added sample unicorn config

added utility to measure real memory usage
don't require thin by default

script/memstats.rb

@@ -0,0 +1,136 @@
+#!/usr/bin/env ruby
+# from: https://gist.github.com/kenn/5105061/raw/ac7ebc6be7008c35b72560cc4e05b7cc14eb4919/memstats.rb
+
+#------------------------------------------------------------------------------
+# Aggregate Print useful information from /proc/[pid]/smaps
+#
+# pss  - Roughly the amount of memory that is "really" being used by the pid
+# swap - Amount of swap this process is currently using
+#
+# Reference:
+#  http://www.mjmwired.net/kernel/Documentation/filesystems/proc.txt#361
+#
+# Example:
+#   # ./memstats.rb 4386
+#   Process:             4386
+#   Command Line:        /usr/bin/mongod -f /etc/mongo/mongod.conf
+#   Memory Summary:
+#     private_clean             107,132 kB
+#     private_dirty           2,020,676 kB
+#     pss                     2,127,860 kB
+#     rss                     2,128,536 kB
+#     shared_clean                  728 kB
+#     shared_dirty                    0 kB
+#     size                  149,281,668 kB
+#     swap                    1,719,792 kB
+#------------------------------------------------------------------------------
+
+class Mapping
+  FIELDS = %w[ size rss shared_clean shared_dirty private_clean private_dirty swap pss ]
+  attr_reader :address_start
+  attr_reader :address_end
+  attr_reader :perms
+  attr_reader :offset
+  attr_reader :device_major
+  attr_reader :device_minor
+  attr_reader :inode
+  attr_reader :region
+
+  attr_accessor :size
+  attr_accessor :rss
+  attr_accessor :shared_clean
+  attr_accessor :shared_dirty
+  attr_accessor :private_dirty
+  attr_accessor :private_clean
+  attr_accessor :swap
+  attr_accessor :pss
+
+  def initialize( lines )
+
+    FIELDS.each do |field|
+      self.send("#{field}=", 0)
+    end
+
+    parse_first_line( lines.shift )
+    lines.each do |l|
+      parse_field_line(l)
+    end
+  end
+
+  def parse_first_line( line )
+    parts = line.strip.split
+    @address_start, @address_end = parts[0].split("-")
+    @perms = parts[1]
+    @offset = parts[2]
+    @device_major, @device_minor = parts[3].split(":")
+    @inode = parts[4]
+    @region = parts[5] || "anonymous"
+  end
+
+  def parse_field_line( line )
+    parts = line.strip.split
+    field = parts[0].downcase.sub(':','')
+    if respond_to? "#{field}="
+      value = Float(parts[1]).to_i
+      self.send( "#{field}=", value )
+    end
+  end
+end
+
+def consume_mapping( map_lines, totals )
+  m = Mapping.new( map_lines )
+
+  Mapping::FIELDS.each do |field|
+    totals[field] += m.send( field )
+  end
+  return m
+end
+
+abort 'usage: memstats [pid]' unless ARGV.first
+pid = ARGV.shift.to_i
+totals = Hash.new(0)
+mappings = []
+
+File.open( "/proc/#{pid}/smaps" ) do |smaps|
+
+  map_lines = []
+
+  loop do
+    break if smaps.eof?
+    line = smaps.readline.strip
+    case line
+    when /\w+:\s+/
+      map_lines << line
+    when /[0-9a-f]+:[0-9a-f]+\s+/
+      if map_lines.size > 0 then
+        mappings << consume_mapping( map_lines, totals )
+      end
+      map_lines.clear
+      map_lines << line
+    else
+      break
+    end
+  end
+end
+
+# http://rubyforge.org/snippet/download.php?type=snippet&id=511
+def format_number( n )
+  n.to_s.gsub(/(\d)(?=\d{3}+(?:\.|$))(\d{3}\..*)?/,'\1,\2')
+end
+
+def get_commandline( pid )
+  commandline = IO.read( "/proc/#{pid}/cmdline" ).split("\0")
+  if commandline.first =~ /java$/ then
+    loop { break if commandline.shift == "-jar" }
+    return "[java] #{commandline.shift}"
+  end
+  return commandline.join(' ')
+end
+
+
+puts "#{"Process:".ljust(20)} #{pid}"
+puts "#{"Command Line:".ljust(20)} #{get_commandline(pid)}"
+puts "Memory Summary:"
+totals.keys.sort.each do |k|
+  puts "  #{k.ljust(20)} #{format_number( totals[k] ).rjust(12)} kB"
+end