The FUTURE of
Tuesday, September 17, 13
Me
• Charles Oliver Nutter
• @headius
• Java developer since 1996
• JRuby developer since 2006
• Red Hat / JBoss polyglot ...
Have you heard of
JRuby?
Tuesday, September 17, 13
Have you tried
JRuby?
Tuesday, September 17, 13
Are you using
JRuby?
Tuesday, September 17, 13
What is JRuby?
Tuesday, September 17, 13
Ruby on the JVM
Tuesday, September 17, 13
Ruby on the JVM
I don't like Java so I don'tlike JRuby
Tuesday, September 17, 13
Ruby on the JVM
I don't like Java so I don'tlike JRuby
LOL applets
Tuesday, September 17, 13
Ruby on the JVM
JVM SUCKS ROFL
I don't like Java so I don'tlike JRuby
LOL applets
Tuesday, September 17, 13
Ruby on the JVM
JVM SUCKS ROFL
AbstractMetaRubyImplementationFactoryFactoryImpl
I don't like Java so I don'tlike JRuby
LOL...
Welcome to Spain
Tuesday, September 17, 13
Welcome to Spain
Tuesday, September 17, 13
Welcome to Spain
Tuesday, September 17, 13
Welcome to Spain
Tuesday, September 17, 13
Welcome to Spain
Tuesday, September 17, 13
Welcome to Spain
Tuesday, September 17, 13
Welcome to Spain
Tuesday, September 17, 13
JRuby is Ruby!!!
on the JVM... shhh!
Tuesday, September 17, 13
The Basics
• Compatible with Ruby 1.8.7, 1.9.3
• Mostly written in (clean) Java
• More and more in Ruby going forward
• En...
Roadmap
1.6.0
1.6.1
1.6.2 1.6.3 1.6.7.2
1.7.0.pre1
1.6.4
...
1.6.8
...
1.7.3 1.7.4 1.7.5
1.7.6
...
9000!
Next week or two
...
JRuby 9000 really is the
next version...
9k
...Coming 2014
Tuesday, September 17, 13
One point release
later...
Tuesday, September 17, 13
9K Questions
• Ruby 2.0 or 2.1-only?
• 1.8 support gone
• 1.9 support gone
• Java 7+ only?
• New compiler will be... ?
Tue...
Why JRuby?
Tuesday, September 17, 13
JRuby Team
Tuesday, September 17, 13
JRuby Team
Charlie
Tuesday, September 17, 13
JRuby Team
Charlie Tom
Nick Hiro Marcin Nahi Wayne Subbu DouglasDouglasContribsDouglas
Tuesday, September 17, 13
JRuby Team
Charlie Tom
Nick Hiro Marcin Nahi Wayne Subbu DouglasDouglasContribs
DouglasDouglasOpenJDK
DouglasDouglasAndroi...
JVM Over Time
0
7.5
15
22.5
30
Java 1.4 Java 5 Java 6 Java 7
JRuby 1.0.3 (bm_red_black_tree.rb)
Tuesday, September 17, 13
Versus MRI 1.8
0
7.5
15
22.5
30
Java 1.4 Java 5 Java 6 Java 7
JRuby 1.0.3 (bm_red_black_tree.rb) MRI 1.8
Tuesday, Septembe...
0ms
75ms
150ms
225ms
300ms
188KB/29MB 27MB/127MB 199MB/238MB
Time per GC versus heap usage
TimeperGC
Heap usage (MRI/JRuby...
Features Over Time
1.6 1.8.4 1.8.6 1.8.7 1.9.2 1.9.3 2.0 2.1
Ruby Features
JRuby Support
Tuesday, September 17, 13
However...
• JVM development is not fast
• JRuby must move forward
• Constantly improving
Tuesday, September 17, 13
What could be better?
Performance
Native Extensions
Concurrency
Startup Time
Tuesday, September 17, 13
Performance
Tuesday, September 17, 13
Hard to Optimize
• Dynamic calls with lots of overhead
• Dynamic object structure with indirection
• Lots and lots of obje...
Solutions
Tuesday, September 17, 13
Compile to Bytecode
• JVM likes JVM bytecode (surprise!)
• Simple compilation of Ruby
• Let JVM do the work
• Can we do be...
Invokedynamic
• New JVM feature for languages
• Bytecode + IR to describe calls
• JVM patches straight through
• Optimize ...
Tuesday, September 17, 13
0 1 2 3 4
ruby-1.9.3 + Ruby
ruby-2.0.0 + Ruby
maglev + Ruby
macruby-0.12 + Ruby
rbx-2.0.0rc1 + Ruby
ruby-1.9.3 + C ext
rub...
