gistfile1.rb

require 'thread'
require 'benchmark'

N = 200000

def competition(&block)
   t1 = Thread.new {
      for i in 1..N
         block.call
      end
   }
   t2 = Thread.new {
      for i in 1..N
         block.call
      end
   }
   t1.join
   t2.join
end

def lock_delete
   File.open("lock_delete", "w").flock(File::LOCK_EX)
   File.delete("lock_delete")
end

def lock_unlock
   f = File.open("lock_unlock", "w")
   f.flock(File::LOCK_EX)
   f.flock(File::LOCK_UN)
end

Benchmark.bm do |x|
   x.report("lock delete:") { for i in 1..N; lock_delete; end }
   x.report("lock unlock:") { for i in 1..N; lock_unlock; end }

   x.report("2 lock delete:") { competition { lock_delete rescue '' } } # have to rescue Errno::ENOENT
   x.report("2 lock unlock:") { competition { lock_unlock } }
end

gistfile2.txt

      user     system      total        real
lock delete:  1.270000   2.300000   3.570000 (  8.243337)
lock unlock:  1.060000   0.650000   1.710000 (  4.001936)
2 lock delete:  2.820000   4.670000   7.490000 ( 17.281890)
2 lock unlock:  2.270000   1.480000   3.750000 (  8.710531)