prelude: |
  short_lived_ary = []

  if RUBY_VERSION >= "2.2.0"
    GC.start(full_mark: false, immediate_mark: true, immediate_sweep: true)
  end

  short_lived = ''
benchmark:
  vm1_gc_wb_ary: |
    short_lived_ary[0] = short_lived # write barrier
loop_count: 30000000