1. Tech Ed North America 2010
6/20/2018 7:07 AM
Required Slide
SESSION CODE: DEV317
Profiling and Debugging Parallel Code with Microsoft Visual Studio 2010
Huseyin Yildiz
Software Design Engineer
Microsoft Corporation
© 2010 Microsoft Corporation. All rights reserved. Microsoft, Windows, Windows Vista and other product names are or may be registered trademarks and/or trademarks in the U.S. and/or other countries.
The information herein is for informational purposes only and represents the current view of Microsoft Corporation as of the date of this presentation. Because Microsoft must respond to changing market conditions, it should not be interpreted to be a commitment on the part of Microsoft, and Microsoft cannot guarantee the accuracy of any information provided after the date of this presentation. MICROSOFT MAKES NO WARRANTIES, EXPRESS, IMPLIED OR STATUTORY, AS TO THE INFORMATION IN THIS PRESENTATION.

2. AGENDA
Motivation
Recap of Parallel Programming support in Visual Studio 2010
Parallel Profiling
Parallel Debugging

3. MOTIVATION Multicore processors are here
Single thread performance is mostly flat
Performance burden shifted to software
Parallelism libraries now available, and make the job easier
Data parallelism, task parallelism, parallel loops, agents
Concurrency opens up new challenges for debugging and tuning
=> Need for targeted tools

4. CONCURRENCY DEVELOPMENT CYCLE
Divide & conquer
Express Parallelism
Debug
Tune
- Isolate phases
- Identify parallelism opportunities
- Data parallelism
- Task parallelism
- Parallel loops
- Remove parallelism blockers
- Reduce latency
- Find more parallelism opportunities

5. PARALLELISM SUPPORT IN VISUAL STUDIO 2010
Tech Ed North America 2010
6/20/2018 7:07 AM
PARALLELISM SUPPORT IN VISUAL STUDIO 2010
Tools
Programming models
PLINQ
Parallel Pattern Library
Agents
Library
Parallel
Debugger
Task Parallel Library
Data structures
Data structures
Concurrency runtimes
Concurrency Visualizer
Task Scheduler
Task Scheduler
Thread Pool
Resource manager
Resource Manager
Operating system
Threads
Key:
Managed library
Native library
Tools
© 2010 Microsoft Corporation. All rights reserved. Microsoft, Windows, Windows Vista and other product names are or may be registered trademarks and/or trademarks in the U.S. and/or other countries.
The information herein is for informational purposes only and represents the current view of Microsoft Corporation as of the date of this presentation. Because Microsoft must respond to changing market conditions, it should not be interpreted to be a commitment on the part of Microsoft, and Microsoft cannot guarantee the accuracy of any information provided after the date of this presentation. MICROSOFT MAKES NO WARRANTIES, EXPRESS, IMPLIED OR STATUTORY, AS TO THE INFORMATION IN THIS PRESENTATION.

6. PARALLEL PROFILING Tech Ed North America 2010 6/20/2018 7:07 AM
© 2010 Microsoft Corporation. All rights reserved. Microsoft, Windows, Windows Vista and other product names are or may be registered trademarks and/or trademarks in the U.S. and/or other countries.
The information herein is for informational purposes only and represents the current view of Microsoft Corporation as of the date of this presentation. Because Microsoft must respond to changing market conditions, it should not be interpreted to be a commitment on the part of Microsoft, and Microsoft cannot guarantee the accuracy of any information provided after the date of this presentation. MICROSOFT MAKES NO WARRANTIES, EXPRESS, IMPLIED OR STATUTORY, AS TO THE INFORMATION IN THIS PRESENTATION.

