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Title: Impact of Quad-core Cray XT4 System and Software Stack on Scientific Computation

Conference ·
OSTI ID:1024224

An upgrade from dual-core to quad-core AMD processor on the Cray XT system at the Oak Ridge National Laboratory (ORNL) Leadership Computing Facility (LCF) has resulted in significant changes in the hardware and software stack, including a deeper memory hierarchy, SIMD instructions and a multi-core aware MPI library. In this paper, we evaluate impact of a subset of these key changes on large-scale scientific applications. We will provide insights into application tuning and optimization process and report on how different strategies yield varying rates of successes and failures across different application domains. For instance, we demonstrate that the vectorization instructions (SSE) provide a performance boost of as much as 50% on fusion and combustion applications. Moreover, we reveal how the resource contentions could limit the achievable performance and provide insights into how application could exploit Petascale XT5 system's hierarchical parallelism.

Research Organization:
Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States). National Center for Computational Sciences (NCCS)
Sponsoring Organization:
USDOE Office of Science (SC)
DOE Contract Number:
DE-AC05-00OR22725
OSTI ID:
1024224
Resource Relation:
Conference: Euro-Par 2009, Delft, Netherlands, 20090825, 20090828
Country of Publication:
United States
Language:
English