smaps pss memory usage

memory.rb

#!/usr/bin/env ruby

require 'process/pipeline'

def process_group_pids(pids)
	pids.flat_map do |pid|
		buffer = Process::Pipeline.("pstree -p #{pid}").read
		
		buffer.scan(/(?<=\()\d+(?=\))/)
	end.sort.uniq
end

usage = Hash.new{|h,k| h[k] = 0}

pids = process_group_pids(ARGV.map(&:to_i))

pids.each do |pid|
	smaps = File.readlines("/proc/#{pid}/smaps")
	
	smaps.each do |line|
		if /(?<key>.*?):\s+(?<value>\d+) kB/ =~ line
			usage[key] += value.to_i
		end
	end
end

usage.each do |key, value|
	next if value.zero?
	
	puts "#{key}: #{(value / 1024.0).round(2)}Mb"
end