The Uintah Framework: A Unified Heterogeneous Task Scheduling and Runtime System
Scientific Computing and Imaging Institute, University of Utah, Salt Lake City, UT 84112 USA
International Conference on High Performance Computing, Networking, Storage and Analysis (SC ’12), 2012
@article{meng2012uintah,
title={The Uintah Framework: A Unified Heterogeneous Task Scheduling and Runtime System},
author={Meng, Q. and Humphrey, A. and Berzins, M.},
year={2012}
}
The development of a new unified, multi-threaded runtime system for the execution of asynchronous tasks on heterogeneous systems is described in this work. These asynchronous tasks arise from the Uintah framework, which was developed to provide an environment for solving a broad class of fluid-structure interaction problems on structured adaptive grids. Uintah has a clear separation between its MPI-free user-coded tasks and its runtime system that ensures these tasks execute efficiently. This separation also allows for complete isolation of the application developer from the complexities involved with the parallelism Uintah provides. While we have designed scalable runtime systems for large CPU core counts, the emergence of heterogeneous systems, with additional on-node accelerators and co-processors presents additional design challenges in terms of effectively utilizing all computational resources on-node and managing multiple levels of parallelism. Our work addresses these challenges for Uintah by the development of new hybrid runtime system and Unified multi-threaded MPI task scheduler, enabling Uintah to fully exploit current and emerging architectures with support for asynchronous, out-of-order scheduling of both CPU and GPU computational tasks. This design coupled with an approach that uses MPI to communicate between nodes, a shared memory model on-node and the use of novel lock-free data structures, has made it possible for Uintah to achieve excellent scalability for challenging fluid-structure problems using mesh refinement on as many as 256K cores on the DoE Jaguar XK6 system. This design has also demonstrated an ability to run capability jobs on the heterogeneous systems, Keeneland and TitanDev. In this extended abstract, the evolution of Uintah and its runtime system is examined in the context of our new Unified multi-threaded scheduler design. The capabilities and performance of the Unified scheduler are also tested against previous Uintah scheduler and runtime designs. The final paper will then show more extensive results over a range in scales of processor core numbers on the DoE Jaguar XK6 system and with GPUs on the NSF Keeneland Initial Delivery System.
November 24, 2012 by hgpu
