Concurrency

How to shoot yourself in both feet.Simultaneously.

Victor HaydinR&D Manager @ ELEKS

The Problem

Multithreading?Parallelism?

Concurrency?

Single threaded programming

Concurrent programming*

* as you imagine it

Concurrent programm

ing** in real world

Shared state

Traditional way

WTF?!

Web 2.0 – 2003First dual-core CPU – 2005Cloud Computing - 2006

C++ - 1983Java - 1995C# - 2001

Alternate ways

Transactional memoryFunctional programming

Messaging

atomic {if (from.Ballance < amount)

throw new InsufficientBalanceException("Not enough money"); from.Debit(amount); to.Credit(amount);}

Atomic.Do(() => {if (from.Ballance < amount)

throw new InsufficientBalanceException("Not enough money"); from.Debit(amount); to.Credit(amount);});

STM HTM

Immutable data means no side effects. No side effects – no

concurrency problems!*

* except if you need I/O

Wait a second, what about I/O?

FP != easy concurrencyFP == easy parallelism

NActStact

Retlang

…or use single thread.

Q&A