Benchmarking time zone lookups

tz_lookup_bench.rb

# frozen_string_literal: true

require "benchmark"

# https://github.com/zverok/wheretz
require "json" # Should be required by wheretz but it isn't currently
require "wheretz"

# https://github.com/HarlemSquirrel/tzf-rb
require "tzf"

ITERATIONS = 1000
THREAD_COUNT = 4

def lookup(lib_name:, lat:, lng:)
  case lib_name
  in :wheretz
    # WhereTZ raises an argument error when the point is out of any known time zone.
    WhereTZ.lookup(lat, lng) rescue ArgumentError
  in :tzf
    TZF.tz_name(lat, lng)
  end
end

def iteration_lookups(lib_name:)
  ITERATIONS.times do |i|
    offset = (360.0 / ITERATIONS) * i

    lat = (180 - offset)
    lng = (180 - offset)
    lookup(lib_name:, lat:, lng:)

    lat = (-180 + offset)
    lng = (180 - offset)
    lookup(lib_name:, lat:, lng:)

    lat = (180 - offset)
    lng = (-180 + offset)
    lookup(lib_name:, lat:, lng:)
  end
end

puts "Ruby #{RUBY_VERSION}"
puts "Benchmarking #{ITERATIONS} lookups in #{THREAD_COUNT} threads..."

Benchmark.bmbm do |x|
  x.report("WhereTZ.lookup") do
    threads = []

    THREAD_COUNT.times do
      threads << Thread.new { iteration_lookups(lib_name: :wheretz) }
    end

    threads.each(&:join)
  end

  x.report("TZF.tz_name") do
    threads = []

    THREAD_COUNT.times do
      threads << Thread.new { iteration_lookups(lib_name: :tzf) }
    end

    threads.each(&:join)
  end
end