Testing various Deflate compression parameters...

compare.rb

# Quick comparison of Deflate performance with respec to varios
# LZ77 window and memLevel settings. E.g...
#
# $> curl https://github.com/timeline.json -o timeline.json
# $> ruby compare.rb timeline.json
#

require "zlib"

unless file = ARGV[0]
  puts "Usage: compare.rb <file>"
  exit(1)
end

data = IO.read(file)
puts "Original file (#{file}) size: #{data.size} bytes"

(8..15).each do |window_bits|
  puts "Window size: #{window_bits} bits (#{2**window_bits} bytes)"

  (1..9).each do |memLevel|
    z = Zlib::Deflate.new(nil, window_bits, memLevel)
    dst = z.deflate(data, Zlib::FINISH)
    z.close

    puts "\t memLevel: #{memLevel}, compressed size: #{dst.size} bytes " \
       + "(#{(100-((dst.size.to_f/data.size)*100)).round(2)}% reduction)"
  end
end

github-timeline.sh

igrigorik { ~/Desktop } > ruby compare.rb timeline.json
Original file (timeline.json) size: 30437 bytes
Window size: 8 bits (256 bytes)
	 memLevel: 1, compressed size: 19472 bytes (36.03% reduction)
	 memLevel: 2, compressed size: 17701 bytes (41.84% reduction)
	 memLevel: 3, compressed size: 16574 bytes (45.55% reduction)
	 memLevel: 4, compressed size: 15872 bytes (47.85% reduction)
	 memLevel: 5, compressed size: 15485 bytes (49.12% reduction)
	 memLevel: 6, compressed size: 15306 bytes (49.71% reduction)
	 memLevel: 7, compressed size: 15216 bytes (50.01% reduction)
	 memLevel: 8, compressed size: 15166 bytes (50.17% reduction)
	 memLevel: 9, compressed size: 15116 bytes (50.34% reduction)
Window size: 9 bits (512 bytes)
	 memLevel: 1, compressed size: 19472 bytes (36.03% reduction)
	 memLevel: 2, compressed size: 17701 bytes (41.84% reduction)
	 memLevel: 3, compressed size: 16574 bytes (45.55% reduction)
	 memLevel: 4, compressed size: 15872 bytes (47.85% reduction)
	 memLevel: 5, compressed size: 15485 bytes (49.12% reduction)
	 memLevel: 6, compressed size: 15306 bytes (49.71% reduction)
	 memLevel: 7, compressed size: 15216 bytes (50.01% reduction)
	 memLevel: 8, compressed size: 15166 bytes (50.17% reduction)
	 memLevel: 9, compressed size: 15116 bytes (50.34% reduction)
Window size: 10 bits (1024 bytes)
	 memLevel: 1, compressed size: 16218 bytes (46.72% reduction)
	 memLevel: 2, compressed size: 14881 bytes (51.11% reduction)
	 memLevel: 3, compressed size: 14032 bytes (53.9% reduction)
	 memLevel: 4, compressed size: 13488 bytes (55.69% reduction)
	 memLevel: 5, compressed size: 13220 bytes (56.57% reduction)
	 memLevel: 6, compressed size: 13061 bytes (57.09% reduction)
	 memLevel: 7, compressed size: 12971 bytes (57.38% reduction)
	 memLevel: 8, compressed size: 12921 bytes (57.55% reduction)
	 memLevel: 9, compressed size: 12921 bytes (57.55% reduction)
Window size: 11 bits (2048 bytes)
	 memLevel: 1, compressed size: 9797 bytes (67.81% reduction)
	 memLevel: 2, compressed size: 9077 bytes (70.18% reduction)
	 memLevel: 3, compressed size: 8626 bytes (71.66% reduction)
	 memLevel: 4, compressed size: 8359 bytes (72.54% reduction)
	 memLevel: 5, compressed size: 8180 bytes (73.12% reduction)
	 memLevel: 6, compressed size: 8110 bytes (73.35% reduction)
	 memLevel: 7, compressed size: 8062 bytes (73.51% reduction)
	 memLevel: 8, compressed size: 8062 bytes (73.51% reduction)
	 memLevel: 9, compressed size: 8062 bytes (73.51% reduction)
Window size: 12 bits (4096 bytes)
	 memLevel: 1, compressed size: 8853 bytes (70.91% reduction)
	 memLevel: 2, compressed size: 8228 bytes (72.97% reduction)
	 memLevel: 3, compressed size: 7833 bytes (74.26% reduction)
	 memLevel: 4, compressed size: 7613 bytes (74.99% reduction)
	 memLevel: 5, compressed size: 7489 bytes (75.4% reduction)
	 memLevel: 6, compressed size: 7410 bytes (75.65% reduction)
	 memLevel: 7, compressed size: 7363 bytes (75.81% reduction)
	 memLevel: 8, compressed size: 7363 bytes (75.81% reduction)
	 memLevel: 9, compressed size: 7363 bytes (75.81% reduction)
Window size: 13 bits (8192 bytes)
	 memLevel: 1, compressed size: 8518 bytes (72.01% reduction)
	 memLevel: 2, compressed size: 7928 bytes (73.95% reduction)
	 memLevel: 3, compressed size: 7537 bytes (75.24% reduction)
	 memLevel: 4, compressed size: 7316 bytes (75.96% reduction)
	 memLevel: 5, compressed size: 7199 bytes (76.35% reduction)
	 memLevel: 6, compressed size: 7162 bytes (76.47% reduction)
	 memLevel: 7, compressed size: 7114 bytes (76.63% reduction)
	 memLevel: 8, compressed size: 7112 bytes (76.63% reduction)
	 memLevel: 9, compressed size: 7114 bytes (76.63% reduction)
Window size: 14 bits (16384 bytes)
	 memLevel: 1, compressed size: 8368 bytes (72.51% reduction)
	 memLevel: 2, compressed size: 7814 bytes (74.33% reduction)
	 memLevel: 3, compressed size: 7440 bytes (75.56% reduction)
	 memLevel: 4, compressed size: 7225 bytes (76.26% reduction)
	 memLevel: 5, compressed size: 7108 bytes (76.65% reduction)
	 memLevel: 6, compressed size: 7083 bytes (76.73% reduction)
	 memLevel: 7, compressed size: 7036 bytes (76.88% reduction)
	 memLevel: 8, compressed size: 7034 bytes (76.89% reduction)
	 memLevel: 9, compressed size: 7036 bytes (76.88% reduction)
Window size: 15 bits (32768 bytes)
	 memLevel: 1, compressed size: 8327 bytes (72.64% reduction)
	 memLevel: 2, compressed size: 7787 bytes (74.42% reduction)
	 memLevel: 3, compressed size: 7410 bytes (75.65% reduction)
	 memLevel: 4, compressed size: 7201 bytes (76.34% reduction)
	 memLevel: 5, compressed size: 7089 bytes (76.71% reduction)
	 memLevel: 6, compressed size: 7065 bytes (76.79% reduction)
	 memLevel: 7, compressed size: 7027 bytes (76.91% reduction)
	 memLevel: 8, compressed size: 7024 bytes (76.92% reduction)
	 memLevel: 9, compressed size: 7027 bytes (76.91% reduction)