Script find usage of shared libraries of a running process

mem-usage.rb

#!/usr/bin/env ruby

# filename="/proc/5952/maps"

def usage
  puts "USAGE: #{$0} /proc/<pid>/maps"
  exit
end

filename=ARGV[0]
usage unless filename

libs = {}

File.open(filename).readlines.each do |line|
  entries = line.split(/\s+/)
  # p [ entries, entries.size]
  if entries.size == 6 then
    libname = entries[-1]
    if libname =~ /\.so/ then
      start_mem,to_mem = entries[0].split("-")
      bytes = to_mem.hex - start_mem.hex
      # puts "#{libname}: #{bytes/1024.0} KBs"
      if libs[libname] then
        old_val = libs[libname]
        new_val = (old_val || 0) + bytes
        libs[libname] = new_val
      else
        libs[libname] = bytes
      end
    end
  end
end

total = 0
libs.keys.sort.each do | k |
  libname = k
  bytes = libs[k]
  puts "#{libname}: #{bytes/1024.0} KBs"
  total += bytes
end

puts "total memory consumption by shared libraries: #{total/1024.0} KBs ( #{total/1024.0/1024} MBs )"