0 1 2 3 4
ruby-1.9.3 + Ruby
ruby-2.0.0 + Ruby
maglev + Ruby
macruby-0.12 + Ruby
rbx-2.0.0rc1 + Ruby
ruby-1.9.3 + C ext
rub...
0 1 2 3 4
ruby-1.9.3 + Ruby
ruby-2.0.0 + Ruby
maglev + Ruby
macruby-0.12 + Ruby
rbx-2.0.0rc1 + Ruby
ruby-1.9.3 + C ext
rub...
0 1 2 3 4
ruby-1.9.3 + Ruby
ruby-2.0.0 + Ruby
maglev + Ruby
macruby-0.12 + Ruby
rbx-2.0.0rc1 + Ruby
ruby-1.9.3 + C ext
rub...
0 1 2 3 4
ruby-1.9.3 + Ruby
ruby-2.0.0 + Ruby
maglev + Ruby
macruby-0.12 + Ruby
rbx-2.0.0rc1 + Ruby
ruby-1.9.3 + C ext
rub...
But...
• Indy was really slow in first Java 7 release
• Got fast in 7u2...and turned out broken
• Rewritten for 7u40
• Slow...
Other Options
• New IR compiler/runtime in 9k
• Optimize Ruby code before JVM
• Specialize types, elide allocations
Tuesda...
Lexical
Analysis
Parsing
Semantic
Analysis
Optimization
Bytecode
Generation
Interpret
AST
IR Instructions
CFG DFG ...
Exis...
1 check_arity(2, 0, -1)
2 a(0:0) = recv_pre_reqd_arg(0)
3 thread_poll
4 line_num(2)
5 %v_2 = call(+, a(0:0), [1:Fixnum])
6...
Other Options
• Truffle/Graal
• New compiler backends from Oracle
• Graal = direct API to native JIT
• Truffle = magic optim...
The Hard Part
{
Tuesday, September 17, 13
Sooo....
• Keep working with JVM guys on InDy
• Get our own optimizing compiler done
• Explore Graal/Truffle backend
• Comp...
Concurrency
Tuesday, September 17, 13
True Parallellism
Ruby
Threads
Native
Threads
Ruby 1.8.7 Ruby 2.0.0
Green Threading
CPU Cores
in Use
JRuby
Global LockSing...
Multicore in MRI
200MB MRI
Instance
200MB MRI
Instance
200MB MRI
Instance
200MB MRI
Instance
200MB MRI
Instance
200MB MRI
...
Multicore in MRI
200MB MRI
Instance
200MB MRI
Instance
200MB MRI
Instance
200MB MRI
Instance
200MB MRI
Instance
200MB MRI
...
Multicore in JRuby
300MB JRuby
Instance
One instance across 10 threads = 300MB
Tuesday, September 17, 13
Multicore in JRuby
300MB JRuby
Instance
One instance across 100 threads = 300MB
Tuesday, September 17, 13
But...
• Ruby world is still growing up
• Concurrency tools being created
• Libraries being made threadsafe
• We need to d...
Unsafe Operations
• Concurrent read+write on core structures
• Non-atomic updates
•@count +=1
•@cache ||= MyCache.new
• Th...
thread_safe
• Concurrency-safe Hash
• Concurrency-safe Array
require 'thread_safe'
sa = ThreadSafe::Array.new
sh = ThreadS...
hamster
• Persistent collections for Ruby
• A la Clojure and others
simon = Hamster.hash(:name => "Simon", :gender => :mal...
atomic
• Atomic value holder
• Safely update current value
• Edit value only if unchanged
• Full CPU-level atomicity guara...
require 'atomic'
my_atomic = Atomic.new(0)
my_atomic.value # => 0
my_atomic.value = 1
my_atomic.swap(2) # => 1
my_atomic.c...
jo
• Threaded implementation of "goroutines"
• "channel" for communication
Tuesday, September 17, 13
# pinger ponger printer
def pinger(c)
20.times { c << 'ping' }
end
def ponger(c)
20.times { c << 'pong' }
end
def printer(...
Bottom Line
• Concurrency can work in Ruby
• Use the right tools and patterns
• Immutability FTW
• Test your apps and libs...
Native Extensions
Tuesday, September 17, 13
Why Not Ruby?
• Performance
• Fine grained (lots of calls down to C)
• Coarse grained (toss work over the wall)
• Library ...
JRuby 1.6 C Exts
• Limited support (now disabled)
• Will be moved to external gem
• If you want it, support it
• Some stuf...
