Exploiting the computing power of the diversity of resources available on heterogeneous
systems is mandatory but a very challenging task. The diversity of architectures, execution
models and programming tools, together with disjoint address spaces and di erent
computing capabilities, raise a number of challenges that severely impact on application
performance and programming productivity. This problem is further compounded in the
presence of data parallel irregular applications.
This paper presents a framework that addresses development and execution of data
parallel irregular applications in heterogeneous systems. A uni ed task-based programming
and execution model is proposed, together with inter and intra-device scheduling,
which, coupled with a data management system, aim to achieve performance scalability
across multiple devices, while maintaining high programming productivity. Intradevice
scheduling on wide SIMD/SIMT architectures resorts to consumer-producer kernels,
which, by allowing dynamic generation and rescheduling of new work units, enable
balancing irregular workloads and increase resource utilization.
Results show that regular and irregular applications scale well with the number of
devices, while requiring minimal programming e ort. Consumer-producer kernels are
able to sustain signi cant performance gains as long as the workload per basic work
unit is enough to compensate overheads associated with intra-device scheduling. This
not being the case, consumer kernels can still be used for the irregular application.
Comparisons with an alternative framework, StarPU, which targets regular workloads,
consistently demonstrate signi cant speedups. This is, to the best of our knowledge, the
rst published integrated approach that successfully handles irregular workloads over
heterogeneous systems.This work is funded by National Funds through the FCT - Fundação para a Ciência
e a Tecnologia (Portuguese Foundation for Science and Technology) and by ERDF -
European Regional Development Fund through the COMPETE Programme (operational
programme for competitiveness) within projects PEst-OE/EEI/UI0752/2014
and FCOMP-01-0124-FEDER-010067. Also by the School of Engineering, Universidade
do Minho within project P2SHOCS - Performance Portability on Scalable
Heterogeneous Computing Systems
