Impact of stack size on exceptions performance

results.txt

$ ruby -v
ruby 2.7.1p83 (2020-03-31 revision a0c7c23c9c) [x86_64-darwin17]
$ ruby yield-vs-block.rb
Nested yield stack size: 402
Forward block stack size: 202
Warming up --------------------------------------
            baseline    82.138k i/100ms
        nested-yield    16.030k i/100ms
       forward-block    28.945k i/100ms
Calculating -------------------------------------
            baseline    816.998k (± 2.9%) i/s -      4.107M in   5.031495s
        nested-yield    178.248k (± 4.4%) i/s -    897.680k in   5.046095s
       forward-block    280.624k (± 4.5%) i/s -      1.418M in   5.064693s

Comparison:
            baseline:   816998.1 i/s
       forward-block:   280623.7 i/s - 2.91x  (± 0.00) slower
        nested-yield:   178247.6 i/s - 4.58x  (± 0.00) slower

yield-vs-block.rb

require 'benchmark/ips'

module Bench
  extend self

  DummyError = Class.new(StandardError)

  STACK_SIZE = Integer(ENV.fetch("STACK_SIZE", 200))

  def nested_yield_0
    yield
  end

  def forward_block_0
    yield
  end

  (1..STACK_SIZE).each do |i|
    class_eval(<<~RUBY, __FILE__, __LINE__ + 1)
      def nested_yield_#{i}
        nested_yield_#{i - 1} { yield }
      end

      def forward_block_#{i}(&block)
        forward_block_#{i - 1}(&block)
      end
    RUBY
  end

  alias_method :nested_yield, :"nested_yield_#{STACK_SIZE}"
  alias_method :forward_block, :"forward_block_#{STACK_SIZE}"
end

puts "Nested yield stack size: #{Bench.nested_yield { caller.size }}"
puts "Forward block stack size: #{Bench.forward_block { caller.size }}"


Benchmark.ips do |x|
  x.report('baseline') do |times|
    i = 0
    while i < times
      begin
        raise Bench::DummyError
      rescue Bench::DummyError
      end
      i += 1
    end
  end

  x.report('nested-yield') do |times|
    Bench.nested_yield do
      i = 0
      while i < times
        begin
          raise Bench::DummyError
        rescue Bench::DummyError
        end
        i += 1
      end
    end
  end

  x.report('forward-block') do |times|
    Bench.forward_block do
      i = 0
      while i < times
        begin
          raise Bench::DummyError
        rescue Bench::DummyError
        end
        i += 1
      end
    end
  end
  x.compare!
end