Problems
• Performance
• Data copying to emulate raw structs
• Locking to keep C code thread-safe
• Multiple JRuby instanc...
Alternatives
Tuesday, September 17, 13
Java Integration
• Call Java (Scala, Clojure, ...) from Ruby
• Smart mapping of method names
• Type conversions as appropr...
import javax.swing.JFrame
import javax.swing.JLable
frame = JFrame.new("Window")
label = JLabel.new("Hello")
frame.add(lab...
Java Native Extensions
• Similar to C ext for MRI, but with Java
• Fast call protocol...basically free
• Same GC for all o...
FFI
• Ruby API/DSL for calling native code
• Runs on all Ruby impls
• Maintained by JRuby team!
• Solves "access" use case...
Ruby FFI example
class Timeval < FFI::Struct
  layout :tv_sec => :ulong,
:tv_usec => :ulong
end
module LibC
  extend FFI::...
But...
• Struct binding issues
• Across OSes (also 32+64 bit archs)
• Across library versions
• Library compile option mis...
Ruby FFI Generator
• https://github.com/neelance/ffi-gen
• Clang-based Ruby FFI generator
• Used to generate clang binding ...
require "ffi/gen"
FFI::Gen.generate(
module_name: "Clang",
ffi_lib: "clang",
headers: ["clang-c/Index.h"],
cflags: `llvm-c...
  # A single translation unit, which resides in an index.
  class TranslationUnitImpl < FFI::Struct
    layout :dummy, :ch...
  # Retrieves the source location associated with a given file/line/column
  # in a particular translation unit.
  #
  # @...
XNI
• Ruby + plain old C
• Covers access and perf cases
• Cross-implementation support
• Struct mapping in compile phase
•...
hitimes C Ext
/**
* call-seq:
* interval.start -> boolean
*
* mark the start of the interval. Calling start on an already ...
hitimes XNI
/**
* call-seq:
* interval.start -> boolean
*
* mark the start of the interval. Calling start on an already st...
Startup Time
Tuesday, September 17, 13
#1 Pain Point
Tuesday, September 17, 13
Hard Problem
• MRI boot time is 95% native
• JRuby boot time is 0% native code
• Mostly Java, which needs to warm up
• Par...
Child Processes
• Reduce need for sub-Ruby invokes
• rails -> clean rails env in child
• rails/rake -> bundler relaunch
• ...
Lexical
Analysis
Parsing
Semantic
Analysis
Optimization
Bytecode
Generation
Interpret
AST
IR Instructions
CFG DFG ...
Exis...
Solutions
Tuesday, September 17, 13
Nailgun/Drip
• Always running background JVM
• Not quite production quality
• signals, IO
• Small Ruby scripts very fast
•...
GSoC 2012
IR Persistence
IR Instructions
CFG DFG ...
file.ir
file.rb
compile
file.c
compile
file.o
Tuesday, September 17, 13
Reflection on GSoC
• Size matters
• # of bytes
• Intern()‘ing of identifiers matter
• Laziness can help a lot
Tuesday, Septe...
Defined vs Used Methods
CMD DEFINED USED SAVINGS
-e ‘:foo’ 501 33 ~93%
gem install
rails
1897 529 ~72%
rails scaffold 9411 ...
New IR Persistence
• Binary format
• Constant pool to intern only once per id
• (currently once per occurrence)
• Incremen...
Ultimate Startup!
rails new foo
JRuby Instance
IR Data
rails generate
JRuby Instance
rake db:migrate
JRuby Instance
Compil...
Ruby is Strong
• Still growing and improving
• MRI too!
• Concurrency can be done
• C extensions are holding us back
• Nev...
ThankYou!
• Charles Oliver Nutter
• @headius
• headius@headius.com
• http://blog.headius.com
Tuesday, September 17, 13
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The Future of JRuby - Baruco 2013

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A talk on key areas of future work on JRuby, delivered at Baruco 2013 in Barcelona, Spain.

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  • I haven't heard the talk, i expect to. Because the slides 15 to 18 makes me wonder, without the talk I could easily mistake them as a confusion between Mexican and Spanish cultures, which are two different countries, related yet different. It is like confusing England with USA.
