logging and string interpolation

bm.rb

require 'benchmark'                                                                                                                                                       
require 'logger'                                                                                                                                                          
                                                                                                                                                                          
iterations = 1000000                                                                                                                                                      
                                                                                                                                                                          
logger = Logger.new(STDOUT)                                                                                                                                               
logger.level = Logger::ERROR                                                                                                                                              
                                                                                                                                                                          
bar = 'bar'                                                                                                                                                               
foo = 'foo'                                                                                                                                                               
def method                                                                                                                                                                
  'method'                                                                                                                                                                
end                                                                                                                                                                       
                                                                                                                                                                          
Benchmark.bmbm(20) do |bm|                                                                                                                                                
  bm.report('{ "foo #{bar}" }') do                                                                                                                                        
    iterations.times do                                                                                                                                                   
      logger.debug { "foo #{bar}" }                                                                                                                                       
    end                                                                                                                                                                   
  end                                                                                                                                                                     
  bm.report('"#{method} bar"') do                                                                                                                                         
    iterations.times do                                                                                                                                                   
      logger.debug "#{method} bar"                                                                                                                                        
    end                                                                                                                                                                   
  end                                                                                                                                                                     
  bm.report('"#{foo} #{bar}"') do                                                                                                                                         
    iterations.times do                                                                                                                                                   
      logger.debug "#{foo} #{bar}"                                                                                                                                        
    end                                                                                                                                                                   
  end                                                                                                                                                                     
  bm.report('"foo #{bar}"') do                                                                                                                                            
    iterations.times do                                                                                                                                                   
      logger.debug "foo #{bar}"                                                                                                                                           
    end                                                                                                                                                                   
  end                                                                                                                                                                     
  bm.report('"foo bar"') do                                                                                                                                               
    iterations.times do                                                                                                                                                   
      logger.debug "foo bar"                                                                                                                                              
    end                                                                                                                                                                   
  end                                                                                                                                                                     
end

gistfile1.txt

                           user     system      total        real
{ "foo #{bar}" }       0.430000   0.000000   0.430000 (  0.423957)
"#{method} bar"        0.400000   0.000000   0.400000 (  0.399179)
"#{foo} #{bar}"        0.380000   0.000000   0.380000 (  0.377865)
"foo #{bar}"           0.300000   0.000000   0.300000 (  0.304749)
"foo bar"              0.220000   0.000000   0.220000 (  0.214499)