Igor Ostrovsky Software Engineer Microsoft Corporation

Parallel Programming with the .NET Framework 4 and Visual Studio 2010

Introducing

Agenda

Why

What Managed APIs/runtime (.NET 4)

Tools (in the VS2010 IDE)

Why The Manycore Shift

Why Problem and Goals

Free lunch is over

How much will you pay?

Multithreaded programming is hard today

Goals Developer productivity

Performance

Agenda Checkpoint

Why

What Managed APIs/runtime (.NET 4)

a.k.a. Parallel Extensions to .NET

Tools (in the VS2010 IDE)

Parallel Extensions to .NET Overview

Pure .NET libraries

Feature areas Task Parallel Library (TPL)

Parallel LINQ (PLINQ)

Thread-safe data structures and synchronization primitives

Enhanced ThreadPool

Parallel.For(0, N, i => { Compute(i); }); Parallel.ForEach(data, e => Compute(e));

Task Parallel Library (TPL) Loops

for (int i = 0; i < N; i++) { Compute(i); } foreach (T e in data) Compute(e);

Task Parallel Library (TPL) Loops

DEMO: Raytracer

ParallelOptions pops = new ParallelOptions()

{

MaxDegreeOfParallelism = 2,

CancellationToken = myToken

};

Parallel.Invoke(pops,

() => A(),

() => B(),

() => C());

Task Parallel Library (TPL) Regions

A(); B(); C();

Task Parallel Library (TPL) Tasks

DEMO: Task examples DEMO: Reversi

Parallel LINQ (PLINQ) Language Integrated Query (LINQ) Overview

Visual Basic C# Others…

.NET Standard Query Operators

LINQ-enabled data sources

LINQ To Objects

LINQ To XML

LINQ To …

.AsParallel().WithDegreeOfParallelism(4) .WithCancellation(myToken) .WithMergeOptions(ParallelMergeOptions.NotBuffered) .WithExecutionMode(ParallelExecutionMode.ForceParallelism)

Parallel LINQ (PLINQ) LINQ-To-Objects Parallelized

var results = from i in arrayOfIntegers where i % 2 == 0 select i;

var results = from i in arrayOfIntegers.AsParallel() where i % 2 == 0 select i;

Aggregate(3)

All(1)

Any(2)

AsEnumerable(1)

Average(20)

Cast(1)

Concat(1)

Contains(2)

Count(2)

DefaultIfEmpty(2)

Distinct(2)

ElementAt(1)

ElementAtOrDefault(1)

Empty(1)

Except(2)

First(2)

FirstOrDefault(2)

GroupBy(8)

GroupJoin(2)

Intersect(2)

Join(2)

Last(2)

LastOrDefault(2)

LongCount(2)

Max(22)

Min(22)

OfType(1)

OrderBy(2)

OrderByDescending(2)

Range(1)

Repeat(1)

Reverse(1)

Select(2)

SelectMany(4)

SequenceEqual(2)

Single(2)

SingleOrDefault(2)

Skip(1)

SkipWhile(2)

Sum(20)

Take(1)

TakeWhile(2)

ThenBy(2)

ThenByDescending(2)

ToArray(1)

ToDictionary(4)

ToList(1)

ToLookup(4)

Union(2)

Where(2)

Zip(1)

In .NET 4, ~50 operators w/ ~175 overloads

Parallel LINQ (PLINQ) Supported Operators

Parallel LINQ (PLINQ)

DEMO: Baby Names

Thread-safe Data Structures and Sync Primitives

Thread-safe, scalable collections IProducerConsumerCollection<T>

ConcurrentQueue<T> ConcurrentStack<T> ConcurrentBag<T>

ConcurrentDictionary<TKey, TValue>

Phases and work exchange

Barrier BlockingCollection<T> CountdownEvent

Partitioning

{Orderable}Partitioner<T> Partitioner.Create(…)

Initialization

Lazy<T>

ThreadLocal<T>

Locks

ManualResetEventSlim

SemaphoreSlim

SpinLock

SpinWait

Cancellation

CancellationTokenSource

CancellationToken

ThreadPool in .NET 3.5

Global Queue

Worker Thread 0

Worker Thread N

…

Other Threads

Work Item 3

Work Item 2 Work Item 1

ThreadPool in .NET 4

Lock-free Global Queue

Worker Thread 0

Worker Thread N

…

Other Threads

Local Work-

Stealing Queue

Local Work-

Stealing Queue

Work Item 3 Work Item 4 Work Item 5

Work Item 2 Work Item 1

Agenda Checkpoint

Why

What Managed APIs/runtime (.NET 4)

a.k.a. Parallel Extensions to .NET

Tools (in the VS2010 IDE) Debugging: Parallel Tasks and Parallel Stacks

Concurrency Visualizer

Tools Parallel Debugging

Two new debugger toolwindows

“Parallel Tasks”

“Parallel Stacks”

Tools “Parallel Tasks”

What threads are executing my Tasks? Where are my Tasks running (location, call stack)? What is the status of my Tasks?

Tools “Parallel Stacks”

Multiple call stacks in a single view Easy navigation to any executing method Rich UI (zooming, panning, tooltips, etc.)

Zoom

control Bird’s eye view

Tools Concurrency Visualizer

Tools Concurrency Visualizer: CPU Utilization View

Number of cores

Your Process

Idle Time

Other Processes

Tools Concurrency Visualizer: Threads View

Hide Uninteresting

threads

Active Legend

Call Stacks

Usage Hints

Measure time for interesting

segments

Tools Concurrency Visualizer: Cores View

Migration visualization

Color per thread

Related Content

Dev Center: http://msdn.microsoft.com/concurrency

Forum: http://social.msdn.microsoft.com/Forums/en-US/parallelextensions/threads

Blog: http://blogs.msdn.com/pfxteam/

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