1..100).to_a.shuffle
compare do
  sort     { a.sort{|x, y| y <=> x} }
  sort_by  { a.sort_by{|x| -x} }
  reverse  { a.sort.reverse }
  reverse! { a.sort.reverse! }
end

# reverse! is faster than reverse by 10% ± 1.0%
# reverse is faster than sort_by by 6x ± 0.1
# sort_by is faster than sort by 60% ± 1.0%