Ruby Under The Hood
- 1. About me 1 Guelph ES&C Grad – spring 2014 Currently employed at IBM as a Runtime Technologies Software Dev Twitter: @craiglehmann
- 2. Ruby Under The Hood http://lolsnaps.com/upload_pic/EveryTimeILookUnderThe HoodOfACar-97946.jpg
- 6. Program compilation 6 3.times do |n| puts n end
- 7. Program compilation 7 Tokens: 3.times do |n| puts n end puts ndo end 3 dot times
- 8. Program compilation 8 AST 3.times do |n| puts n end puts n 3 times call block command
- 10. The Ruby Interpreter? The Ruby Interpreter implements a virtual machine. 10
- 11. Bytecode Interpreter The main VM execution loop. Maps bytecodes to executable native instructions. Implements a virtual stack machine. Individual bytecodes implemented in C. 11
- 12. 12 Ruby is a Stack Machine!
- 13. Push Down Stack 13 1 + 2
- 14. Push Down Stack 14 1 + 2 Push 1 Push 2 opt_plus Bytecodes:
- 15. Push Down Stack 15 1 + 2 Push 1 Push 2 opt_plus Bytecodes: 1 Push 1
- 16. Push Down Stack 16 1 + 2 Push 1 Push 2 opt_plus Bytecodes: 1 Push 1 2 Push 2 1
- 17. Push Down Stack 17 1 + 2 Push 1 Push 2 opt_plus Bytecodes: 1 Push 1 2 Push 2 3 opt_plus 1
- 18. Call Stack example and compiled method 18 def do_things puts "Hello World" end Putself Putstring “Hello World” opt_send_simple
- 19. Three Stacks 19 def do_things puts "Hello World" end Putself Putstring “Hello World” opt_send_simple C Stack VM Stack Ruby Call Stack
- 20. Call Stack example and compiled method 20 def do_things puts "Hello World" end Putself Putstring “Hello World” opt_send_simple call_method C Stack exec_core … main() VM Stack Ruby Call Stack
- 21. Call Stack example and compiled method 21 def do_things puts "Hello World" end Putself Putstring “Hello World” opt_send_simple call_method C Stack exec_core … main() opt_send_simple puts VM Stack “hello World” self Ruby Call Stack
- 22. Call Stack example and compiled method 22 def do_things puts "Hello World" end Putself Putstring “Hello World” opt_send_simple call_method C Stack exec_core … main() opt_send_simple puts VM Stack “hello World” self puts Ruby Call Stack do_things
- 23. Three Stacks 23 call_method C Stack exec_core … main() opt_send_simple puts VM Stack “hello World” self puts Ruby Call Stack do_things
- 24. What does this look like in the Ruby’s VM? 24 puts Ruby Call Stack do_things def do_things puts "Hello World" end
- 25. What does this look like in the Ruby’s VM? 25 puts Ruby Call Stack do_things def do_things puts "Hello World" end PC Control Frame SP Self type
- 26. What does this look like in the Ruby’s VM? 26 puts Ruby Call Stack do_things def do_things puts "Hello World" end PC Control Frame SP Self type putself putstring “Hello World” opt_send_simple
- 27. What does this look like in the Ruby’s VM? 27 puts Ruby Call Stack do_things def do_things puts "Hello World" end PC Control Frame SP Self type putself putstring “Hello World” opt_send_simple opt_send_simple puts VM Stack “hello World” self
- 28. Class lookup? What happens when you want to create an object? 28 class Person end p = Person.new()
- 29. Class lookup? What happens when you want to create an object? 29 class Person end p = Person.new()
- 30. Class lookup? What happens when you want to create an object? 30 class Person end p = Person.new() Person = "Craig" #Warning: already initialized constant person
- 31. Intro to garbage collection What is garbage collection? Different types of garbage collection algorithms Mark & Sweep demo 31
- 32. 32 What is garbage collection? Automatic memory management Manually managing memory is hard! Aggregate freeing memory & object destruction operations Gives the illusion of unlimited memory
- 33. 33 Different types of garbage collection algorithms Reference Counting • Keep a count along with each object indicating how many references it currently has. An object with 0 references can have it's memory re-used. • Cannot manage cyclically referenced objects. Tracing Algorithms • keep track of which objects are in use by recursively tracing objects referring to other objects, starting from a root set of objects.
- 34. What does it mean to die • An object consumes one resource, memory. • When an object becomes unreachable, it can never be used again. • Cycles are collected together, the mutator cannot access these object. • Sweeping objects means adding it’s memory to a list for reuse. • What about when an object consumes more than just one resource? 34
- 35. Mark and Sweep Demo 35
- 36. Mark and Sweep Demo 36
- 37. Mark and Sweep Demo 37
- 38. Mark and Sweep Demo 38
- 39. Mark and Sweep Demo 39
- 40. Mark and Sweep Demo 40
- 41. Mark and Sweep Demo 41
- 42. Mark and Sweep Demo 42
- 43. Object Finalization • Some objects may have operations that need to occur pre/post collection • e.g. file object 43
- 44. Execution Environment Architecture of a Managed Runtime 44 Platform Abstraction Layer Garbage Collector Diagnostic Services Source Code Bytecode/AST Compiler Just-In-Time Compiler Interpreter
- 45. Execution Environment Architecture of a Managed Runtime 45 Platform Abstraction Layer Garbage Collector Diagnostic Services Source Code Bytecode/AST Compiler Just-In-Time Compiler Interpreter
- 46. Execution Environment Architecture of a Managed Runtime 46 Platform Abstraction Layer Garbage Collector Diagnostic Services Source Code Bytecode/AST Compiler Just-In-Time Compiler Interpreter
- 47. Execution Environment Architecture of a Managed Runtime 47 Platform Abstraction Layer Garbage Collector Diagnostic Services Source Code Bytecode/AST Compiler Just-In-Time Compiler Interpreter Interpreter context Thread context Language callstack
- 48. Execution Environment Architecture of a Managed Runtime 48 Platform Abstraction Layer Garbage Collector Diagnostic Services Source Code Bytecode/AST Compiler Just-In-Time Compiler Interpreter
- 49. Execution Environment Architecture of a Managed Runtime 49 Platform Abstraction Layer Garbage Collector Diagnostic Services Source Code Bytecode/AST Compiler Just-In-Time Compiler Interpreter
- 50. Execution Environment Architecture of a Managed Runtime 50 Platform Abstraction Layer Garbage Collector Diagnostic Services Source Code Bytecode/AST Compiler Just-In-Time Compiler Interpreter
- 51. Thank You! Twitter: @craigLehmann Email: craigl@ca.ibm.com