benchmark_array_sort.rb

require 'benchmark/ips'

hash_array = (1..10000).map{|n| {name: "foo#{n}"}}

Benchmark.ips do |x|
  x.time = 100

  x.report("reverse") do
    hash_array.sort_by!{|v| v[:name]}
    hash_array.reverse!
  end

  x.report("minus") do
    hash_array.sort! do |v1, v2|
      n = v1[:name] <=> v2[:name]
      n * -1
    end
  end

  x.compare!
end

# 実行結果
Calculating -------------------------------------
             reverse    35.000  i/100ms
               minus    43.000  i/100ms
-------------------------------------------------
             reverse    401.677  (± 7.7%) i/s -      2.030k
               minus    449.311  (±10.2%) i/s -      2.236k

Comparison:
               minus:      449.3 i/s
             reverse:      401.7 i/s - 1.12x slower