Concurrency & Parallel Programming
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The document discusses concurrency and parallel programming, highlighting the differences and applications of both concepts. It covers various topics such as multi-core CPUs, functional programming, and the history of programming languages like Haskell and Elixir, along with their respective use cases. Additionally, it touches on challenges related to threads, race conditions, and deadlocks while mentioning tools and features for effective programming.
Concurrency & Parallel Programming
- 1. Concurrency & Parallel Programming by Ramazan AYYILDIZ rayyildiz.me@rayyildiz
- 3. Moore’s Law ansistors incorporated in a chip will approximately double e
- 6. Parallel Programming • Uses a multiplicity of computational hardware (e.g., several processor cores) to perform a computation more quickly
- 7. Concurrency • A programming structuring technique in which there are multiple threads of control.
- 11. Parallel Architecture • Instruction Level Parallelism • 8 bit —> 16 bit —> 32 bit —> 64 bit —> … • Data parallelism • GPU • Intel accured Altera ~17 Billion USD
- 13. Threads
- 14. Threads • Simple thread for java • java.util.Thread • Mutex, Deadlock, Race Condition, Lock
- 15. Simple Thread
- 16. • Why Thread.yield() • a hint to schedule that the current thread is willing to yield its current use of processor • Why Thread.join()
- 18. Race Condition
- 19. Solution of Race Condition • synronized keyword • java.util.Lock • Immutable • Atomic Integer
- 20. Multiple Locks?
- 21. Dining Philosophers • A philosopher is either hungry or thinking • If he is hungry, he picks up a chopsticks on either side of him and eats for a while. • When he is done, he puts them down
- 22. DEADLOCKS
- 23. • java 6 has java.util.concurrent package. • This package has great features • Use case : • XBRL instance creation ( 5-6 financial table in parallel by Executer Tasks) • Load tests 75 —> 150 concurrent user
- 24. If it Hurts,Stop doing it
- 26. Functional Programming • Imperative program has series of statements that changes global state when executed • A functional programming ( aka FP) computation as evaluation of expression. • Those expressions are built from pure mathematical functions • Side effect free
- 27. • FP is useful for concurrency because lack of side effect makes reasoning about thread safety much easier. • FP allows parallelism to be represented directly. • If data is immutable ( not shared mutable state) can be accessed by multiple threads without any kind of locking.
- 28. History of FP • FP invented in 1930s, Lambda Calculus • in 1950s, LISP was created by John McCarthy • in 1970s, ML was created Robin Milner and David Turner. • in 1987, Haskell began with a consensus (open standards)
- 29. Haskell Basic Features • Pure Function • First Class and higher order function • Recursion • Immutable • Lazy evaluation
- 31. Fibonacci Number in Haskell
- 32. Use Case : Facebook Spam detection ( HAXL)
- 33. Actor Model
- 35. Elixir • Created by Jose Valim in 2012 • Syntax is similar to Ruby • Runs on Erlang Virtual Machine (BEAM) • Functional • Erlang process (actor)
- 37. Use Case : Pinterest • 14000 notification per seconds • Runs on 15 server( old one runs on 30 server) • Pinterest API : response time is about 500 µs https://engineering.pinterest.com/blog/introducing-new-open-source-tools-elixir-community
- 38. Use Case : Whatsapp • Run on Erlang BEAM/OTP • 1+ Million user signup per day • 50 Million messages per day • 14 Million active users per day • Total 450 Million users • >8000 cores • > 70Million Erlang messages per day • 2 Million connection per server http://highscalability.com/blog/2014/2/26/the-whatsapp-architecture-facebook-bought-for-19-billion.html
- 39. Questions ?
- 40. Bonus Sections
- 41. Bonus - 1 • Clojure • Created by Rich Hickey in 2007 • Inspired by LISP • Runs on JVM • Clojure Agent: shared access to mutable state. • No blocking receive
- 42. Bonus - 2 • Is FP (Haskell) ready for industry ? • Linq invented by Eric Meijer • Scala, F# , Swift, even Java 8 has FP features
- 43. Bonus - 3 • I love imperative style, which programming language may I use ? • GOLANG : • is invented after multi core • Has Garbage Collector • Has go-routine & chain