Parallel Computing

with ruby

My Company

My Company

Challenges

• Learning Ruby

Challenges

• Learning Ruby

• Rails 2 to Rails 3

Challenges

• Learning Ruby

• Rails 2 to Rails 3

• Integrating with Banking APIs

Challenges

What is Parallel Computing?

Multithreading!vs!

Multiprocessing

Share Memory Space!

Lightweight!

May Have Memory Management Issues!

Can Sometimes Take Advantage of Multiple CPUs

Thread ProcessSeparate Memory Space!

Requires More Memory!

No Multithreading Issues!

Can Take Advantage of Multiple CPUs

CPU Scheduling

High IO

High CPU

http://www.cs.rutgers.edu/~pxk/416/notes/07-scheduling.html

High I/O

High IO

Fill these I/O blocks with other CPU tasks!

Multithreading ticker

t1 = Thread.new do puts "[Thread 1] Started" sleep 2 puts "[Thread 1] Completed"end!t2 = Thread.new do 5.times do |n| puts "[Thread 2] tick #{n}" endend

Multithreading ticker

t1 = Thread.new do puts "[Thread 1] Started" sleep 2 puts "[Thread 1] Completed"end!t2 = Thread.new do 5.times do |n| puts "[Thread 2] tick #{n}" endend

$ ruby thread_ticker.rb [Thread 1] Started [Thread 2] tick 0 [Thread 2] tick 1 [Thread 2] tick 2 [Thread 2] tick 3 [Thread 2] tick 4

Multithreading ticker

t1 = Thread.new do puts "[Thread 1] Started" sleep 2 puts "[Thread 1] Completed"end!t2 = Thread.new do 5.times do |n| puts "[Thread 2] tick #{n}" endend

Where’s Completed ?

$ ruby thread_ticker.rb [Thread 1] Started [Thread 2] tick 0 [Thread 2] tick 1 [Thread 2] tick 2 [Thread 2] tick 3 [Thread 2] tick 4

Multithreading tickert1 = Thread.new do puts "[Thread 1] Started" sleep 2 puts "[Thread 1] Completed"end!t2 = Thread.new do 5.times do |n| puts "[Thread 2] tick #{n}" endend!t1.joint2.join

Multithreading tickert1 = Thread.new do puts "[Thread 1] Started" sleep 2 puts "[Thread 1] Completed"end!t2 = Thread.new do 5.times do |n| puts "[Thread 2] tick #{n}" endend!t1.joint2.join

$ ruby thread_ticker.rb [Thread 1] Started [Thread 2] tick 0 [Thread 2] tick 1 [Thread 2] tick 2 [Thread 2] tick 3 [Thread 2] tick 4 [Thread 1] Completed

Issues with Threads

No control when Threads are preempted!

Deadlock!

Race conditions!

Hard to debug

Race Condition

Race Condition

Race Condition

Fibers

Fibers

Programmers specify when to give up control!

Prevents concurrency issues!

Lightweight

Fibers vs Threads

http://oldmoe.blogspot.com/2008/08/ruby-fibers-vs-ruby-threads.html

Fibonacci

fib = Fiber.new do f1 = f2 = 1 loop do Fiber.yield f1 f1, f2 = f2, f1 + f2 endend!5.times { p fib.resume }

$ ruby fiber_fib.rb11235

Fiber Tickerrequire 'fiber'!fb1 = Fiber.new do puts "[Fiber 1] Started" sleep 2 puts "[Fiber 1] Completed"end!fb2 = Fiber.new do 5.times do |n| puts "[Fiber 2] tick #{n}" endend!fb1.resumefb2.resume

Fiber Tickerrequire 'fiber'!fb1 = Fiber.new do puts "[Fiber 1] Started" sleep 2 puts "[Fiber 1] Completed"end!fb2 = Fiber.new do 5.times do |n| puts "[Fiber 2] tick #{n}" endend!fb1.resumefb2.resume

$ ruby fiber_tick.rb [Fiber 1] Started [Fiber 1] Completed [Fiber 2] tick 0 [Fiber 2] tick 1 [Fiber 2] tick 2 [Fiber 2] tick 3 [Fiber 2] tick 4

http://schmurfy.github.io/2011/09/25/on_fibers_and_threads.html

Event Machine

https://github.com/eventmachine/eventmachine

Evented Tickerrequire 'fiber'require 'eventmachine'!EM::run do fb1 = Fiber.new do puts "[Fiber 1] Started" EM::add_timer(2){ fb1.resume } Fiber.yield puts "[Fiber 1] Completed" EM::stop() end! fb2 = Fiber.new do 5.times {|n| puts "[Fiber 2] tick #{n}" } end! fb1.resume fb2.resumeend

$ ruby evented_ticker.rb [Fiber 1] Started [Fiber 2] tick 0 [Fiber 2] tick 1 [Fiber 2] tick 2 [Fiber 2] tick 3 [Fiber 2] tick 4 [Fiber 1] Completed

When does Multithreading help?

High I/O time such as

File I/O DB call API request

Demo

https://github.com/sudizhe/parallel_programming_demo

Fibers

Programmers specify when to give up control!

Prevents concurrency issues!

Lightweight

Multiprocessing?

http://www.igvita.com/2008/11/13/concurrency-is-a-myth-in-ruby/

Multiprocessing?

http://www.igvita.com/2008/11/13/concurrency-is-a-myth-in-ruby/

Global Interpreter Lock (GIL)

Multiprocessing?

http://www.igvita.com/2008/11/13/concurrency-is-a-myth-in-ruby/

Global Interpreter Lock (GIL)

Rails Deploy

Spawning Processes

Parallel Gem

inDinero Enterprise

inDinero Enterprise

150,000 Transactions

inDinero Enterprise

150,000 Transactions x 15,000 Rules

RecapMultithreading

Thread Class

Fibers

Event Machine

Multiprocessing

Process Class

Unicorn Magic

Hadoop

Q & A