Find the memory overhead of threads in Ruby

thread_memory_overhead.rb

def memory_kb
  `ps -o rss= -p #{Process.pid}`.chomp.to_i
end

MEM_LOG = "current memory: %{mem} kB (+%{incr})".freeze
THR_LOG = "New Thread!".freeze

current_mem = 0
loop do
  m = memory_kb()
  puts MEM_LOG % { mem: m, incr: m - current_mem }
  current_mem = m

  Thread.new do
    puts THR_LOG
    sleep 10_000
  end

  sleep 1
end