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The Future of JRuby - Baruco 2013

  1. 1. The FUTURE of Tuesday, September 17, 13
  2. 2. Me • Charles Oliver Nutter • @headius • Java developer since 1996 • JRuby developer since 2006 • Red Hat / JBoss polyglot group Tuesday, September 17, 13
  3. 3. Have you heard of JRuby? Tuesday, September 17, 13
  4. 4. Have you tried JRuby? Tuesday, September 17, 13
  5. 5. Are you using JRuby? Tuesday, September 17, 13
  6. 6. What is JRuby? Tuesday, September 17, 13
  7. 7. Ruby on the JVM Tuesday, September 17, 13
  8. 8. Ruby on the JVM I don't like Java so I don'tlike JRuby Tuesday, September 17, 13
  9. 9. Ruby on the JVM I don't like Java so I don'tlike JRuby LOL applets Tuesday, September 17, 13
  10. 10. Ruby on the JVM JVM SUCKS ROFL I don't like Java so I don'tlike JRuby LOL applets Tuesday, September 17, 13
  11. 11. Ruby on the JVM JVM SUCKS ROFL AbstractMetaRubyImplementationFactoryFactoryImpl I don't like Java so I don'tlike JRuby LOL applets Tuesday, September 17, 13
  12. 12. Welcome to Spain Tuesday, September 17, 13
  13. 13. Welcome to Spain Tuesday, September 17, 13
  14. 14. Welcome to Spain Tuesday, September 17, 13
  15. 15. Welcome to Spain Tuesday, September 17, 13
  16. 16. Welcome to Spain Tuesday, September 17, 13
  17. 17. Welcome to Spain Tuesday, September 17, 13
  18. 18. Welcome to Spain Tuesday, September 17, 13
  19. 19. JRuby is Ruby!!! on the JVM... shhh! Tuesday, September 17, 13
  20. 20. The Basics • Compatible with Ruby 1.8.7, 1.9.3 • Mostly written in (clean) Java • More and more in Ruby going forward • Entire world of JVM libraries available JVM JDK Classes Other Libraries JRuby Core Classes JRuby Runtime More Core Classes Standard Lib Extras Your Application FFI Tuesday, September 17, 13
  21. 21. Roadmap 1.6.0 1.6.1 1.6.2 1.6.3 1.6.7.2 1.7.0.pre1 1.6.4 ... 1.6.8 ... 1.7.3 1.7.4 1.7.5 1.7.6 ... 9000! Next week or two Tuesday, September 17, 13
  22. 22. JRuby 9000 really is the next version... 9k ...Coming 2014 Tuesday, September 17, 13
  23. 23. One point release later... Tuesday, September 17, 13
  24. 24. 9K Questions • Ruby 2.0 or 2.1-only? • 1.8 support gone • 1.9 support gone • Java 7+ only? • New compiler will be... ? Tuesday, September 17, 13
  25. 25. Why JRuby? Tuesday, September 17, 13
  26. 26. JRuby Team Tuesday, September 17, 13
  27. 27. JRuby Team Charlie Tuesday, September 17, 13
  28. 28. JRuby Team Charlie Tom Nick Hiro Marcin Nahi Wayne Subbu DouglasDouglasContribsDouglas Tuesday, September 17, 13
  29. 29. JRuby Team Charlie Tom Nick Hiro Marcin Nahi Wayne Subbu DouglasDouglasContribs DouglasDouglasOpenJDK DouglasDouglasAndroid DouglasDouglasJ9 DouglasDouglasOther JVMs Douglas Tuesday, September 17, 13
  30. 30. JVM Over Time 0 7.5 15 22.5 30 Java 1.4 Java 5 Java 6 Java 7 JRuby 1.0.3 (bm_red_black_tree.rb) Tuesday, September 17, 13
  31. 31. Versus MRI 1.8 0 7.5 15 22.5 30 Java 1.4 Java 5 Java 6 Java 7 JRuby 1.0.3 (bm_red_black_tree.rb) MRI 1.8 Tuesday, September 17, 13
  32. 32. 0ms 75ms 150ms 225ms 300ms 188KB/29MB 27MB/127MB 199MB/238MB Time per GC versus heap usage TimeperGC Heap usage (MRI/JRuby) Ruby 2.0.0 JRuby Tuesday, September 17, 13
  33. 33. Features Over Time 1.6 1.8.4 1.8.6 1.8.7 1.9.2 1.9.3 2.0 2.1 Ruby Features JRuby Support Tuesday, September 17, 13
  34. 34. However... • JVM development is not fast • JRuby must move forward • Constantly improving Tuesday, September 17, 13
  35. 35. What could be better? Performance Native Extensions Concurrency Startup Time Tuesday, September 17, 13
  36. 36. Performance Tuesday, September 17, 13
  37. 37. Hard to Optimize • Dynamic calls with lots of overhead • Dynamic object structure with indirection • Lots and lots of objects Tuesday, September 17, 13
  38. 38. Solutions Tuesday, September 17, 13
