Performance comparison: strings vs symbols in Ruby

report.txt

ruby symbols-performance.rb 
Rehearsal ------------------------------------
   0.540000   0.010000   0.550000 (  0.543421)
   0.680000   0.020000   0.700000 (  0.705931)
--------------------------- total: 1.250000sec

       user     system      total        real
   0.240000   0.000000   0.240000 (  0.244554)
   0.380000   0.000000   0.380000 (  0.391517)

symbols-performance.rb

require 'benchmark'

hashes = []
1_000_000.times { hashes << { some_key_name: 1, 'some_key_name' => 2 }}
Benchmark.bmbm do |x|
  x.report { hashes.map{|h| h[:some_key_name]} }
  x.report { hashes.map{|h| h['some_key_name']} }
end