Fiber and em-synchrony

Introduce Fiber in Ruby and demonstrate how to run Rails application using em-synchrony to utilize asynchronous councurrency

Transcript

1. Fiber and Em-synchrony @ShiningRay
2. Fiber Fibers are primitives for implementing light weight cooperative concurrency in Ruby. Add to Ruby core in 1.9
3. Fiber == Coroutine
4. Fiber vs Thread vs Process • Process simulates CPU and Memory, Preemptive • Thread simulates CPU, Preemptive • Fiber: none, cooperative, manually schedule
5. Coroutine vs Routine • Routine: return only once • Coroutine: can return(yield) multiple times
6. Benefit of Fibers • Small & lightweight: much smaller than thread/process, so we can spawn more. • Can be schedule only when necessary, reduced context-switch, lighten the burden of CPU. • So can handle higher concurrency than per- thread or per-process mode.
7. PS: Coroutines can be implemented by call/cc.
8. Warning: Fiber can also lead to concurrent problem like race condition.
9. Em-Synchrony = Fiber + EventMachine
10. Em-Synchrony: Good Parts • High Concurrency of evented model • Ease of sequential programming, no pain of callbacks https://github.com/igrigorik/em-synchrony
11. Basic Idea • Untangling Evented Code with Ruby Fibers • http://www.igvita.com/2010/03/22/untangling-eve nted-code-with-ruby-fibers/
12. Basic Idea • Use Fiber to save the context after sending a asynchronous request. • Switch back to parent Fiber(for scheduling other fibers) • Resume the saved Fiber after asynchonous request completes.
14. More • Fiber aware ConnectionPool with sync/async query support • Fiber aware Iterator to allow concurrency control & mixing of sync / async • Fiber aware async inline support: turns any async function into sync • Fiber aware Multi-request interface for any callback enabled clients • Fiber aware TCPSocket replacement, powered by EventMachine • Fiber aware Thread, Mutex, ConditionVariable clases • Fiber aware sleep, defer, system
15. High-concurrency Framework using em-synchrony • Goliath • Sinatra-synchrony
16. Em-Synchrony: The Bad Parts • You must use a customized fiber aware driver for asynchronous tasks. (em-mysql em-redis ...)
17. Suitable for Web Service APIs
18. Asynchronous Rails
19. You need • Em-synchrony • Rack-fiber_pool • Config.threadsafe! • Thin(evented server) • Fiber aware driver for (db/http/service) connections
20. Gemfile
21. Config.ru
22. Application.rb
23. Database.yml
24. Use Ruby 2.0 Ruby 1.9 4k Fiber stack size. Too small to fit common Rails app. Ruby 2.0 has 200k default Fiber stack size. And you can change it via:
25. Thank you