  39. 39. Compile to Bytecode • JVM likes JVM bytecode (surprise!) • Simple compilation of Ruby • Let JVM do the work • Can we do better? Tuesday, September 17, 13
  40. 40. Invokedynamic • New JVM feature for languages • Bytecode + IR to describe calls • JVM patches straight through • Optimize any kind of call like Java • Ruby as fast as Java...in theory Tuesday, September 17, 13
  41. 41. Tuesday, September 17, 13
  42. 42. 0 1 2 3 4 ruby-1.9.3 + Ruby ruby-2.0.0 + Ruby maglev + Ruby macruby-0.12 + Ruby rbx-2.0.0rc1 + Ruby ruby-1.9.3 + C ext ruby-2.0.0 + C ext jruby + Ruby jruby + Java ext red/black tree, pure Ruby versus native Runtime per iteration Tuesday, September 17, 13
  43. 43. 0 1 2 3 4 ruby-1.9.3 + Ruby ruby-2.0.0 + Ruby maglev + Ruby macruby-0.12 + Ruby rbx-2.0.0rc1 + Ruby ruby-1.9.3 + C ext ruby-2.0.0 + C ext jruby + Ruby jruby + Java ext 3.96s 2.48s red/black tree, pure Ruby versus native Runtime per iteration Tuesday, September 17, 13
  44. 44. 0 1 2 3 4 ruby-1.9.3 + Ruby ruby-2.0.0 + Ruby maglev + Ruby macruby-0.12 + Ruby rbx-2.0.0rc1 + Ruby ruby-1.9.3 + C ext ruby-2.0.0 + C ext jruby + Ruby jruby + Java ext 3.96s 2.48s 1.39s 1.19s red/black tree, pure Ruby versus native Runtime per iteration Tuesday, September 17, 13
  45. 45. 0 1 2 3 4 ruby-1.9.3 + Ruby ruby-2.0.0 + Ruby maglev + Ruby macruby-0.12 + Ruby rbx-2.0.0rc1 + Ruby ruby-1.9.3 + C ext ruby-2.0.0 + C ext jruby + Ruby jruby + Java ext 3.96s 2.48s 1.39s 1.19s 0.51s 0.51s 0.51s red/black tree, pure Ruby versus native Runtime per iteration Tuesday, September 17, 13
  46. 46. 0 1 2 3 4 ruby-1.9.3 + Ruby ruby-2.0.0 + Ruby maglev + Ruby macruby-0.12 + Ruby rbx-2.0.0rc1 + Ruby ruby-1.9.3 + C ext ruby-2.0.0 + C ext jruby + Ruby jruby + Java ext 3.96s 2.48s 1.39s 1.19s 0.51s 0.51s 0.51s 0.29s 0.1s red/black tree, pure Ruby versus native Runtime per iteration Tuesday, September 17, 13
  47. 47. But... • Indy was really slow in first Java 7 release • Got fast in 7u2...and turned out broken • Rewritten for 7u40 • Slow to warm up • Getting reports that there's still issues • Java 8 due in March Tuesday, September 17, 13
  48. 48. Other Options • New IR compiler/runtime in 9k • Optimize Ruby code before JVM • Specialize types, elide allocations Tuesday, September 17, 13
  49. 49. Lexical Analysis Parsing Semantic Analysis Optimization Bytecode Generation Interpret AST IR Instructions CFG DFG ... Existing New! Dalvik Generation ... Tuesday, September 17, 13
  50. 50. 1 check_arity(2, 0, -1) 2 a(0:0) = recv_pre_reqd_arg(0) 3 thread_poll 4 line_num(2) 5 %v_2 = call(+, a(0:0), [1:Fixnum]) 6 return(%v_2) -Xir.passes=LocalOptimizationPass,DeadCodeElimination def foo(a, b) c = 1 d = a + c end 0 check_arity(2, 0, -1) 1 a(0:0) = recv_pre_reqd_arg(0) 2 b(0:1) = recv_pre_reqd_arg(1) 3 %block(0:2) = recv_closure 4 thread_poll 5 line_num(1) 6 c(0:3) = 1:fixnum 7 line_num(2) 8 %v_0 = call(+, a(0:0), [c(0:3)]) 9 d(0:4) = copy(%v_0) 10 return(%v_0) Optimization propagation Tuesday, September 17, 13
  51. 51. Other Options • Truffle/Graal • New compiler backends from Oracle • Graal = direct API to native JIT • Truffle = magic optimizing AST atop Graal • Ruby on Truffle 5x-6x faster than JRuby • But... Tuesday, September 17, 13
  52. 52. The Hard Part { Tuesday, September 17, 13
  53. 53. Sooo.... • Keep working with JVM guys on InDy • Get our own optimizing compiler done • Explore Graal/Truffle backend • Compiler geeks wanted! :-) Tuesday, September 17, 13
  54. 54. Concurrency Tuesday, September 17, 13
  55. 55. True Parallellism Ruby Threads Native Threads Ruby 1.8.7 Ruby 2.0.0 Green Threading CPU Cores in Use JRuby Global LockSingle Thread Real Threading Tuesday, September 17, 13
  56. 56. Multicore in MRI 200MB MRI Instance 200MB MRI Instance 200MB MRI Instance 200MB MRI Instance 200MB MRI Instance 200MB MRI Instance 200MB MRI Instance 200MB MRI Instance 200MB MRI Instance 200MB MRI Instance 200MB MRI Instance Ten-way concurrency * 200MB = 2GB Tuesday, September 17, 13
