check.rb

require 'benchmark/ips'
require 'monitor'

class MonitorCounter
  def initialize
    @counter = 0
    # No idea why this doesn't work inside the class declaration
    extend(MonitorMixin)
  end

  def incr
    synchronize { @counter = @counter + 1 }
  end

  def value
    @counter
  end
end

class StraightCounter
  def initialize
    @counter = 0
  end

  def incr
    @counter = @counter + 1
  end

  def value
    @counter
  end
end

monitored = MonitorCounter.new
straight = StraightCounter.new

Benchmark.ips do |x|
  x.config(time: 10, warmup: 20)

  x.report("Monitor") { monitored.incr }
  x.report("Straght") { straight.incr }
end

monitored = MonitorCounter.new
straight = StraightCounter.new

TIMES = 10_000_000

Benchmark.bmbm do |x|
  x.report("Straight") { TIMES.times { straight.incr } }
  x.report("Monitored")  { TIMES.times { monitored.incr } }
end

# Calculating -------------------------------------
#              Monitor   109.513k i/100ms
#              Straght   235.768k i/100ms
# -------------------------------------------------
#              Monitor      1.899M (± 5.4%) i/s -     18.946M
#              Straght     11.272M (± 7.3%) i/s -    111.990M

# Rehearsal ---------------------------------------------
# Straight    0.930000   0.050000   0.980000 (  0.638000)
# Monitored   5.890000   0.080000   5.970000 (  5.239000)
# ------------------------------------ total: 6.950000sec
# 
#                 user     system      total        real
# Straight    0.590000   0.000000   0.590000 (  0.588000)
# Monitored   5.090000   0.030000   5.120000 (  5.086000)
# true
# [20000000, 20000000]