This is a short introduction to Rubinius along with detailed introduction to heap dump analysis using Rubinius.

1. Rubinius
Ruby Implemented with Ruby

2. About us
● Graduated from COEP (IT) in 2014
● Rails Girls Summer of Code, 2014 Interns
● http://teamrubiniusrgsoc14.blogspot.in/
● @AkankshaHA, @sanakhan_libre

3. Agenda
● What is Rubinius?
● Components
● Flow of Ruby Code to Machine Code
● Implementation of basic methods
● Backtraces
● Various tools
● Heap Dump Interface
● Metrics
● New Features in Rubinius 3.0

4. ● An alternative implementation of Ruby interpreter
● Started in 2006 by Evan Phoenix with an objective to implement Ruby in
Ruby
What is Rubinius?

5. Components
● Kernel (Ruby)
Definition of built-in classes (rubinius/kernel/common)
● Virtual Machine (C++)
GC
JIT Compiler (LLVM)
Additional code for built-in classes (rubinius/vm)

6. Source: Ruby Under a Microscope, Pat Shaughnessy

7. Ruby to Machine Code
Parsing (Melbourne)
Compilation (Ruby Code)
JIT Compilation (C++)
Machine Code
Ruby
Interpretation (VM)
AST Nodes
Rubinius Instructions
(Bytecode)
LLVM Instructions

8. Digging into Rubinius Code

9. String#upcase!

11. String#allocate

12. Array#shift

14. Examining Tuple#at

16. Backtraces in Rubinius vs MRI

17. Backtrace in Ruby

18. Backtrace in Rubinius

19. Rubinius Tools
● Debugger
● Profiler
● Heap Dump Interface
● Metrics
● And more..
● Tools in Rubinius 3.0
http://rubini.us/2014/11/13/rubinius-3-0-part-4-the-system-and-tools

20. The Rubinius Heap Dump Interface

21. What are heap dumps used for?
● Heap dumps is one of the most important analysis tools.
● Analyzing memory footprint of applications.
● Detecting Memory Leaks
● Identifying root cause of Memory Leaks

22. What is a heap dump?
Heap dump is a snapshot
of memory of a particular
process running at that
instant of time.

23. Obtaining Binary Heap Dump
● Rubinius::VM.dump_heap('/path/to/the/file.dump')
Or
● Via the Query Agent

24. A Sample Leaky Program

25. Histogram Representation

26. Diff of two heap snapshots

27. Per Class Statistics

33. Rubinius Metrics
● Accessible using Rubinius::Metrics.data
● Directly emitted to StatsD
●
● Metrics - StatsD - InfluxDB - Grafana
● http://rubini.us/2014/12/10/rubinius-metrics-meets-influxdb/

34. Metrics in Grafana dashboard

35. Some more metrics..

36. New features in Rubinius 3.0
● JIT compiler code to be written in Ruby, JIT Planner
● CodeDB
● Rubinius::Console

37. Questions?