7. CONCURRENCY VISUALIZER OVERVIEW
New concurrency-oriented profiler in Visual Studio 2010
Visualizes thread activity on a timeline
Per-thread or per-core views of execution states, blocking, I/O etc.
Provides very fine grained information
Zoom in to individual context switches to track suspicious interactions
Or zoom out to look for patterns (good or bad)

8. A STORY BETTER TOLD IN PICTURES

9. CONCURRENCY VISUALIZER OVERVIEW (cont’d)
Sampling profiler, also utilizes existing kernel level event sources
Based on ETW technology => very low overhead
Not tied to a specific concurrency runtime
Includes some visual markers specific to TPL, PPL, PLINQ
Supports
Native and managed apps
32-bit and 64-bit
Windows 7, Windows Server 2008, and Windows Vista

10. GETTING STARTED Run as admin Symbol paths OK?
Enable concurrency option in Performance Wizard

11. CPU UTILIZATION VIEW What it shows How to use it
High level graph of CPU utilization by your process
Y-axis covers all available cores
Comparison against other processes and idle time
How to use it
Good starting point for most concurrency profiling scenarios
Identify ranges or patterns of overall utilization
When was execution truly parallel? When did it get serialized?

12. THREAD VIEW What it shows How to use it
Each thread’s execution over time - down to context switches
Call stacks for where a thread got blocked and who unblocked it
Sampled call stacks (collected every 1 ms)
Disk I/O details on the same timeline
How to use it
Find root causes of low utilization and long delays
When a thread isn’t executing, find out why
Blocked? Paging? Preempted? Sleeping?
Analyze thread interactions

13. CORE VIEW What it shows How to use Execution activity per core
Individual threads identifiable by color
Core migration statistics
How to use
Identify thread affinity or migration issues
Unintended feature: Hunt for garbage collections!

14. Parallel Profiling Case Study
Tech Ed North America 2010
6/20/2018 7:07 AM
Parallel Profiling Case Study
DEMO
© 2010 Microsoft Corporation. All rights reserved. Microsoft, Windows, Windows Vista and other product names are or may be registered trademarks and/or trademarks in the U.S. and/or other countries.
The information herein is for informational purposes only and represents the current view of Microsoft Corporation as of the date of this presentation. Because Microsoft must respond to changing market conditions, it should not be interpreted to be a commitment on the part of Microsoft, and Microsoft cannot guarantee the accuracy of any information provided after the date of this presentation. MICROSOFT MAKES NO WARRANTIES, EXPRESS, IMPLIED OR STATUTORY, AS TO THE INFORMATION IN THIS PRESENTATION.

15. PATTERNS: SERIALIZATION
Problem: Too much synchronization in parallelized code
Signs: Little or no overlapping execution blocks, too frequent blocking
Solution: Identify contended lock from blocking call stacks, reduce locking

16. PATTERNS: UNEVEN WORK DISTRIBUTION
Problem: DOP decreases towards the end due to high work granularity
Signs: Staircase pattern in a group of related threads as work acquiesces
Solution: Revisit work partitioning

17. PATTERNS: OVERSUBSCRIPTION
Problem: Too many active threads competing for CPU time
Signs: Checkerboard pattern of execution and preemption blocks
Solution: Limit degree of parallelism

18. PATTERNS: INEFFICIENT I/O
Problem: Too much concurrent I/O blocks CPU bound work
Signs: Interleaved execution and I/O blocks
Solution: Revisit I/O strategy, consider asynchronous I/O

19. CUSTOM MARKERS FOR APPLICATION PHASES
#include "Scenario.h"
int _tmain(int argc, _TCHAR* argv[]) {
...
myScenario = new Scenario(0, L"Scenario Marker Example", (LONG) 0);
myScenario->Begin(0, TEXT(“PHASE1"));
// Do actual work for phase 1 here
myScenario->End(0, TEXT(“PHASE1")); }
Native and managed scenario marker libraries available at

20. PARALLEL DEBUGGING Tech Ed North America 2010 6/20/2018 7:07 AM
© 2010 Microsoft Corporation. All rights reserved. Microsoft, Windows, Windows Vista and other product names are or may be registered trademarks and/or trademarks in the U.S. and/or other countries.
The information herein is for informational purposes only and represents the current view of Microsoft Corporation as of the date of this presentation. Because Microsoft must respond to changing market conditions, it should not be interpreted to be a commitment on the part of Microsoft, and Microsoft cannot guarantee the accuracy of any information provided after the date of this presentation. MICROSOFT MAKES NO WARRANTIES, EXPRESS, IMPLIED OR STATUTORY, AS TO THE INFORMATION IN THIS PRESENTATION.

