benchmark.rb

require 'benchmark/ips'
require 'set'

arr1 = [1,2,3]
arr2 = [1,2,3,4]

s1 = arr1.to_set
s2 = arr2.to_set

Benchmark.ips do  |benchmark|
  benchmark.report('array subtraction') { (arr1 -  arr2).empty?}
  benchmark.report('and operator') { (arr1 & arr2).size == arr1.size }
  benchmark.report('set operation') { s1.subset? s2 }
  benchmark.report('set conversion') { arr1.to_set.subset? arr2.to_set }
  benchmark.report('all function') { arr1.all? {|val|  arr2.include? val } }
  benchmark.compare!
end 

console.log

Warming up --------------------------------------
   array subtraction   100.925k i/100ms
        and operator    83.820k i/100ms
       set operation   151.517k i/100ms
      set conversion    16.651k i/100ms
        all function   115.905k i/100ms
Calculating -------------------------------------
   array subtraction      1.574M (± 5.5%) i/s -      7.872M in   5.018468s
        and operator      1.451M (± 4.4%) i/s -      7.292M in   5.035548s
       set operation      3.185M (±10.3%) i/s -     15.758M in   5.028507s
      set conversion    194.785k (± 8.8%) i/s -    965.758k in   5.015070s
        all function      1.788M (± 4.2%) i/s -      8.925M in   5.001685s

Comparison:
       set operation:  3184869.5 i/s
        all function:  1787595.0 i/s - 1.78x  slower
   array subtraction:  1573641.1 i/s - 2.02x  slower
        and operator:  1451096.7 i/s - 2.19x  slower
      set conversion:   194784.8 i/s - 16.35x  slower