A Whole New World: Rails on the JVM with JRuby!

Transcript

1. A Whole New World!
   Rails on the JVM with JRuby!
   

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2. Who Am I
   • Charles Oliver Nutter
   
   
   • @headius(@mastodon.social)
   
   
   • [email protected]
   
   
   • JRuby developer since 2004
   
   
   • Full-time JRuby and JVM language
   advocate since 2006
   

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5. What is JRuby?
   • An implementation of Ruby atop the Java Virtual Machine
   
   
   • Ruby implementation
   fi
   rst, JVM language second
   
   
   • Many bene
   fi
   ts from JVM ecosystem
   
   
   • Ruby code should "just work"
   
   
   • Different extension API, no forking, parallel threads
   
   
   • www.jruby.org
   

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7. Ruby Compatibility
   • JRuby 9.4 is out now!
   
   
   • Ruby 3.1 compatible, 98% of language specs passing
   
   
   • Nearly complete core + stdlib features from 2.7, 3.0 and 3.1
   
   
   • JRuby 9.3 (Ruby 2.6 compat)
   
   
   • Maintenance through 2023 as needed
   
   
   • Compatibility before performance!
   
   
   • Now we can refocus on optimization again
   

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8. Ruby 3.2 Coming Soon!
   • Checklist issue: jruby/jruby#7517
   
   
   • You can help us add missing features!
   
   
   • Hopefully release 3.2 compatibility in the next 6 months
   

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9. Why JRuby?
   • JVM GC, JIT, concurrency scales Rails extremely well
   
   
   • Rich tools for monitoring, pro
   fi
   ling, debugging
   
   
   • Wide platform support: desktop, server, mobile
   
   
   • Zero-compile cross-platform GUI support
   
   
   • Java ecosystem moving fast, with thousands of excellent libraries
   

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10. Getting Started
    

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12. JRuby Install
    • Install a JDK
    
    
    • Java 11+ recommended, there's many distributions out there
    
    
    • Java 8 supported for 9.4 and lower
    
    
    • Install JRuby
    
    
    • Recommended: system package, Ruby installer, Docker image
    
    
    • Download tarball/zip or Windows installer
    

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13. Test it out!
    [] ~ $ rvm use jruby
    
    
    Using /Users/headius/.rvm/gems/jruby-9.4.2.0
    
    
    [] ~ $ irb
    
    
    >> runtime = java.lang.Runtime.runtime
    
    
    => #
    
    
    >> runtime.available_processors
    
    
    => 8
    
    
    >> runtime.free_memory
    
    
    => 91420584
    
    
    >>
    

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14. JRuby on Rails
    

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15. JRuby Runs Rails!
    • Since 2007!
    
    
    • "Are there JRuby users running Rails applications?"
    
    
    • Oh yes! And at large scale!
    
    
    • Bene
    fi
    t from the JVM, libraries, languages
    
    
    • Great way to scale large Rails apps today!
    

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16. Rails 7
    • Rails 7 works on JRuby 9.4!
    
    
    • activerecord-jdbc for JRuby: SQLite, MySQL, PostgreSQL
    
    
    • Version 60.0 for Rails 6, 70.0 for Rails 7, etc
    
    
    • Oracle, SQL Server, DB2, are available, may need updates
    
    
    • Performance and compatibility looking good!
    

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17. Rails 7
    actioncable: 203 runs, 921 assertions, 0 failures, 10 errors
    actionmailbox: 92 runs, 238 assertions, 0 failures, 0 errors
    actionmailer: 230 runs, 516 assertions, 0 failures, 1 errors
    actionpack: 3550 runs, 16802 assertions, 1 failures, 1 errors
    actiontext: 80 runs, 145 assertions, 7 failures, 2 errors
    actionview: 2424 runs, 5395 assertions, 2 failures, 4 errors
    activejob: 368 runs, 837 assertions, 0 failures, 0 errors
    activemodel: 966 runs, 2853 assertions, 5 failures, 0 errors
    activestorage: 392 runs, 1121 assertions, 0 failures, 0 errors
    activesupport: 5188 runs, 12926 assertions, 43 failures, 28 errors
    99% passing!
    

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18. Minimal Con
    fi
    g Changes
    • Generate a new app, Rails will use JRuby defaults
    
    
    • Use threads in Puma instead of workers
    
    
    • 2n+1 is a good rule of thumb
    
    
    • Make sure to increase DB connections as well
    
    
    • Existing app: try bundling, replace unsupported libs
    
    
    • Let us know! We can prioritize adding JRuby support!
    

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20. Scaling Rails with JRuby
    

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21. Scaling Rails
    • Classic problem on CRuby/MRI
    
    
    • No concurrent threads, so we need worker processes
    
    
    • Processes duplicate runtime state and waste resources
    
    
    • JRuby is the answer!
    