21. PARALLEL DEBUGGER OVERVIEW
Goal: Help navigate pending and active tasks in the debugger for TPL and PPL applications
Two new debugger tool windows:
“Parallel Tasks”
“Parallel Stacks”
Works with native and managed task runtimes
Task Parallel Library
Parallel Patterns Library

22. PARALLEL TASKS WINDOW List of all unfinished tasks
Which threads they are running on, call stacks
Which tasks are blocked, or waiting to run

23. PARALLEL STACKS WINDOW
Zoom control
Bird’s eye view
Multiple call stacks in a single view
Task status
Easy navigation to any executing method
Rich UI (zooming, panning, bird’s eye view, flagging, tooltips)

24. OTHER DEBUGGING ENHANCEMENTS
DebuggerDisplay and DebuggerProxy attributes for most new managed parallelism-related types
Task ,TaskScheduler
AggregateException
Concurrent collections
New synchronization primitives
Lazy<T> , ThreadLocal<T> …
Historical debugging (IntelliTrace) support for Task, QUWI and LazyInitializer

25. Parallel Debugger in Action
Tech Ed North America 2010
6/20/2018 7:07 AM
Parallel Debugger in Action
DEMO
© 2010 Microsoft Corporation. All rights reserved. Microsoft, Windows, Windows Vista and other product names are or may be registered trademarks and/or trademarks in the U.S. and/or other countries.
The information herein is for informational purposes only and represents the current view of Microsoft Corporation as of the date of this presentation. Because Microsoft must respond to changing market conditions, it should not be interpreted to be a commitment on the part of Microsoft, and Microsoft cannot guarantee the accuracy of any information provided after the date of this presentation. MICROSOFT MAKES NO WARRANTIES, EXPRESS, IMPLIED OR STATUTORY, AS TO THE INFORMATION IN THIS PRESENTATION.

26. RESOURCES
MSDN Parallel Computing Dev Center:
Team blog:
Hazim Shafi’s blog:
MSDN article on Concurrency Visualizer:
Scenario marker API:

27. Required Slide
Track PMs will supply the content for this slide, which will be inserted during the final scrub.
Tech Ed North America 2010
6/20/2018 7:07 AM
Track Resources
Visual Studio –
Soma’s Blog –
MSDN Data Developer Center –
ADO.NET Team Blog –
WCF Data Services Team Blog –
EF Design Blog –
© 2010 Microsoft Corporation. All rights reserved. Microsoft, Windows, Windows Vista and other product names are or may be registered trademarks and/or trademarks in the U.S. and/or other countries.
The information herein is for informational purposes only and represents the current view of Microsoft Corporation as of the date of this presentation. Because Microsoft must respond to changing market conditions, it should not be interpreted to be a commitment on the part of Microsoft, and Microsoft cannot guarantee the accuracy of any information provided after the date of this presentation. MICROSOFT MAKES NO WARRANTIES, EXPRESS, IMPLIED OR STATUTORY, AS TO THE INFORMATION IN THIS PRESENTATION.

