Approaches to debugging mixed-language HPC apps
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The document discusses the challenges of debugging mixed-language HPC applications, particularly with Python and C/C++. It highlights the importance of data modeling and various techniques for calling between languages, as well as debugging tools like TotalView for analyzing multi-threaded applications. Additionally, it mentions real-world applications and the benefits of using TotalView for effective debugging of complex systems.
Approaches to debugging mixed-language HPC apps
- 1. 1© 2017 Rogue Wave Software, Inc. All Rights Reserved. 1 Approaches to debugging mixed- language HPC apps Exhibitor Forum SC17
- 2. 2© 2017 Rogue Wave Software, Inc. All Rights Reserved. 2 Data modeling is critical for machine learning • Data scientists iterate over huge datasets • Legacy algorithms are critical • Most popular languages – R in scientific communities – Python in engineering • Focusing on Python • Developers use it because – Ease of use – Clean syntax – Extension libraries (many in C/C++)
- 3. 3© 2017 Rogue Wave Software, Inc. All Rights Reserved. 3 Calling C/C++ from Python • High performance libraries are written in C/C++ and Fortran – Run faster – Rewriting doesn’t make sense – Advanced multi-threaded capabilities • Fortunately there are many ways to call between the languages
- 4. 4© 2017 Rogue Wave Software, Inc. All Rights Reserved. 4 Debugging multiple languages • Debugging one language is difficult enough – Especially with many threads/processes • The language intersection is tougher – Data comparison – Glue code • Issues are: – Viewing data across language barriers – Combined call stack – Extraneous stack frames
- 5. 5© 2017 Rogue Wave Software, Inc. All Rights Reserved. 5 Python Session Editor Glue code Debugging Python Interpreter
- 6. 6© 2017 Rogue Wave Software, Inc. All Rights Reserved. 6 Stopped in C/C++ Python Extension Shows Python & C++
- 7. 7© 2017 Rogue Wave Software, Inc. All Rights Reserved. 7 Stopped in C/C++ Python Extension Shows Python & C++
- 8. 8© 2017 Rogue Wave Software, Inc. All Rights Reserved. 8 Selected Python frame C++ data Python Data
- 9. 9© 2017 Rogue Wave Software, Inc. All Rights Reserved. 9 Data View C++ data Python Data
- 10. 10© 2017 Rogue Wave Software, Inc. All Rights Reserved. 10 Numpy
- 11. 11© 2017 Rogue Wave Software, Inc. All Rights Reserved. 11 Python without filtering Glue code No viewing of Python data and code
- 12. 12© 2017 Rogue Wave Software, Inc. All Rights Reserved. 12 Python support in TotalView • Designed for where Python calls C/C++ or vice versa • Glue frames hidden from view – Supported for SWIG – User customizable • Python information shown – Code – Data
- 13. 13© 2017 Rogue Wave Software, Inc. All Rights Reserved. 13 Stack transformation facility • Hides stack frames • Transforms stack frames • Backbone for: – Python support • Useful for any stack frames you want to hide – Language differences – Wrapper code
- 14. 14© 2017 Rogue Wave Software, Inc. All Rights Reserved. 14 Demo
- 15. 15© 2017 Rogue Wave Software, Inc. All Rights Reserved. 15 Few use cases • Currently used with large scientific application at Lawrence Livermore National Laboratory • Helpful while learning or extending packages such as TensorFlow.
- 16. 16© 2017 Rogue Wave Software, Inc. All Rights Reserved. 16 TensorFlow basics • Open source • Numerical computation • Usage in machine learning • Written in C++ – Called from Python
- 17. 17© 2017 Rogue Wave Software, Inc. All Rights Reserved. 17 TensorFlow Multithreaded application Glue code removed Added a rule for some wrappers
- 18. 18© 2017 Rogue Wave Software, Inc. All Rights Reserved. 18 How does Rogue Wave help HPC? TotalView debugger • Troubleshooting and analysis tool • Visibility into applications • Control over applications • Integrated Reverse Debugging MemoryScape debugger • Malloc API misuse • Memory leaks • Buffer overflows • Invalid Read/Write
- 19. 19© 2017 Rogue Wave Software, Inc. All Rights Reserved. 19 TotalView for HPC • Comprehensive multi-core and multi-threaded analysis and debug environment – Thread specific breakpoints – Control individual thread execution – View thread specific stack and data – View complex data types easily • Integrated Reverse debugging • Mixed Language - Python C/C++ • Track memory leaks in running applications • Supports C/C++ on Linux • Active development for 30+ years • Allowing the business to have – Predictable development schedules – Less time spent debugging
- 20. 20© 2017 Rogue Wave Software, Inc. All Rights Reserved. 20 Summary • Comments and questions • Come see a live demo and learn more at our SC17 booth 1715 • For more information – https://www.roguewave.com – White Paper - https://www.roguewave.com/resources/white- papers/mixed-language-debugging-python-c-cplusplus – Videos - https://www.youtube.com/watch?v=LXSSstUdKnc – Evaluation - https://www.roguewave.com/products-services/request- evaluation
- 21. 21© 2017 Rogue Wave Software, Inc. All Rights Reserved. 21