Ruby next and +

bench-fixnum.rb

require 'benchmark/ips'

ARRAY = [*1..1000]

def one_plus
  ARRAY.each { |a| 1 + a }
end

def plus_one
  ARRAY.each { |a| a + 1 }
end

def next_number
  ARRAY.each { |a| a.next }
end

def next_direct_number
  ARRAY.each { |a| 1.next }
end

def send_one_plus
  ARRAY.each { |a| 1.send(:+, a) }
end

def send_plus_one
  ARRAY.each { |a| a.send(:+, 1) }
end

def send_next_number
  ARRAY.each { |a| a.send(:next) }
end

def send_next_direct_number
  ARRAY.each { |a| 1.send(:next) }
end

Benchmark.ips do |bm|
  bm.report('1 + n') { one_plus }
  bm.report('n + 1') { plus_one }
  bm.report('n.next') { next_number }
  bm.report('1.next') { next_direct_number }

  bm.report('send 1 + n') { send_one_plus }
  bm.report('send n + 1') { send_plus_one }
  bm.report('send n.next') { send_next_number }
  bm.report('send 1.next') { send_next_direct_number }

  bm.compare!
end

results.txt

Warming up --------------------------------------
               1 + n     2.190k i/100ms
               n + 1     2.255k i/100ms
              n.next     1.742k i/100ms
              1.next     1.772k i/100ms
          send 1 + n     1.080k i/100ms
          send n + 1     1.061k i/100ms
         send n.next     1.076k i/100ms
         send 1.next     1.191k i/100ms
Calculating -------------------------------------
               1 + n     21.053k (±13.9%) i/s -    102.930k in   5.010651s
               n + 1     22.159k (± 9.5%) i/s -    110.495k in   5.042680s
              n.next     17.642k (± 9.2%) i/s -     88.842k in   5.096675s
              1.next     17.488k (± 9.4%) i/s -     86.828k in   5.022953s
          send 1 + n     11.169k (± 7.5%) i/s -     56.160k in   5.061649s
          send n + 1     11.066k (± 7.7%) i/s -     55.172k in   5.019816s
         send n.next     11.745k (± 9.4%) i/s -     58.104k in   5.001579s
         send 1.next     11.716k (± 9.5%) i/s -     58.359k in   5.034780s

Comparison:
               n + 1:    22158.6 i/s
               1 + n:    21052.9 i/s - same-ish: difference falls within error
              n.next:    17642.2 i/s - 1.26x  slower
              1.next:    17487.9 i/s - 1.27x  slower
         send n.next:    11745.4 i/s - 1.89x  slower
         send 1.next:    11716.1 i/s - 1.89x  slower
          send 1 + n:    11168.9 i/s - 1.98x  slower
          send n + 1:    11066.3 i/s - 2.00x  slower