the former is normal trunk, the latter is multi-delete patched

delete multi bench

D:\> type bench.rb
require 'benchmark'
REPEAT = 10_000_000
Benchmark.bm do |x|
  x.report do
    REPEAT.times do
      [1,2,3,4,5].delete(1)
    end
  end
end

D:\> ruby\miniruby.rb -Iruby/lib bench.rb
       user     system      total        real
   5.055000   0.000000   5.055000 (  5.060912)

D:\> ruby\miniruby.rb -Iruby/lib bench.rb
       user     system      total        real
   4.945000   0.000000   4.945000 (  4.977151)