Benchmark various variants of parsing durations in Rails' ActiveSupport

benchmark_duration_parsing.rb

require 'benchmark/ips'
require 'active_support/duration'

EPOCH = ::Time.utc(2000)

PARTS_IN_SECONDS = {
  seconds:                     1, # Used in parse method for ease of handling part hashes with seconds
  minutes:                    60,
  hours:                 60 * 60,
  days:             24 * 60 * 60,
  weeks:     7    * 24 * 60 * 60,
  months:   30    * 24 * 60 * 60,
  years:   365.25 * 24 * 60 * 60,
}.freeze

def parse_initial(iso8601duration)
  parts = ActiveSupport::Duration::ISO8601Parser.new(iso8601duration).parse!
  time  = ::Time.current
  ActiveSupport::Duration.new(time.advance(parts) - time, parts)
end

def parse_epoch(iso8601duration)
  parts = ActiveSupport::Duration::ISO8601Parser.new(iso8601duration).parse!
  ActiveSupport::Duration.new(EPOCH.advance(parts) - EPOCH, parts)
end

def parse_inject_parts(iso8601duration)
  parts = ActiveSupport::Duration::ISO8601Parser.new(iso8601duration).parse!
  total_seconds = parts.inject(0) do |total, (part, value)|
    total + value * PARTS_IN_SECONDS[part]
  end
  ActiveSupport::Duration.new(total_seconds, parts)
end

def year_initial
  ActiveSupport::Duration.new(1 * 365.25.days.to_i, [[:years, 1]])
end

def year_with_parts
  ActiveSupport::Duration.new(1 * ActiveSupport::Duration::PARTS_IN_SECONDS[:years].to_i, [[:years, 1]])
end

ISO8601_SAMPLE = 'P1Y1M1DT1H1M1.0S'

Benchmark.ips do |x|
  x.report("Initial parse with TimeWithZone#advance")     { parse_initial(ISO8601_SAMPLE) }
  x.report("Parse with Time#advance from fixed EPOCH")    { parse_epoch(ISO8601_SAMPLE) }
  x.report("Parse using sum of mapping parts to seconds") { parse_inject_parts(ISO8601_SAMPLE) }
  x.compare!
end

Benchmark.ips do |x|
  x.report("Initial 1.year with many intermediate durations")  { year_initial }
  x.report("1.year2 with mapping duration to seconds")         { year_with_parts }
  x.compare!
end

output.txt

Warming up --------------------------------------
Initial parse with TimeWithZone#advance
                         1.050k i/100ms
Parse with Time#advance from fixed EPOCH
                         1.683k i/100ms
Parse using sum of mapping parts to seconds
                         2.695k i/100ms
Calculating -------------------------------------
Initial parse with TimeWithZone#advance
                         10.651k (± 2.8%) i/s -     53.550k in   5.031816s
Parse with Time#advance from fixed EPOCH
                         17.252k (± 5.2%) i/s -     87.516k in   5.088071s
Parse using sum of mapping parts to seconds
                         27.991k (± 2.3%) i/s -    140.140k in   5.009231s

Comparison:
Parse using sum of mapping parts to seconds:    27991.0 i/s
Parse with Time#advance from fixed EPOCH:    17252.5 i/s - 1.62x  slower
Initial parse with TimeWithZone#advance:    10650.5 i/s - 2.63x  slower

Warming up --------------------------------------
Initial 1.year with many intermediate durations
                        27.250k i/100ms
1.year2 with mapping duration to seconds
                        44.715k i/100ms
Calculating -------------------------------------
Initial 1.year with many intermediate durations
                        325.580k (± 4.6%) i/s -      1.635M in   5.032719s
1.year2 with mapping duration to seconds
                        672.955k (± 4.7%) i/s -      3.398M in   5.060281s

Comparison:
1.year2 with mapping duration to seconds:   672955.2 i/s
Initial 1.year with many intermediate durations:   325579.6 i/s - 2.07x  slower