Prints memory and cpu footprint of the server (uses ps in a subshell)

print_resource_usage.rb

module Kernel
  # Prints memory and cpu footprint of the server (uses ps in a subshell,
  # portability is therefore limited)
  def print_resource_usage
    ps_out = `ps -o vsz,rss,%cpu,%mem -p #{$$}`
    vsz, rss, cpu, pmem = ps_out.scan(/\d+(?:[.,]\d+)?/).map { |e| e.gsub(/,/,'.').to_f } # ps on 10.5.1 outputs ',' instead of '.' for MEM%
    virtual, real = (vsz-rss).div(1024), rss.div(1024)
    $stdout.printf "%dMB real, %dMB virtual, %.1f%% CPU, %.1f%% MEM\n", real, virtual, cpu, pmem
  end
  module_function :print_resource_usage
end