PPoPP 2016
Sat 12 - Wed 16 March 2016 Barcelona, Spain
Wed 16 Mar 2016 12:00 - 12:25 at Mallorca+Menorca - Performance analysis and debugging Chair(s): Martin Schulz

Average programmers struggle to solve performance problems in OpenMP programs with tasks and parallel for-loops. Existing performance analysis tools visualize OpenMP task performance from the runtime system’s perspective where task execution is interleaved with other tasks in an unpredictable order. Problems with OpenMP parallel for-loops are similarly difficult to resolve since tools only visualize aggregate thread-level statistics such as load imbalance without zooming into a per-chunk granularity. The runtime system/threads oriented visualization provides poor support for understanding problems with task and chunk execution time, parallelism, and memory hierarchy utilization, forcing average programmers to rely on experts or use tedious trial-and-error tuning methods for performance. We present grain graphs, a new OpenMP performance analysis method that visualizes grains – computation performed by a task or a parallel for-loop chunk instance – and highlights problems such as low parallelism, work inflation and poor parallelization benefit at the grain level. We demonstrate that grain graphs can quickly reveal performance problems that are difficult to detect and characterize in fine detail using existing visualizations in standard OpenMP programs, simplifying OpenMP performance analysis. This enables average programmers to make portable optimizations for poor performing OpenMP programs, reducing pressure on experts and removing the need for tedious trial-and-error tuning.

Wed 16 Mar
Times are displayed in time zone: (GMT+01:00) Greenwich Mean Time : Belfast change

11:35 - 12:50: Main conference - Performance analysis and debugging at Mallorca+Menorca
Chair(s): Martin SchulzLawrence Livermore National Laboratory
PPoPP-2016-papers11:35 - 12:00
Georgios ChatzopoulosEcole Polytechnique Federale de Lausanne (EPFL), Switzerland, Aleksandar DragojevićMicrosoft Research, Rachid GuerraouiEPFL, Switzerland
Link to publication DOI
PPoPP-2016-papers12:00 - 12:25
Ananya Muddukrishna, Peter A. JonssonSICS Swedish ICT AB, Artur PodobasKTH Royal Institute of Technology, Mats BrorssonKTH Royal Institute of Technology
Link to publication DOI
PPoPP-2016-papers12:25 - 12:50
Nuno MachadoINESC-ID / Instituto Superior Técnico, Universidade de Lisboa, Brandon LuciaCarnegie Mellon University, Luís RodriguesUniversidade de Lisboa, Instituto Superior Técnico, INESC-ID
Link to publication DOI