prelude: |
  # one thread, one mutex (no contention)
benchmark:
  vm_thread_mutex1: |

    require 'thread'
    m = Thread::Mutex.new
    r = 0
    max = 2000
    lmax = max * max
    (1..1).map{
      Thread.new{
        i = 0
        while i<lmax
          i += 1
          m.synchronize{
            r += 1
          }
        end
      }
    }.each{|e|
      e.join
    }
    raise r.to_s if r != max * max
loop_count: 1