  57. 57. Multicore in MRI 200MB MRI Instance 200MB MRI Instance 200MB MRI Instance 200MB MRI Instance 200MB MRI Instance 200MB MRI Instance 200MB MRI Instance 200MB MRI Instance 200MB MRI Instance 200MB MRI Instance 200MB MRI Instance 100-way concurrency * 200MB = 20GB 200MB MRI Instance 200MB MRI Instance 200MB MRI Instance 200MB MRI Instance 200MB MRI Instance 200MB MRI Instance 200MB MRI Instance 200MB MRI Instance 200MB MRI Instance 200MB MRI Instance 200MB MRI Instance 200MB MRI Instance 200MB MRI Instance 200MB MRI Instance 200MB MRI Instance 200MB MRI Instance 200MB MRI Instance 200MB MRI Instance 200MB MRI Instance 200MB MRI Instance 200MB MRI Instance 200MB MRI Instance 200MB MRI Instance 200MB MRI Instance 200MB MRI Instance 200MB MRI Instance 200MB MRI Instance 200MB MRI Instance 200MB MRI Instance 200MB MRI Instance 200MB MRI Instance 200MB MRI Instance 200MB MRI Instance 200MB MRI Instance 200MB MRI Instance 200MB MRI Instance 200MB MRI Instance 200MB MRI Instance 200MB MRI Instance 200MB MRI Instance 200MB MRI Instance 200MB MRI Instance 200MB MRI Instance 200MB MRI Instance 200MB MRI Instance 200MB MRI Instance 200MB MRI Instance 200MB MRI Instance 200MB MRI Instance 200MB MRI Instance 200MB MRI Instance 200MB MRI Instance 200MB MRI Instance 200MB MRI Instance 200MB MRI Instance 200MB MRI Instance 200MB MRI Instance 200MB MRI Instance 200MB MRI Instance 200MB MRI Instance 200MB MRI Instance 200MB MRI Instance 200MB MRI Instance 200MB MRI Instance 200MB MRI Instance 200MB MRI Instance 200MB MRI Instance 200MB MRI Instance 200MB MRI Instance 200MB MRI Instance 200MB MRI Instance 200MB MRI Instance 200MB MRI Instance 200MB MRI Instance 200MB MRI Instance 200MB MRI Instance 200MB MRI Instance Tuesday, September 17, 13
  58. 58. Multicore in JRuby 300MB JRuby Instance One instance across 10 threads = 300MB Tuesday, September 17, 13
  59. 59. Multicore in JRuby 300MB JRuby Instance One instance across 100 threads = 300MB Tuesday, September 17, 13
  60. 60. But... • Ruby world is still growing up • Concurrency tools being created • Libraries being made threadsafe • We need to do more to help Tuesday, September 17, 13
  61. 61. Unsafe Operations • Concurrent read+write on core structures • Non-atomic updates •@count +=1 •@cache ||= MyCache.new • Thread pooling • Coordinating threads Tuesday, September 17, 13
  62. 62. thread_safe • Concurrency-safe Hash • Concurrency-safe Array require 'thread_safe' sa = ThreadSafe::Array.new sh = ThreadSafe::Hash.new Tuesday, September 17, 13
  63. 63. hamster • Persistent collections for Ruby • A la Clojure and others simon = Hamster.hash(:name => "Simon", :gender => :male)   simon[:name] # => "Simon" simon.get(:gender) # => :male   james = simon.put(:name, "James") # => {:name => "James", :gender => :male} simon # => {:name => "Simon", :gender => :male} james[:name] # => "James" simon[:name] # => "Simon"   male = simon.delete(:name) # => {:gender => :male} simon # => {:name => "Simon", :gender => :male} male.has_key?(:name) # => false simon.has_key?(:name) # => true Tuesday, September 17, 13
  64. 64. atomic • Atomic value holder • Safely update current value • Edit value only if unchanged • Full CPU-level atomicity guarantees Tuesday, September 17, 13
  65. 65. require 'atomic' my_atomic = Atomic.new(0) my_atomic.value # => 0 my_atomic.value = 1 my_atomic.swap(2) # => 1 my_atomic.compare_and_swap(2, 3) # => true, updated to 3 my_atomic.compare_and_swap(2, 3) # => false, current is not 2 my_atomic = Atomic.new(0) my_atomic.update {|v| v + 1} begin my_atomic.try_update {|v| v + 1} rescue Atomic::ConcurrentUpdateError => cue # deal with it (retry, propagate, etc) end Tuesday, September 17, 13
  66. 66. jo • Threaded implementation of "goroutines" • "channel" for communication Tuesday, September 17, 13
