lib/memory_profiler.rb
# Taken from
# http://scottstuff.net/blog/2006/08/17/memory-leak-profiling-with-rails
# This is useful for finding memory leaks of the sort where a reference has
# been accidentally kept to an object when it wasn't intended to be. It
# is particularly useful if the leaking objects contain strings.
#
# You can enable it in config/environments/development.rb It then writes
# to log files in logs/memory_profiler*
#
# If you have :string_debug enabled, you might find this one liner useful. It
# compares the two most recent string dumps.
# strings `ls -1t *profiler_strings* | head --lines=1` |sort > a; strings `ls -1t *profiler_strings* | head --lines=2 | tail --lines=1` |sort > b; diff b a |less
class MemoryProfiler
DEFAULTS = { delay: 10, string_debug: false }
def self.start(opt={})
opt = DEFAULTS.dup.merge(opt)
Thread.new do
prev = Hash.new(0)
curr = Hash.new(0)
curr_strings = []
delta = Hash.new(0)
file = File.open('log/memory_profiler.log','w')
loop do
begin
GC.start
curr.clear
curr_strings = [] if opt[:string_debug]
ObjectSpace.each_object do |o|
curr[o.class] += 1 #Marshal.dump(o).size rescue 1
curr_strings.push o if opt[:string_debug] && (o.class == String)
end
if opt[:string_debug]
File.open("log/memory_profiler_strings.log.#{Time.now.to_i}",'w') do |f|
curr_strings.sort.each do |s|
f.puts s
end
end
curr_strings.clear
end
delta.clear
(curr.keys + delta.keys).uniq.each do |k,_v|
delta[k] = curr[k]-prev[k]
end
file.puts "Top 20"
delta.sort_by { |_k,v| -v.abs }[0..19].sort_by { |_k,v| -v }.each do |k,v|
file.printf "%+5d: %s (%d)\n", v, k.name, curr[k] unless v == 0
end
file.flush
delta.clear
prev.clear
prev.update curr
GC.start
rescue Exception => err
$stderr.puts "** memory_profiler error: #{err}"
end
sleep opt[:delay]
end
end
end
end