Parallel Performance Toolsin Visual Studio 2010Hazim ShafiArchitect, Parallel Computing PlatformMicrosoft

Outline

Motivation Brief introduction to VS2010 parallel

computing technologies Overview of performance tools Demo

Motivation (1 of 2)

Multi-core processors are here Exploiting parallelism is becoming critical

for performance Enables compute-intensive scenarios

Developer Challenges Identify candidates for parallelization Performance tuning of parallel apps

Reasoning about the performance of multithreaded applications is difficult

This is not a new problem, but is exacerbated by the multi-core shift

Motivation (2 of 2) Profiling tools need enhancements

Temporal relationships Interactions with OS, libraries, I/O Visualization can be valuable Focus on parallel execution

Primary Goals Improve productivity of parallel

development and performance tuning Native and managed support Windows Vista, Windows Server 2008,

Windows 7, and Windows Server 2008 R2 32-bit and 64-bit

Visual Studio 2010Tools / Programming Models / Runtimes

Parallel Pattern Library

Resource Manager

Task Scheduler

Task Parallel Library

PLINQ

Managed Native Key:

ThreadsOperating System

Concurrency Runtime

Programming Models

Agents

Library

Thread PoolTask Scheduler

Resource Manager

Data

Stru

cture

s Data

Str

uct

ure

s

Tools

Tools

ParallelDebugger Toolwindo

ws

Profiler Concurrenc

yAnalysis

Detailed Goals

Identify opportunities for parallelism Expose causes of inefficiency Reach out to non-expert developers Provide actionable data by linking

behavior to source code when possible

IDE integration allows more efficient performance tuning

Key Features

Concurrency analysis Thread blocking analysis Thread migration and core utilization Inter-thread dependencies Multi-process scenario support

Typical Uses

Identifying opportunities for parallelism CPU-bound phases – speedup Synchronous I/O – hide latency

Improving parallel performance Load balancing Synchronization NUMA cache effects, thread migrations

(Server scenarios usually) Application responsiveness (hiding

latency)

Concurrency View (1 of 2)

Purpose: Learn or confirm the degree of

concurrency in a particular scenario Tune or determine opportunities for

parallelism Understand the degree of CPU contention

with other processes Use as an entry-point into more detailed

analysis

Concurrency View (2 of 2) How?

Core utilization for process over time Number of idle cores Number of cores used by “System”

process Number of cores used by “other”

processes

Thread Blocking Analysis (1 of 2) Purpose:

Assist developers in understanding the causes of thread blocking events

Provide actionable information to allow users to act upon some problems

Aggregate costs of blocking call stacks

Thread Blocking Analysis (2 of 2) How?

Threads as swim lanes (channels) in a timeline

Map thread state to a category Disk accesses with associated files and

delays For each blocking event

Display root cause when possible with call stack and delay duration

Provide various summary reports/stats

Thread Migration (1 of 2)

Purpose: Inform user when threads exhibit a large

number of thread migrations across cores Verify thread affinity impact on actual

execution Threads contending for a core while others

cores are available Allow users to identify a region of

interest: Threads exhibiting poor behavior Region in time Use the thread blocking view to drill into root

causes

Thread Migration (2 of 2)

How? Cores as swim lanes in a timeline view Associate a color per thread on the

timeline Show how threads execute on cores Display statistics

Inter-Thread Dependencies (1 of 2) Purpose:

Allow developers to understand inter-thread dependencies by exposing “blocker” to “blocked” thread relationships

Provide actionable data to correlate dependencies to code involved Sometimes, the dependency is a long chain

Inter-Thread Dependencies (2 of 2) How?

Modified thread blocking view, with “unblocking” events displayed and lines connecting dependent threads

Users can follow a dependence chain using the timeline user interface

Call stack of blocking thread shown in selection tab when available

VS2010 Parallel Performance Analysis

Demo

Simple Usage Scenario

Call to Action

We need your feedback on tools Download Visual Studio Team System

Beta 1 http://go.microsoft.com/fwlink/?LinkId=14740

7 Resources:

http://www.msdn.com/concurrency http://channel9.msdn.com/tags/pdc2008.par

allelism Contact:

http://blogs.msdn.com/hshafi

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