Download intel parallel inspector

2006, Intel Corporation. All rights reserved. Intel and the Intel logo are trademarks or registered trademarks of Intel Corporation or its subsidiaries in the United States or other countries. *Other brands and names are the property of their respective owners. 11 Intel® Parallel Inspector Binary Instrumentation Build with supported compiler Running the application Must be run from within Parallel Inspector Application is instrumented when executed External DLLs are instrumented as used 12 Copyright © 2006, Intel Corporation. All rights reserved. Intel and the Intel logo are trademarks or registered trademarks of Intel Corporation or its subsidiaries in the United States or other countries. *Other brands and names are the property of their respective owners. Starting Parallel Inspector Build the Debug version of the application with appropriate flags set 12 Intel® Parallel Inspector 13 Copyright © 2006, Intel Corporation. All rights reserved. Intel and the Intel logo are trademarks or registered trademarks of Intel Corporation or its subsidiaries in the United States or other countries. *Other brands and names are the property of their respective owners. Starting Parallel Inspector Select Parallel Inspector from the Tools menu 13 Intel® Parallel Inspector You can choose to look for Memory Errors Threading Errors 14 Copyright © 2006, Intel Corporation. All rights reserved. Intel and the Intel logo are trademarks or registered trademarks of Intel Corporation or its subsidiaries in the United States or other countries. *Other brands and names are the property of their respective owners. Starting Parallel Inspector The Configure Analysis window pops up 14 Intel® Parallel Inspector Select the level of analysis to be carried out by Parallel Inspector The deeper the analysis, the more thorough the results and the longer the execution time Click Run Analysis 15 Copyright © 2006, Intel Corporation. All rights reserved. Intel and the Intel logo are trademarks or registered trademarks of Intel Corporation or its subsidiaries in the United States or other countries. *Other brands and names are the property of their respective owners. Starting Parallel Inspector The initial (raw) results come up after analysis 15 Intel® Parallel Inspector Click the Interpret Results button to filter the raw data into more human consumable formats 16 Copyright © 2006, Intel Corporation. All rights reserved. Intel and the Intel logo are trademarks or registered trademarks of Intel Corporation or its subsidiaries in the United States or other countries. *Other brands and names are the property of their respective

Owners. Starting Parallel Inspector The analysis results are gathered together in related categories 16 Intel® Parallel Inspector Double-click a line from the Problem Sets pane to see the source code that generated the diagnostic 17 Copyright © 2006, Intel Corporation. All rights reserved. Intel and the Intel logo are trademarks or registered trademarks of Intel Corporation or its subsidiaries in the United States or other countries. *Other brands and names are the property of their respective owners. Starting Parallel Inspector The source lines involved in a data race can be shown 17 Intel® Parallel Inspector 18 Copyright © 2006, Intel Corporation. All rights reserved. Intel and the Intel logo are trademarks or registered trademarks of Intel Corporation or its subsidiaries in the United States or other countries. *Other brands and names are the property of their respective owners. 18 Intel® Parallel Inspector Activity 1a - Potential Energy Build and run serial version Build threaded version Run application in Parallel Inspector to identify threading problems 19 Copyright © 2006, Intel Corporation. All rights reserved. Intel and the Intel logo are trademarks or registered trademarks of Intel Corporation or its subsidiaries in the United States or other countries. *Other brands and names are the property of their respective owners. 19 Intel® Parallel Inspector Race Conditions Execution order is assumed but cannot be guaranteed Concurrent access of same variable by multiple threads Most common error in multithreaded programs May not be apparent at all times 20 Copyright © 2006, Intel Corporation. All rights reserved. Intel and the Intel logo are trademarks or registered trademarks of Intel Corporation or its subsidiaries in the United States or other countries. *Other brands and names are the property of their respective owners. 20 Intel® Parallel Inspector Solving Race Conditions Solution: Scope variables to be local to threads When to use Value computed is not used outside parallel region Temporary or “work” variables How to implement OpenMP scoping clauses ( private, shared ) Declare variables within threaded functions Allocate variables on thread stack TLS (Thread Local Storage) API 21 Copyright © 2006, Intel Corporation. All rights reserved. Intel and the Intel logo are trademarks or registered trademarks of Intel Corporation or its subsidiaries in the United States or other countries. *Other brands and names are the property of their respective owners. 21 Intel® Parallel Inspector Solving Race Conditions Solution: Control shared access with critical regions When to use

