concurrency patterns in ruby
DESCRIPTION
Ruby is a wonderful language for rapid development, it is easy to learn, we have wonderful frameworks, an active and dynamic community. But when it comes to concurrency Ruby is plagued with problems, controversies and urban legends. A lot of people would know about green threads in Ruby, GIL and its inherent limitations. But that it only one part of the big picture. Ruby offers much more than threads to helps us with concurrency.This presentation explores other options of writing highly concurrent applications in Ruby and options available in it. We cover topics ranging from Actor like message passing concurrency in Ruby, dataflow concurrency of how we can coordinate across different threads, Event driven methods, coroutine based concurrency which never blocks ;) and finally Software Transactional Memory. We look at lots of code, some serious looking yet colorful performance graphs comparisons, and conditions at which each of these forms are concurrency are effective and ineffective.TRANSCRIPT
Paradigms of Concurrency
Why is this important?
Or for geeks to relate...
Without right abstractions...
So what do we have in hand?
● Threads – The Java hangover● Fibers – Red headed cousin of threads● Actors – Stylish but effective● Reactor – He will do all the work...● Dataflow – The forgotten one..● STM – Remember ATM● The Nirvana
A folk definition of insanity is to do the same thing over and over again and to expect the results to be different. By this definition, we in fact require that programmers of multithreaded systems be insane - The Problem with Threads Edward Lee
Threading in Ruby
Concurrency is a myth Ruby - @igvita
Fibers
● New kid in the block from Ruby 1.9● Green threads with cooperatively
scheduler● Can give up CPU control to other fiber
when needed.● Based on Coroutines – Like python
generators but can yield to other coroutines
● Think NeverBlock...
Nginx vs Apache Death Match
EventMachine – Reactor Pattern
EventMachine
● Based on python Twisted● Reactor sits in the middle● IOC pattern – Not many get used to it● Defer long running process● Support for lot of protocols and very
active development● Try my em-couchdb :)
(http://github.com/saivenkat/em-couchdb)
Actors -Stylishly passing messages
Actors
● Message passing concurrency● No first class support in Ruby● Revactor is good but we had problems
with it● If Jruby, lots of Java Actor framework
available like Jetlang.● Jruby + Jetlang - http://bit.ly/ahXh6j
Transactions – We are safe
Software Transactional Memory
● Similar to database transactions but inmemory (ACIDXX)
● Unfortunately again no first class support
● STM library by MentalGuy - http://bit.ly/c7Mxah
● In Jruby harness clojure's infrastructure – Ruby objects as refs. http://bit.ly/d6vpuP
Multi Process
Coordination
Coordination
● How do we coordinate independent units of execution?
● Dataflow – Forgotten paradigm● Other methods – May be a big heavy
weight suitable when multi processing● Tuplespace, Queues (RabbitMq or
beanstalk)
Nirvana
Nirvana
● Polyglotism – Let the languages which excel in concurrency do the job
● Make Ruby talk with Clojure, Erlang, Haskell, node.js...
● Lots of ways. VM level support, external infrastructure.
Sai Venkatgithub.com/saivenkat
@sai_venkathttp://developer-in-test.blogspot.com
HariKrishnangithub.com/harikrishnan83
@harikrishnan83http://harikrishnan83.wordpress.com
All images used are attributed to the awesome guys who took them..
Please don't sue us :D
