Class: MemoryProfiler

Inherits:
Object
  • Object
show all
Defined in:
lib/memory_profiler.rb

Overview

This is a memory profiler for Ruby. Once started, it runs in a thread in the background, periodically inspecting Ruby’s ObjectSpace to look for new objects and printing a count of objects added and removed since the previous cycle.

To use the profiler, do something like this:

require 'memory_profiler'

MemoryProfiler.start

The profiler will write logs to ./log/memory_profiler.log.

If you start MemoryProfiler with the ‘:string_debug => true’ option, then it will dump a list of all strings in the app into the log/ directory after each cycle. You can then use ‘diff’ to spot which strings were added between runs.

Constant Summary collapse

DEFAULTS = 
{:delay => 10, :string_debug => false}

Class Method Summary collapse

Class Method Details

.start(opt = {}) ⇒ Object 



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# File 'lib/memory_profiler.rb', line 21

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.#{Time.now.to_i}.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
          if opt[:string_debug] and o.class == String
            curr_strings.push o
          end
        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: #{Time.now}"
        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