code

require 'benchmark/ips'

n = (ARGV[0] || 1).to_i

eval <<CODE
def bg
  #{'a = block_given?;' * n}
  a
end

def dy
  #{'a = defined?(yield);' * n}
  a
end

def b(&block)
  #{'a = block;' * n}
  a
end
CODE

block = proc{}

puts "With passed block"
Benchmark.ips do |x|
  x.report("block_given?"){bg(&block)}
  x.report("defined?(yield)"){dy(&block)}
  x.report("&block"){b(&block)}
  x.compare!
end

puts "With block"
Benchmark.ips do |x|
  x.report("block_given?"){bg{}}
  x.report("defined?(yield)"){dy{}}
  x.report("&block"){b{}}
  x.compare!
end

puts "Without block"
Benchmark.ips do |x|
  x.report("block_given?"){bg}
  x.report("defined?(yield)"){dy}
  x.report("&block"){b}
  x.compare!
end

ruby 3.0.2 results

With passed block
Warming up --------------------------------------
        block_given?   247.543k i/100ms
     defined?(yield)   309.646k i/100ms
              &block   282.631k i/100ms
Calculating -------------------------------------
        block_given?      2.477M (_ 0.3%) i/s -     12.625M in   5.095886s
     defined?(yield)      3.098M (_ 0.3%) i/s -     15.792M in   5.096976s
              &block      2.814M (_ 0.1%) i/s -     14.132M in   5.021455s

Comparison:
     defined?(yield):  3098321.7 i/s
              &block:  2814235.3 i/s - 1.10x  (_ 0.00) slower
        block_given?:  2477458.0 i/s - 1.25x  (_ 0.00) slower

With block
Warming up --------------------------------------
        block_given?   282.683k i/100ms
     defined?(yield)   350.667k i/100ms
              &block    71.141k i/100ms
Calculating -------------------------------------
        block_given?      2.826M (_ 0.1%) i/s -     14.134M in   5.002070s
     defined?(yield)      3.552M (_ 0.1%) i/s -     17.884M in   5.034722s
              &block    712.031k (_ 1.3%) i/s -      3.628M in   5.096509s

Comparison:
     defined?(yield):  3552137.7 i/s
        block_given?:  2825663.9 i/s - 1.26x  (_ 0.00) slower
              &block:   712031.2 i/s - 4.99x  (_ 0.00) slower

Without block
Warming up --------------------------------------
        block_given?   286.115k i/100ms
     defined?(yield)   396.456k i/100ms
              &block   330.508k i/100ms
Calculating -------------------------------------
        block_given?      2.865M (_ 0.2%) i/s -     14.592M in   5.093600s
     defined?(yield)      4.005M (_ 0.1%) i/s -     20.219M in   5.048443s
              &block      3.321M (_ 0.1%) i/s -     16.856M in   5.074991s

Comparison:
     defined?(yield):  4005051.5 i/s
              &block:  3321368.6 i/s - 1.21x  (_ 0.00) slower
        block_given?:  2864754.3 i/s - 1.40x  (_ 0.00) slower