Rough script for counting how many events per second you are doing, with rolling average

average_timer.rb

# Usage:
#
# timer = AverageTimer.new
# my_loop do
#   # Track an avent
#   timer.event
#
#   # Print the events per second (averaged over 5 seconds)
#   puts timer.events_per_second(5)
#
#   # Print the events per second (averaged over 30 seconds)
#   puts timer.events_per_second(30)
# end

class AverageTimer
  def initialize(opts={})
    @resolution = opts[:resolution] || 5
    @keep_averages = opts[:keep_averages] || 10

    @count = 0
    @averages = []
  end
  
  def event
    # Start the timer if this is the first event
    @start_time = Time.now if @start_time.nil?

    if @start_time + @resolution < Time.now
      average = @count / @resolution.to_f
      @count = 0
      @start_time = Time.now
      @averages << average
      @averages.last(@keep_averages)
    end
    
    @count += 1
  end
  
  def events_per_second(average_period=5)
    last = @averages.last

    return nil if last.nil?
    return last/@resolution if average_period < @resolution

    num_avgs = [@averages.length, (average_period/@resolution.to_f).ceil].min
    @averages.last(num_avgs).instance_eval { reduce(:+) / size.to_f } / @resolution
  end
end