Presentation on theme: "Correcting Threading Errors with Intel® Parallel Inspector."— Presentation transcript: 1 Correcting Threading Errors with Intel® Parallel Inspector 2 Copyright © 2006, Intel Corporation. All rights reserved. Intel and the Intel logo are trademarks or registered trademarks of Intel Corporation or its subsidiaries in the United States or other countries. *Other brands and names are the property of their respective owners. 2 Intel® Parallel Inspector Objectives After successful completion of this module you will be able to… Use Parallel Inspector to detect and identify a variety of threading correctness issues in threaded applications Determine if library functions are thread-safe 3 Copyright © 2006, Intel Corporation. All rights reserved. Intel and the Intel logo are trademarks or registered trademarks of Intel Corporation or its subsidiaries in the United States or other countries. *Other brands and names are the property of their respective owners. 3 Intel® Parallel Inspector Agenda What is Intel® Parallel Inspector? Detecting race conditions Detecting potential for deadlock Checking library thread-safety 4 Copyright © 2006, Intel Corporation. All rights reserved. Intel and the Intel logo are trademarks or registered trademarks of Intel Corporation or its subsidiaries in the United States or other countries. *Other brands and names are the property of their respective owners. 4 Intel® Parallel Inspector Motivation Developing threaded applications can be a complex task New class of problems are caused by the interaction between concurrent threads Data races or storage conflicts More than one thread accesses memory without synchronization Deadlocks Thread waits for an event that will never happen 5 Copyright © 2006, Intel Corporation. All rights reserved. Intel and the Intel logo are trademarks or registered trademarks of Intel Corporation or its subsidiaries in the United States or other countries. *Other brands and names are the property of their respective owners. 5 Intel® Parallel Inspector Debugging tool for threaded software Plug-in to Microsoft* Visual Studio* Finds threading bugs in OpenMP*, Intel® Threading Building Blocks, and Win32* threaded software Locates bugs quickly that can take days to find using traditional methods and tools Isolates problems, not the symptoms Bug does not have to occur to find it! 6 Copyright © 2006, Intel Corporation. All rights reserved. Intel and the Intel logo are trademarks or registered trademarks of Intel Corporation or its subsidiaries in the United States or other countries. *Other brands and names are the property of their respective owners. Intel® Parallel Inspector Features

Integrated into Microsoft Visual Studio.NET* IDE 2005 & 2008 Editions Supports different compilers Microsoft* Visual* C++.NET* Intel Parallel Composer View (drill-down to) source code for Diagnostics One-click help for diagnostics Possible causes and solution suggestions 6 Intel® Parallel Inspector 7 Copyright © 2006, Intel Corporation. All rights reserved. Intel and the Intel logo are trademarks or registered trademarks of Intel Corporation or its subsidiaries in the United States or other countries. *Other brands and names are the property of their respective owners. 7 Intel® Parallel Inspector Parallel Inspector: Analysis Dynamic as software runs Data (workload) -driven execution Includes monitoring of: Thread and Sync APIs used Thread execution order Scheduler impacts results Memory accesses between threads Code path must be executed to be analyzed 8 Copyright © 2006, Intel Corporation. All rights reserved. Intel and the Intel logo are trademarks or registered trademarks of Intel Corporation or its subsidiaries in the United States or other countries. *Other brands and names are the property of their respective owners. 8 Intel® Parallel Inspector Parallel Inspector: Before You Start Instrumentation: background Adds calls to library to record information Thread and Sync APIs Memory accesses Increases execution time and size Use small data sets (workloads) Execution time and space is expanded Multiple runs over different paths yield best results Workload selection is important! 9 Copyright © 2006, Intel Corporation. All rights reserved. Intel and the Intel logo are trademarks or registered trademarks of Intel Corporation or its subsidiaries in the United States or other countries. *Other brands and names are the property of their respective owners. 9 Intel® Parallel Inspector Workload Guidelines Execute problem code once per thread to be identified Use smallest possible working data set Minimize data set size Smaller image sizes Minimize loop iterations or time steps Simulate minutes rather than days Minimize update rates Lower frames per second Finds threading errors faster! 10 Copyright © 2006, Intel Corporation. All rights reserved. Intel and the Intel logo are trademarks or registered trademarks of Intel Corporation or its subsidiaries in the United States or other countries. *Other brands and names are the property of their respective owners. 10 Intel® Parallel Inspector Building for Parallel Inspector Compile Use dynamically linked thread-safe runtime libraries ( /MDd ) Generate symbolic information ( /ZI ) Disable optimization ( /Od ) Link Preserve symbolic information ( /DEBUG ) Specify relocatable code sections ( /FIXED:NO ) 11 Copyright ©