Debugging CUDA applications

Debugging CUDA applications

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  1© 2017 RogueWave Software, Inc. All Rights Reserved. 1 Debugging CUDA applications GPU Technology Conference Roundtable discussions
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  2© 2017 RogueWave Software, Inc. All Rights Reserved. 2 Complexity in debugging CUDA • Heavily parallel – Explosion in threads – Usage of MPI, OpenMP, OpenACC • Used together • Complex platforms – CPUs with GPUs many times mixed • Multiple languages being used – Python for ease of use – C/C++ for speed and legacy algorithms – The data passing and glue code adds complexity
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  3© 2017 RogueWave Software, Inc. All Rights Reserved. 3 Directive languages + GPUs debugging • OpenMP 4 debugging support (CPUs and GPUs) for Sierra • Collaborate on OpenMP Debug API (OMPD) design • Three phases – Phase 1: OMPD: OMP3.1/CPU, x86_64 – Phase 2: OMPD: OMP4/CPU/GPU, x86_64 – Phase 3: OMPD: OMP4/CPU/GPU, PowerLE – Need compiler support to make it all work – OpenACC works always interested in user input
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  4© 2017 RogueWave Software, Inc. All Rights Reserved. 4 Current debugging advancements Debugging multiple processes needs to be exclusive Support one debug process per GPU
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  5© 2017 RogueWave Software, Inc. All Rights Reserved. 5 Python with filtering Python code available by choosing the stack frame Program counter shows where the call was made from in Python Come on Thursday to S7506 - ROLLING IN THE DEEP for details
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  6© 2017 RogueWave Software, Inc. All Rights Reserved. 6 TotalView for the NVIDIA ® GPU Accelerator • TotalView – Leading debugger for multi- threaded issues at scale • CUDA 8.0 • Cray, OpenPOWER, Linux, OpenACC • Compiler: GCC, PGI • Features and capabilities include – MPI-based clusters – Flexible Display and Navigation – Memory address spaces – Leverages CUDA memcheck – CUDA dynamic parallelism © 2015 ROGUE WAVE SOFTWARE, INC. ALL RIGHTS RESERVED
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  7© 2017 RogueWave Software, Inc. All Rights Reserved. 7 Interested in learning more about TotalView for HPC: www.roguewave.com
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  8© 2017 RogueWave Software, Inc. All Rights Reserved. 8
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  9© 2017 RogueWave Software, Inc. All Rights Reserved. 9 TotalView for HPC • Comprehensive 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 • Track memory leaks in running applications • Supports C/C++ on Linux • Allowing the business to have – Predictable development schedules – Less time spent debugging