Profiling and Optimizing for Xeon Phi with Allinea MAP
1 like530 views
Allinea's tools like MAP and DDT provide a unified development environment for profiling, debugging, and optimizing code running on Xeon Phi processors. MAP can show developers which loops are and aren't vectorized, and collects full profiling metrics directly on Xeon Phi cards. This helps identify optimization opportunities and ensures code is taking best advantage of the new architecture. The unified interface with DDT keeps developers productive whether profiling or debugging issues like OpenMP errors.
Profiling and Optimizing for Xeon Phi with Allinea MAP
- 1. Profiling and optimizing for Xeon Phi with Allinea MAP Discovering bottlenecks without pain
- 2. What is happening ? Single Core Era Multi-Core Era Many-Core Era Constraints : -Power -Complexity of algorithms Constraints : -Power -Parallel software availability -Scalability Constraints : -Programming models Performance Time(years)
- 3. • Parallel profiler designed for: ‒ C/C++, Fortran ‒ MPI code Interdependent or independent processes ‒ Multithreaded code Monitor the main threads for each process ‒ Accelerated codes GPUs, Intel Xeon Phi • Improve productivity : ‒ Helps you detect performance issues quickly and easily ‒ Tells you immediately where your time is spent in your source code ‒ Helps you to optimize your application efficiently Allinea MAP Increase application performance
- 4. • Support for I/O metrics ‒ I/O can be a major bottleneck in HPC systems ‒ Find the optimal configuration for your file system. Benefit : Broader profiling and analysis capabilities to solve even more performance issues. • Support for Intel Xeon Phi ‒ Already supported on Allinea DDT ‒ Officially extended to profiling Benefit : Ensure you are getting the best performance from new technology. Allinea MAP 4.1 New features at ISC 2013
- 5. Intel Xeon Phi and Allinea • Started architecture and tools discussions with Intel • Early development prototypes exchanged2011 • Full debugger support for Intel MIC architecture • Official 3.2 release • Feedback from early adopters2012 • Profiling support for Intel Xeon Phi announced • #1 Green 500 system, Xeon Phi-powered Beacon chooses Allinea • Dramatic surge in interest in debugging and profiling on Xeon Phi 2013
- 6. Optimizing for the Xeon Phi Where do you start? “Code that’s well-optimized for the host usually performs pretty well on the cards” - Pretty much everyone
- 7. Optimizing for the Xeon Phi But what matters? Vectorization Other stuff Performance
- 8. Optimizing for the Xeon Phi Is my code well-vectorized? … maybe?
- 9. Optimizing for the Xeon Phi Is my code well-vectorized? … maybe?
- 10. Optimizing for the Xeon Phi Is my code well-vectorized? … maybe? Not in this loop (16.5% of total time)
- 11. Optimizing for the Xeon Phi Non-obvious tradeoffs
- 12. Optimizing for the Xeon Phi Non-obvious tradeoffs Here a loop taking 55% of total runtime isn’t vectorized at all Taking the unvectorizable rand() out of the loop allows the sqrt workload to be fully-vectorized – reverse loop fusion!
- 13. Optimizing for the Xeon Phi Non-obvious tradeoffs Now the floating- point workload is fully-vectorized But all the time is being spent in the random number generation, so that’s what really needs to be optimized
- 14. Optimizing for the Xeon Phi Know your tools Replace rand() with Intel’s vectorized version and re-fuse the loop to retain temporal cache locality benefits
- 15. Optimizing for the Xeon Phi The full picture You need to see the full picture to spot these tradeoffs – Allinea MAP shows you the way
- 16. Optimizing for the Xeon Phi Running on the card Allinea MAP runs with full metrics on Xeon Phi cards!
- 17. Optimizing for the Xeon Phi Running on the card This makes it easy to compare and learn versus the host
- 18. • Full, graphical debugger designed for : ‒ C/C++, Fortran, Xeon Phi, UPC, … ‒ MPI, OpenMP and mixed-mode code • Unified interface with Allinea MAP : ‒ Just what you need when you’ve added OpenMP and now everything segfaults! ‒ One interface eliminates learning curve ‒ Spend more time on your results • Slash your time to develop : ‒ Reproduces and triggers your bugs instantly ‒ Helps you easily understand where issues come from quickly ‒ Helps you to fix them as swiftly as possible Allinea DDT Unified interface for debugging
- 19. • Ten years of high-quality development tools ‒ Leading in HPC software tools market worldwide ‒ Global customer base • Making parallel programming accessible to the widest range of scientists and programmers ‒ Design an unrivaled productive and easy-to-use development environment… ‒ … To help you reach the highest level of performance and scalability ‒ Define a new standard of customer support Allinea Software
- 20. Summary • Allinea’s tools are the premier Xeon Phi development environment – See at a glance which loops to vectorized and which to ignore – Full profiling metrics available on the Xeon Phi cards – Unified interface with Allinea DDT keeps you productive, whatever you’re working on To learn more, visit us at our booth #655 !
- 21. Thank you Your contacts : – Technical Support team : support@allinea.com – Sales team : sales@allinea.com