    
    • Multi-threaded single process runs your entire site
    • Single process with leading-edge GC uses resources better
    

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22. Baseline Rails App
    • Scaffolded "blog" application on
    PostgreSQL, Puma
    
    
    • IBM VPC instance: 8 vCPU, 32GB
    
    
    • CRuby 3.2, 16 workers
    
    
    • JRuby 9.4: 16 threads
    
    
    • Database, siege benchmark driver
    on same instance
    

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23. Workers vs Threads
    • Workers duplicate a lot of work
    
    
    • N * GC overhead, single large heap is better
    
    
    • N * JIT overhead and memory usage
    
    
    • Unavoidable to have some duplicated memory
    
    
    • JVM and JRuby support real parallel threads
    
    
    • One process, one GC, one JIT scales all the way up
    

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24. Caveats
    • PostgreSQL local via Docker (<5% overhead)
    
    
    • Siege benchmark driver also local (<5% overhead)
    
    
    • Very minimal blog app, full end-to-end requests
    
    
    • JRuby tuning and warmup time are important
    

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25. Requests per second
    0
    450
    900
    1350
    1800
    60s siege iteration
    1 2 3 4 5 6 7
    JRuby 9.4 CRuby 3.2
    

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26. requests per second (higher is better)
    0rps
    450rps
    900rps
    1350rps
    1800rps
    1,280rps
    1,705rps
    JRuby 9.4 CRuby 3.2
    

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27. Memory
    • Baseline
    
    
    • JRuby: 3.4GB RSS
    
    
    • CRuby: 16x 103MB = 1.6GB
    
    
    • With tuning options
    
    
    • JRuby with 300MB heap: 955MB
    
    
    • CRuby YJIT: 16x 125MB = 2GB
    

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28. Requests per second
    0
    450
    900
    1350
    1800
    60s siege iteration
    1 2 3 4 5 6 7
    JRuby CRuby 3.2 JRuby 300MB heap CRuby 3.2 + YJIT
    

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29. requests per second (higher is better)
    0rps
    450rps
    900rps
    1350rps
    1800rps
    1,550rps
    1,643rps
    1,280rps
    1,705rps
    JRuby 9.4 CRuby 3.2 JRuby 300MB heap CRuby + YJIT
    

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30. JRuby on Rails Scales!
    • More requests per second with lower latency
    
    
    • Lower memory usage beyond 8-10 concurrent users
    
    
    • Deploy anywhere that has a JVM (which is basically everywhere)
    
    
    • Leverage JVM tools to monitor and optimize
    

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31. True Story
    • Large Rails application using 40 xlarge on EC2
    
    
    • 40 worker processes per server
    
    
    • 100k-150k req/min, 50-75ms response times
    
    
    • Migrated app to JRuby, made more use of threading
    
    
    • Down to 10 xlarge, 75% cost reduction
    
    
    • Consistently over 150k req/min, 30ms response times
    $
    

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32. Deploying JRuby the Ruby Way
    • Typical servers, devops tools in Ruby work
    fi
    ne
    
    
    • Usually no compilation required; install and go
    
    
    • Scales great with Puma
    
    
    • Rails using Puma by default
    
    
    • Small frameworks (e.g. Sinatra, Roda) scale even better
    

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33. Deploying with Warbler
    • gem install warbler ; warble
    
    
    • Bundle your app + libs + JRuby into a single
    fi
    le
    
    
    • Hand off to ops to deploy or run as executable (w/ built-in server)
    
    
    • One click deploy to Java clouds:
    
    
    • Elastic Beanstalk, Google AppEngine, etc
    
    
    • github.com/jruby/warbler
    

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34. But wait, there's more!
    

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35. So much more!
    • JVM and JRuby have much more to offer
    
    
    • We'll cover a few areas that make JRuby stand out
    
    
    • Some of these are early or experimental, but very exciting!
    

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36. JVM Tools
    

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37. JDK Flight Recorder
    • Low-overhead monitoring and pro
    fi
    ling for JVM
    
    
    • Always-on monitoring <1% overhead
    
    
    • Active pro
    fi
    ling around 5% overhead
    
    
    • Track memory, heap usage, GC, hot methods, JIT activity
    
    
    • Think New Relic, AppSignal, Sentry.io... but built-in and FREE
    

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38. JDK Mission Control
    • GUI control center and visualizer for Flight Recorder data
    
    
    • Start and manage recordings
    
    
    • Save, load, and browse recorded data
    
    
    • https://adoptium.net/jmc/
    

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45. Visual VM
    

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46. GUI and Graphics
    

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47. GUI Libraries
    • Swing, built into JDK
    
    
    • Clean, cross-platform, easy to build simple UIs
    
    
    • Scalable Windowing Toolkit (Eclipse SWT)
    
    
    • Native widgets, WebKit browser component, rich ecosystem
    
    
    • JavaFX (via JRubyFX, github/jruby/jrubyfx)
    
    
    • Scene-based, vector drawing, event-driven modern UI library
    

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48. Shoes 4
    

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49. Glimmer
    • Glimmer GUI DSL
    
    
    • Multiple backends (SWT, GTK, ...)
    
    
    • JRuby + SWT is the most mature
    
    
    • JRuby makes cross-platform GUI
    much easier!
    
