High level concurrency

High%level)Concurrency
©"Robert"Brown"August"2015"@robby_brown

Overview
1. The&Problems
2. Architecture&Theory
3. Examples
4. Demo

The$Problems

Atomicity

Nondeterminism

Race%Condi+ons

Mutual&Exclusion

Dead%lock

The$list$goes$on...

Keeping'track'of'so'much'informa3on'is'hard

Computers*are*good*at*tracking*lots*of*
informa4on

We#write#code#that#tests#code.
We#write#code#that#generates#code.

Let's&use&a&system&that&lets&the&computer&
manage&concurrency

Architecture)Theory

Actor&Model

A"universal"primi.ve"of"concurrent"
computa.on.
—"Deﬁni(on"of"an"Actor1
1
"Wikipedia

[T]he&problem&with&[OOP]&languages&
is&they’ve&got&all&this&implicit&
environment&that&they&carry&around&
with&them.
—"Joe"Armstrong3
3
"Coder's"at"Work

You$wanted$a$banana$but$what$you$
got$was$a$gorilla$holding$the$banana$
and$the$en3re$jungle.
—"Joe"Armstrong3
3
"Coder's"at"Work

I'm$sorry$that$I$long$ago$coined$the
term$"objects"$for$this$topic$because$
it$gets$many$people$to$focus$on$the
lesser$idea.
—"Alan"Kay2
2
"Squeak"Mailing"List

The$key$in$making$great$and$
growable$systems$is$much$more$to$
design$how$its$modules$
communicate$rather$than$what$their$
internal$proper7es$and$behaviors$
should$be.
—"Alan"Kay2
2
"Squeak"Mailing"List

Protocol'oriented,programming,
focuses,on,interac4ons,rather,than,
object,hierarchies.
See#WWDC#2015#Session#408

Actor&Opera+ons4
1. Make'local'decisions
2. Create'other'actors
3. Send/receive'messages
4
"Wikipedia

Warning:(Flow(Charts(Ahead5
5
"XKCD"518

Typical(Actor(Flow

Example
Your%Code%as%a%Crime%Scene

Sequen&al)Processing

Concurrent)Processing

Parallel&Processing

Monad&Binding

Two$level(Aggrega-on

Interchangable,Parts

Other&Examples

Instagram

Deckset

LLVM6
6
"LLVM"for"Grad"Students

Automator

IFTTT

Workﬂow

Summary
1. The&Problems
2. Architecture&Theory
3. Examples
4. Demo

One$Final$Thought

The$Main$Thread$is$a$Singleton!
!!"!#!$!%

Demo

Ques%ons?

Resources(to(Learn(More
• WWDC%2015%Session%226
• Actor%Model
• Communica;ng%Sequen;al%Processes%(CSP)

In#Depth#Resources
• MapReduce
• Lambda-Architecture
• Reac3ve-Streams
• WWDC-2015-Session-408
• Amdahl's-Law

High level concurrency

Recommended

Recommended

More Related Content

What's hot

What's hot (18)

More from Robert Brown

More from Robert Brown (14)

Recently uploaded

Recently uploaded (20)

High level concurrency