measurer

measurer.rb

# Measures runtime, memory usage,
# of GC calls
class Measurer
  require "json"
  require "benchmark"

  def self.measure(opts = {}, &block)
    use_gc = opts.has_key?(:use_gc) ? opts[:use_gc] : true
    if use_gc
      # collect memory allocated during library loading
      # and our own code before the measurement
      GC.start
    else
      GC.disable
    end
    memory_before = `ps -o rss= -p #{Process.pid}`.to_i/1024
    gc_stat_before = GC.stat
    time = Benchmark.realtime do
      yield
    end
    gc_stat_after = GC.stat
    GC.start if use_gc
    memory_after = `ps -o rss= -p #{Process.pid}`.to_i/1024
    GC.enable
    puts({
      RUBY_VERSION => {
        gc: use_gc ? 'enabled' : 'disabled',
        time: time.round(2),
        gc_count: gc_stat_after[:count] - gc_stat_before[:count], memory: "%dM" % (memory_after - memory_before)
      } }.to_json)
  end
end

Adapted from Ruby Performance Optimization

Usage:

load 'measurer.rb'
require 'csv'
csv = '/Users/Bodah/Downloads/FL_insurance_sample.csv'

Measurer.measure {  CSV.open(csv).readlines.map { |line| line.map { |col| col.downcase.gsub(/\b('?[a-z])/) { $1.capitalize } } }}
=> {"2.1.3":{"gc":"enabled","time":1.69,"gc_count":14,"memory":"152M"}}

Measurer.measure(use_gc: false) {  CSV.open(csv).readlines.map { |line| line.map { |col| col.downcase.gsub(/\b('?[a-z])/) { $1.capitalize } } }}
=> {"2.1.3":{"gc":"disabled","time":1.64,"gc_count":0,"memory":"190M"}}