Berkeley Lab Scientific Computing Seminar

Date:

Friday, April 27, 2007

Time:

1:00pm-2:00pm

Location:

Building 50B-4205

Seminar Speaker:

Shoaib Kamil
UC Berkeley and LBNL

Title:

Reconfigurable Hybrid Interconnection for Static and Dynamic Scientific Applications

Abstract:

As we enter the era of peta-scale computing, system architects must plan for machines with unprecedented numbers of processors. Although fully connected networks such as fat- tree configurations currently dominate HPC interconnect designs, such approaches are inadequate for ultra-scale concurrencies due to the super- linear growth of component costs. Traditional low-degree interconnect topologies, such as 3D tori, have reemerged as a competitive solution due to their lower cost; however, such networks seem poorly suited for the requirements of many scientific applications at extreme concurrencies.

To address these limitations, we propose HFAST, a hybrid switch architecture that uses circuit switches to dynamically reconfigure lower- degree interconnects to suit the topological requirements of a given scientific application. We develop an optimization strategy for HFAST mappings and demonstrate that efficiency gains can be attained across a broad range of static numerical computations. Additionally, we conduct an extensive analysis of the communication characteristics of a dynamic AMR calculation and show that the HFAST approach can achieve significant advantages, even when com- pared with traditional fat-tree configurations. Overall results indicate hybrid interconnects have excellent potential for future ultrascale supercomputers.

Sponsor of Seminar:

Lenny Oliker

Scientific Computing

Contact Esmond G. Ng EGNg@lbl.gov