  67. 67. # pinger ponger printer def pinger(c) 20.times { c << 'ping' } end def ponger(c) 20.times { c << 'pong' } end def printer(c) 40.times do puts c.take sleep 1 end end c = chan jo {pinger(c)} # all on separate threads jo {ponger(c)} jo {printer(c)} Tuesday, September 17, 13
  68. 68. Bottom Line • Concurrency can work in Ruby • Use the right tools and patterns • Immutability FTW • Test your apps and libs on JRuby! Tuesday, September 17, 13
  69. 69. Native Extensions Tuesday, September 17, 13
  70. 70. Why Not Ruby? • Performance • Fine grained (lots of calls down to C) • Coarse grained (toss work over the wall) • Library access Tuesday, September 17, 13
  71. 71. JRuby 1.6 C Exts • Limited support (now disabled) • Will be moved to external gem • If you want it, support it • Some stuff worked...most didn’t Tuesday, September 17, 13
  72. 72. Problems • Performance • Data copying to emulate raw structs • Locking to keep C code thread-safe • Multiple JRuby instances in one JVM • No way from C to know which one • Huge API to support Tuesday, September 17, 13
  73. 73. Alternatives Tuesday, September 17, 13
  74. 74. Java Integration • Call Java (Scala, Clojure, ...) from Ruby • Smart mapping of method names • Type conversions as appropriate • Super easy and fun Tuesday, September 17, 13
  75. 75. import javax.swing.JFrame import javax.swing.JLable frame = JFrame.new("Window") label = JLabel.new("Hello") frame.add(label) frame.default_close_operation = JFrame::EXIT_ON_CLOSE frame.pack frame.visible = true Tuesday, September 17, 13
  76. 76. Java Native Extensions • Similar to C ext for MRI, but with Java • Fast call protocol...basically free • Same GC for all objects • Have to keep in sync if C version too Tuesday, September 17, 13
  77. 77. FFI • Ruby API/DSL for calling native code • Runs on all Ruby impls • Maintained by JRuby team! • Solves "access" use case • Works well for coarse-grained calls Tuesday, September 17, 13
  78. 78. Ruby FFI example class Timeval < FFI::Struct   layout :tv_sec => :ulong, :tv_usec => :ulong end module LibC   extend FFI::Library   ffi_lib FFI::Library::LIBC   attach_function :gettimeofday, [ :pointer, :pointer ], :int end t = Timeval.new LibC.gettimeofday(t.pointer, nil) Tuesday, September 17, 13
  79. 79. But... • Struct binding issues • Across OSes (also 32+64 bit archs) • Across library versions • Library compile option mismatches • Fine-grained perf sometimes suffers Tuesday, September 17, 13
  80. 80. Ruby FFI Generator • https://github.com/neelance/ffi-gen • Clang-based Ruby FFI generator • Used to generate clang binding it uses • It's meta! Tuesday, September 17, 13
  81. 81. require "ffi/gen" FFI::Gen.generate( module_name: "Clang", ffi_lib: "clang", headers: ["clang-c/Index.h"], cflags: `llvm-config --cflags`.split(" "), prefixes: ["clang_", "CX"], output: "clang-c/index.rb" ) Tuesday, September 17, 13
  82. 82.   # A single translation unit, which resides in an index.   class TranslationUnitImpl < FFI::Struct     layout :dummy, :char   end   # Identifies a specific source location within a translation   # unit.   #   # Use clang_getExpansionLocation() or clang_getSpellingLocation()   # to map a source location to a particular file, line, and column.   #   # = Fields:   # :ptr_data ::   # (Array<FFI::Pointer(*Void)>)   # :int_data ::   # (Integer)   class SourceLocation < FFI::Struct     layout :ptr_data, [:pointer, 2],            :int_data, :uint   end Tuesday, September 17, 13
  83. 83.   # Retrieves the source location associated with a given file/line/column   # in a particular translation unit.   #   # @method get_location(tu, file, line, column)   # @param [TranslationUnitImpl] tu   # @param [FFI::Pointer(File)] file   # @param [Integer] line   # @param [Integer] column   # @return [SourceLocation]   # @scope class   attach_function :get_location, :clang_getLocation, [TranslationUnitImpl, :pointer, :uint, :uint], SourceLocation.by_value Tuesday, September 17, 13
