A Tool of the Future
aka the road to enlightenment
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Ask/give questions/comments.
Both nice and nasty.

Mantra of rubinius
If it can be done in ruby, then it shouldn’t be in C.
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An idealist is a person who helps
other people to be prosperous.
Henry Ford

the edges of the sword are life and death
no one knows which is which
Ikkyū Sōjun

If you’re not failing every now
and again, it’s a sign you’re not
anything very innovative.
Woody Allen

KHAAAAANN!
James T. Kirk

• What is (and is not) rubinius?
• Who is rubinius?
• Features and Goals
• Timeline
• Technical Details
• Demo / Questions
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http://rubini.us

What.
• A brand new ruby engine
• Bytecode Virtual Machine based
• Generational Garbage Collection
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Why.
• Fun
• A desire for a better interpreter
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Why pt. 2
• Every talk at this conference has mentioned
some limitation of ruby.
• All limitations are limitations of the current
interpreter, not the language.
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What it’s not.
• Vaporware
• A thesis project
• Finished.
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Who.
• Aki Reijonen (loop)
Evan Phoenix (evan)
• Mat Elder (mae)
Brian Ford (brixen)
• John Hornbeck (hornbeck)
Wilson Bilkovich (Defiler)
• Carsten Bormann (cabo)
Pat Eyler (pate)
• Devin Walters (defn)
Alan Hurdle (hurdlea)
• Frederick Ros (sleeper)
Thomas Lockney (tlockney)
• Alexander Kellet (lypanov)
Eero Saynatkai (rue)
• Mikko Lehtonen (scoopr)
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Features and Goals
• Remember the Mantra!
• VM in C only
• Includes primitive operations
• Extensive tests and specs
• Core library in ruby
• Array#dup, Method#new, Object#instance_eval
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• 1.8.5 compatible
• 98% first class
• Easy to understand, easy to extend, easy to
optimize
• MRI (Matz Ruby Interpreter) C API compatible
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Timeline.
• 1.0 by October, 2007 - RubyConf
• Near 100% compatible with 1.8.5
• Able to run rails 1.2
• 2.0
• JIT
• Optimizers
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Technical Details
• 5 core sections
• CPU
• Primitives
• Compiler
• Object Memory / Garbage Collection
• Core library
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CPU
• Fully bytecode based
• All bytecodes are written test first
• Leverage GCC to make help make fast
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Threads
• Currently supports green threads
• Contains low level sychronization / sharing
mechanism called Channel
• A PI Calculus-like channel
• Native Thread support in a MxN scheme
• (eventually)
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Primitives
• The most basic method
• Written C (for now)
• Provide most basic functionality
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Compiler
• Completely written in ruby
• COMPLETELY WRITTEN IN RUBY
• Self bootstrapped from initial rubinius
prototype
• Pipeline based architecture
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# rbx sirb -p -s -b
sirb(eval):000> puts “hello evan”

puts "hello evan"

[:newline, 1,
"(eval)",
[:fcall, :puts,
[:array, [:str, "hello evan"]]]]

#line 1
push_literal 0
string_dup
push self
send puts 1
ret

"v00000000:fC0000
0000)000000010000
0001'0000"

• Every stage is directly accessible
• Think: new parsers that output rubinius
assembly
• LISP
• Smalltalk
• Erlang
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• Compiler is a normal class, which open doors...
• Compile ERB templates directly into
CompiledMethods
• Ability to remove Kernel#eval if an
application of rubinius warrants it
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“The Reaper”
(Object Memory / Garbage Collection)
• Generational Collector
• Young Objects: Baker two-space compacting
collector
• Mature Objects: Mark/Sweep collector
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Infanticide
• Young objects live fast and die young (usually)
• Once an object survives for a while, it’s
promoted to the mature object space.
• Compaction keeps the memory footprint small.
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The Old Guard
• Mature objects are collected 10 to 30 times
less often than young objects.
• All object access in VM is done through the
“write barrier”, which maintains the set of
mature objects that reference young objects.
• Objects themselves are not marked, making
rubinius very “fork friendly”.
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Core library
• Everything you’ve come to love, now in written
in ruby.
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def [](arg, len = nil)
if len
len = len.to_i
return nil if len < 0
end
if arg.is_a? String
unless len.nil?
raise ArgumentError.new("String#[] cannot accept a second argument with a String.")
end
return (self.include?(arg) ? arg.dup : nil)
elsif arg.respond_to? :match
m = arg.match(self)
return m[len.to_i] if m && len
return m[0] if m
return nil
elsif arg.respond_to?(:first) and arg.respond_to?(:last)
from = arg.first
to = arg.last
to -= 1 if arg.respond_to?(:exclude_end?) && arg.exclude_end?
size = self.size
from = from + size if from < 0
to += size if to < 0
len = to - from + 1
self[from, len]
elsif arg and arg.respond_to?(:to_i)
arg = arg.to_i
String#[]
size = self.size
arg = arg + size if arg < 0
if 0 <= arg && arg < size
if len
len = size - arg if arg + len >= size
substring(arg, len)
else
@data[arg]
end
else # invalid start index
len ? "" : nil
end
else
raise ArgumentError.new("String#[] cannot accept #{arg.class} objects")
end

def parent
a=3
ask_child(a)
puts "OMG #{a} PONIES!"
end
def ask_child(initial_pony_count)
ctx = MethodContext.current.sender
# Will be ctx.locals[:a] = 9 soon.
ctx.locals[2] = 9
end
parent()

OMG 9 PONIES!

Nothing is sacred.
(evil built in)

Backtraces
vatu :: rbx-branches/event> ./shotgun/rubinius ctx.rb
An exception has occured:
No method 'ask_child' on an instance of Object. (NoMethodError)
Backtrace:
NoMethodError#initialize at core/exception.rb:47
NoMethodError.new at bootstrap/class.rb:8
main.ask_child (method_missing) at bootstrap/method_missing.rb:8
main.parent at ctx.rb:3
main.__script__ at ctx.rb:12
main.load at core/compile.rb:56
main.__script__ at core/__loader.rb:95
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MethodTables
class Blah
end
class Foo
def hello
puts “hello evan”
end
end
Blah.methods[:hello_also] = Foo.methods[:hello]
Blah.new.hello_also # hello evan
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It’s your party.
class Mu < nil
end
p Mu.instance_methods # []
p Mu.superclass # nil
you still mad? 41

Zen and the Art of Object Creation
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VM level Sampler
s = Sampler.new(100) # 100 hz
s.start
100000.times { 1 + 1 }
s.stop
s.results.size # 332
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CompiledMethods
m = Array.methods[:index]
p m # #<CompiledMethod:0x32a34 ...>
p m.name # :index
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But what does that all mean?!

We all know and love
introspection, so take that to the
next level...

• Better debbugers
• Read MethodContext objects directly
• Richer information
• Read method cache’s to find out common
classes for arguments and locals
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A Better Tool.

!=

How you can help
• Write tests / specs
• Write core library functionality
• Write VM code
• Port valgrind to OS X
• Bounty available!
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Evan Phoenix
http://rubini.us
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