Memory profiler tools for ruby

Memory profiler tools for ruby It so happened that I was need know how much ruby objects created for each call sidekiq perform_async method (mperham/sidekiq#2288). That’s why I decided to create list with tools which helps you to know all required information.

1. Ruby GC

Sam Saffron has written great post, in which he talk about ruby garbage collector and wonderful GC.start method which returns data hash:

2.2.0:001 > GC.stat
# => {:count=>21, :heap_allocated_pages=>236, :heap_sorted_length=>237, :heap_allocatable_pages=>0, :heap_available_slots=>96193, :heap_live_slots=>95354, … }

Also author mentions a ObjectSpace module that lets you know information about object/memory management. For example you can easily know general number of created objects. For this you need write this code:

2.2.0:002 > ObjectSpace.count_objects[:TOTAL]
# => 96193

2. Ruby Memory Profiler

Also Sam wrote great tool (ruby-memory-profiler) which provide easily display all required information for any code in block. For this you will need call something like this (I called this code in my sidekiq reduce allocation PR):

MemoryProfiler.report{ 100.times{ HardWorker.perform_async } }.pretty_print

3. ruby-prof

General features:

• display different reports;
• fast;
• easily profiles rails apps;

How to use:

require 'ruby-prof'

# Profile the code
RubyProf.start
# [code to profile]
RubyProf.pause
# [other code]
RubyProf.resume
# [code to profile]
result = RubyProf.stop

Conclusions

Profiling Ruby isn’t as difficult as it seems at first glance. There are a lot of great libraries. The only thing I was missing — profiling the code from a file, but I’m sure it will soon add (maybe it will add myself ☺ ).