bench_sd.rb

require 'benchmark_driver'
Benchmark.driver do |x|
  x.prelude <<~EOS
    # frozen_string_literal: true
    @world = 'world'
  EOS
  x.report 'array', %q{
    buf = []
    buf << 'hello, '
    buf << @world.to_s
    buf.join
  }
  x.report 'hybrid', %q{
    buf = []
    buf << "hello, #{@world}"
    buf.join
  }
end

result_sd.log

Warming up --------------------------------------
               array     4.435M i/s -      4.661M times in 1.051023s (225.49ns/i, 902clocks/i)
              hybrid     4.089M i/s -      4.092M times in 1.000707s (244.58ns/i)
Calculating -------------------------------------
               array     4.673M i/s -     13.305M times in 2.847078s (213.99ns/i, 926clocks/i)
              hybrid     4.307M i/s -     12.266M times in 2.848049s (232.19ns/i, 974clocks/i)

Comparison:
               array:   4673041.7 i/s
              hybrid:   4306811.8 i/s - 1.09x  slower