  84. 84. XNI • Ruby + plain old C • Covers access and perf cases • Cross-implementation support • Struct mapping in compile phase • Experimental https://github.com/wmeissner/xni Tuesday, September 17, 13
  85. 85. hitimes C Ext /** * call-seq: * interval.start -> boolean * * mark the start of the interval. Calling start on an already started * interval has no effect. An interval can only be started once. If the * interval is truely started +true+ is returned otherwise +false+. */ VALUE hitimes_interval_start( VALUE self ) {     hitimes_interval_t *i;     VALUE rc = Qfalse;     Data_Get_Struct( self, hitimes_interval_t, i );     if ( 0L == i->start_instant ) {       i->start_instant = hitimes_get_current_instant( );       i->stop_instant = 0L;       i->duration = -1.0l;       rc = Qtrue;     }     return rc; } Tuesday, September 17, 13
  86. 86. hitimes XNI /** * call-seq: * interval.start -> boolean * * mark the start of the interval. Calling start on an already started * interval has no effect. An interval can only be started once. If the * interval is truely started +true+ is returned otherwise +false+. */ bool hitimes_interval_start( RubyEnv* env, hitimes_interval_t* i ) {     if ( 0L == i->start_instant ) {       i->start_instant = hitimes_get_current_instant( );       i->stop_instant = 0L;       i->duration = -1.0l;       return true;     }     return false; } Tuesday, September 17, 13
  87. 87. Startup Time Tuesday, September 17, 13
  88. 88. #1 Pain Point Tuesday, September 17, 13
  89. 89. Hard Problem • MRI boot time is 95% native • JRuby boot time is 0% native code • Mostly Java, which needs to warm up • Parser, interpreter, core classes, compiler • Even if our code is better, we start slow Tuesday, September 17, 13
  90. 90. Child Processes • Reduce need for sub-Ruby invokes • rails -> clean rails env in child • rails/rake -> bundler relaunch • rake test -> 4+ processes in Rails • rake -> rspec in subprocess • Fix requires changing many libraries Tuesday, September 17, 13
  91. 91. Lexical Analysis Parsing Semantic Analysis Optimization Bytecode Generation Interpret AST IR Instructions CFG DFG ... Existing MORE Dalvik Generation ... Tuesday, September 17, 13
  92. 92. Solutions Tuesday, September 17, 13
  93. 93. Nailgun/Drip • Always running background JVM • Not quite production quality • signals, IO • Small Ruby scripts very fast • Rails not much faster • Lots of requires, objects, boot logic Tuesday, September 17, 13
  94. 94. GSoC 2012 IR Persistence IR Instructions CFG DFG ... file.ir file.rb compile file.c compile file.o Tuesday, September 17, 13
  95. 95. Reflection on GSoC • Size matters • # of bytes • Intern()‘ing of identifiers matter • Laziness can help a lot Tuesday, September 17, 13
  96. 96. Defined vs Used Methods CMD DEFINED USED SAVINGS -e ‘:foo’ 501 33 ~93% gem install rails 1897 529 ~72% rails scaffold 9411 1647 ~82% rake db:migrate 9397 1662 ~82% rake spec 4595 904 ~80% Tuesday, September 17, 13
  97. 97. New IR Persistence • Binary format • Constant pool to intern only once per id • (currently once per occurrence) • Incremental loading of method bodies Tuesday, September 17, 13
  98. 98. Ultimate Startup! rails new foo JRuby Instance IR Data rails generate JRuby Instance rake db:migrate JRuby Instance Compile Use Use Background JVM Tuesday, September 17, 13
  99. 99. Ruby is Strong • Still growing and improving • MRI too! • Concurrency can be done • C extensions are holding us back • Never surrender! Tuesday, September 17, 13
  100. 100. ThankYou! • Charles Oliver Nutter • @headius • headius@headius.com • http://blog.headius.com Tuesday, September 17, 13

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