28. Resources Learning Required Slide www.microsoft.com/teched
Tech Ed North America 2010
6/20/2018 7:07 AM
Required Slide
Resources
Learning
Sessions On-Demand & Community
Microsoft Certification & Training Resources
Resources for IT Professionals
Resources for Developers
© 2010 Microsoft Corporation. All rights reserved. Microsoft, Windows, Windows Vista and other product names are or may be registered trademarks and/or trademarks in the U.S. and/or other countries.
The information herein is for informational purposes only and represents the current view of Microsoft Corporation as of the date of this presentation. Because Microsoft must respond to changing market conditions, it should not be interpreted to be a commitment on the part of Microsoft, and Microsoft cannot guarantee the accuracy of any information provided after the date of this presentation. MICROSOFT MAKES NO WARRANTIES, EXPRESS, IMPLIED OR STATUTORY, AS TO THE INFORMATION IN THIS PRESENTATION.

29. Complete an evaluation on CommNet and enter to win!
Tech Ed North America 2010
6/20/2018 7:07 AM
Required Slide
Complete an evaluation on CommNet and enter to win!
© 2010 Microsoft Corporation. All rights reserved. Microsoft, Windows, Windows Vista and other product names are or may be registered trademarks and/or trademarks in the U.S. and/or other countries.
The information herein is for informational purposes only and represents the current view of Microsoft Corporation as of the date of this presentation. Because Microsoft must respond to changing market conditions, it should not be interpreted to be a commitment on the part of Microsoft, and Microsoft cannot guarantee the accuracy of any information provided after the date of this presentation. MICROSOFT MAKES NO WARRANTIES, EXPRESS, IMPLIED OR STATUTORY, AS TO THE INFORMATION IN THIS PRESENTATION.

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31. Tech Ed North America 2010 6/20/2018 7:07 AM
© 2010 Microsoft Corporation. All rights reserved. Microsoft, Windows, Windows Vista and other product names are or may be registered trademarks and/or trademarks in the U.S. and/or other countries.
The information herein is for informational purposes only and represents the current view of Microsoft Corporation as of the date of this presentation. Because Microsoft must respond to changing market conditions, it should not be interpreted to be a commitment on the part of Microsoft, and Microsoft cannot guarantee the accuracy of any information provided after the date of this presentation. MICROSOFT MAKES NO WARRANTIES, EXPRESS, IMPLIED OR STATUTORY, AS TO THE INFORMATION IN THIS PRESENTATION.
© 2010 Microsoft Corporation. All rights reserved. Microsoft, Windows, Windows Vista and other product names are or may be registered trademarks and/or trademarks in the U.S. and/or other countries.
The information herein is for informational purposes only and represents the current view of Microsoft Corporation as of the date of this presentation. Because Microsoft must respond to changing market conditions, it should not be interpreted to be a commitment on the part of Microsoft, and Microsoft cannot guarantee the accuracy of any information provided after the date of this presentation. MICROSOFT MAKES NO WARRANTIES, EXPRESS, IMPLIED OR STATUTORY, AS TO THE INFORMATION IN THIS PRESENTATION.

32. CPU UTILIZATION VIEW CLOSE-UP
Number of cores
CPU Utilization of other processes
CPU Utilization of the target process
Idle time

33. THREAD VIEW CLOSE-UP Zoom control and time axis
Ruler tool for custom time measurements
One lane per thread
Thread activity (color coded execution states)
Usage Hints
Activity Legend
Call Stacks available for each “sample”
Who unblocked this thread?

34. CORE VIEW CLOSE-UP Execution on each core One lane per logical core
One color per thread
Cross-core migration statistics

35. Required Slide Tech Ed North America 2010 6/20/2018 7:07 AM
© 2010 Microsoft Corporation. All rights reserved. Microsoft, Windows, Windows Vista and other product names are or may be registered trademarks and/or trademarks in the U.S. and/or other countries.
The information herein is for informational purposes only and represents the current view of Microsoft Corporation as of the date of this presentation. Because Microsoft must respond to changing market conditions, it should not be interpreted to be a commitment on the part of Microsoft, and Microsoft cannot guarantee the accuracy of any information provided after the date of this presentation. MICROSOFT MAKES NO WARRANTIES, EXPRESS, IMPLIED OR STATUTORY, AS TO THE INFORMATION IN THIS PRESENTATION.