    
    • Works same everywhere
    
    
    • GUI libraries shipped with gem
    

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50. Purugin for Minecraft
    event(:player_egg_throw) do |e|
    e.hatching = true
    e.num_hatches = 120
    e.player.mesg "hatched"
    end
    

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51. GUIs... like Android?
    

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52. Ruboto: JRuby on Android
    • ruboto.org
    
    
    • Actively used for commercial
    projects today
    
    
    • Build interface with GUI builder, wire
    it up with Ruby code
    
    
    • Neglected a bit but being updated
    for JRuby 9.4 now!
    

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54. Trying Ruboto IRB
    • Original was pulled from store because it asked for ALL privileges!
    
    
    • Duh, it was a tech demo and REPL
    
    
    • We will republish soon, but search for two packages to download:
    
    
    • Ruboto Core: JRuby and Ruboto framework as a shared package
    
    
    • Ruboto IRB: REPL, editor, example scripts
    

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55. More JVM Features for Ruby
    

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56. InvokeDynamic
    

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57. InvokeDynamic
    • User-de
    fi
    ned binding of methods and values
    
    
    • Language decides target based on dynamic lookup logic
    
    
    • JVM optimizes that target like static code
    
    
    • Introduced in Java 1.7 (2011) with input from JRuby
    
    
    • Key to JRuby performance!
    

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58. InvokeDynamic Performance
    Times faster than JRuby Java 8 no indy
    0
    1.25
    2.5
    3.75
    5
    Mandelbrot Red/Black
    4.05x
    3.92x 3.74x
    3.68x 3.72x
    1.97x
    Java 8 indy Java 11 indy Java 17 indy
    3.28x CRuby JIT 1.86x CRuby JIT
    

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59. Indy + Graal JIT?
    Times faster than JRuby Java 8 no indy
    0
    4
    8
    12
    16
    Mandelbrot Red/Black
    3.13x
    15.7x
    4.05x
    3.92x 3.74x
    3.68x 3.72x
    1.97x
    Java 8 indy Java 11 indy Java 17 indy Graal CE indy
    Escape analysis
    But not always better
    

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60. Project Loom
    

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61. Project Loom
    • JRuby's
    fi
    bers are based on threads
    
    
    • Too many, JVM blows up!
    
    
    • Scheduling, resource-intensive
    
    
    • Loom brings
    fi
    bers to JVM
    
    
    • Easily handles thousands of
    fi
    bers
    
    
    • Faster context-switching
    

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64. 5.times do
    t = Time.now
    # create 100k fibers
    ary = 100_000.times.map { Fiber.new { } }
    # resume and complete 100k fibers
    ary.each(&:resume)
    p Time.now - t
    end
    

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65. $ jruby fiber_test.rb
    [7.603s][warning][os,thread] Attempt to protect stack guard pages failed
    (0x00007fc240a00000-0x00007fc240a04000).
    #
    # A fatal error has been detected by the Java Runtime Environment:
    # Native memory allocation (mprotect) failed to protect 16384 bytes for
    # memory to guard stack pages
    #
    # An error report file with more information is saved as:
    # /home/headius/work/jruby93/hs_err_pid75149.log
    #
    # If you would like to submit a bug report, please visit:
    # https://bugreport.java.com/bugreport/crash.jsp
    #
    Aborted (core dumped)
    😩
    

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66. --enable-preview
    

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67. $ jruby -J--enable-preview fiber_test.rb
    2.324123
    0.880373
    0.6916289999999999
    0.73703
    0.655856
    🤩
    

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68. Project Panama
    • Foreign function interface (FFI)
    
    
    • With JVM help to make direct calls
    
    
    • Foreign memory API
    
    
    • JVM-assisted access, lifecycle
    
    
    • API extraction from C/++ headers
    
    
    • Save time setting up bindings
    

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69. jextract code generator
    • Writing bindings using FFI or Fiddle is still challenging
    
    
    • Parameter sizes, struct layout, in and out values, pointers
    
    
    • Differences across platforms
    
    
    • jextract: produce Panama/FFI stub code from a C header
    fi
    le
    
    
    • Call that stub code from JRuby... easy FFI for all!
    

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70. Wrapping Up
    

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71. JRuby Future
    • JRuby 9.4 continues to stablize
    
    
    • Many production users already!
    
    
    • Big optimization work coming the rest of this year
    
    
    • JRuby 9.5: Java 17 minimum, Ruby 3.2 support, many optimizations
    
    
    • Lots of new JVM features to leverage
    
    
    • Looking into native compilation, snapshotting for fast startup!
    

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72. JRuby on Rails Future
    • Rails 7 support is looking great!
    
    
    • We are caught up again, will keep tracking updates
    
    
    • As your app grows, JRuby can help you scale
    
    
    • Reduce resources, save money 🤑
    
    
    • Let's talk about running your app on JRuby!
    

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73. Thank You!
    • Charles Oliver Nutter
    
    
    • [email protected]
    
    
    • @headius
    
    
    • https://github.com/jruby/jruby
    
    
    • https://www.jruby.org
    

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