Poor man's profiler for Ruby

debugging-poor.rb

# chp2/wrapper.rb
     
require ​"json"
     
require ​"benchmark"
     
     
def​ measure(&block)
     
  no_gc = (ARGV[0] == ​"--no-gc"​)
     
     
  ​if​ no_gc
     
    GC.disable
     
  ​else
     
    ​# collect memory allocated during library loading
     
    ​# and our own code before the measurement
     
    GC.start
     
  ​end
     
     
  memory_before = `ps -o rss= -p #{Process.pid}`.to_i/1024
     
  gc_stat_before = GC.stat
     
  time = Benchmark.realtime ​do
     
    ​yield
     
  ​end
     
  puts ObjectSpace.count_objects
     
  ​unless​ no_gc
     
    GC.start(full_mark: true, immediate_sweep: true, immediate_mark: false)
     
  ​end
     
  puts ObjectSpace.count_objects
     
  gc_stat_after = GC.stat
     
  memory_after = `ps -o rss= -p #{Process.pid}`.to_i/1024
     
     
  puts({
     
    RUBY_VERSION => {
     
      gc: no_gc ? ​'disabled'​ : ​'enabled'​,
     
      time: time.round(2),
     
      gc_count: gc_stat_after[:count] - gc_stat_before[:count],
     
      memory: ​"%d MB"​ % (memory_after - memory_before)
     
    }
     
  }.to_json)
     
end