Quad Related Hash lookup benchmarks

gistfile1.rb

require 'benchmark/ips'

substitutions = {
  'true' => true,
  'false' => false,
  'null' => nil,
  '' => nil
}.freeze

Benchmark.ips do |x|
  x.report("match: fetch") do
    token = 'null'.freeze
    substitutions.fetch(token, token)
  end

  x.report("match: fetch-block") do
    token = 'null'.freeze
    substitutions.fetch(token) { token }
  end

  x.report("match: lookup") do
    token = 'null'.freeze
    substitutions.has_key?(token) ? substitutions[token] : token
  end

  x.report("no match: fetch") do
    token = 'no match'.freeze
    substitutions.fetch(token, token)
  end

  x.report("no match: fetch-block") do
    token = 'no match'.freeze
    substitutions.fetch(token) { token }
  end

  x.report("no match: lookup") do
    token = 'no match'.freeze
    substitutions.has_key?(token) ? substitutions[token] : token
  end

  x.compare!
end

__END__

These benchmarks were taken on a 2012 13-inch MacBook Air:

- OS X Yosemite 10.10.3 (14D136)
- 1.8 GHz Intel Core i5
- 8 GB 1600 MHz DDR3
- Ruby 2.2.2

Perhaps most surprisingly the "no match: lookup" case was the fastest. Followed
by all of the fetch options, with the matched being faster than the
non-matched. Falling in the end was the match with the lookup. The slowest was
the non-matching fetch with a block, which makes sense as the block needs to be
executed in this case.

The match with fecth was about the same irrespective of the block and non-block
form. I speculate this is largely due to this specific data set. Normally the
block defers the cost of whatever it does, while the parameter version needs to
create the value at send time. In this case the lookup is the same as the value
so there is no additional cost.

Calculating -------------------------------------
        match: fetch    71.935k i/100ms
  match: fetch-block    54.577k i/100ms
       match: lookup    70.154k i/100ms
     no match: fetch    73.544k i/100ms
no match: fetch-block
                        68.751k i/100ms
    no match: lookup    74.445k i/100ms
-------------------------------------------------
        match: fetch      3.760M (±11.6%) i/s -     18.559M
  match: fetch-block      3.751M (±12.0%) i/s -     18.447M
       match: lookup      3.130M (± 9.7%) i/s -     15.504M
     no match: fetch      3.611M (±12.6%) i/s -     17.724M
no match: fetch-block
                          2.715M (± 8.1%) i/s -     13.475M
    no match: lookup      4.123M (±10.4%) i/s -     20.398M

Comparison:
    no match: lookup:  4123314.2 i/s
        match: fetch:  3759809.8 i/s - 1.10x slower
  match: fetch-block:  3751386.4 i/s - 1.10x slower
     no match: fetch:  3610654.1 i/s - 1.14x slower
       match: lookup:  3129816.3 i/s - 1.32x slower
no match: fetch-block:  2714922.0 i/s - 1.52x slower