Overview

It is difficult to overestimate the magnitude of the discontinuity that the high performance computing (HPC) community is about to experience because of the emergence of next generation of multi-core and heterogeneous processor designs. For at least two decades, HPC programmers have taken it for granted that each successive generation of microprocessors would, either immediately or after minor adjustments, make their old software run substantially faster. But three main factors are converging to bring this "free ride" to an end.

First, system builders have encountered intractable physical barriers - too much heat, too much power consumption, and too much leaking voltage - to further increases in clock speeds. Second, physical limits on the number and bandwidth of pins on a single chip means that the gap between processor performance and memory performance, which was already bad, will get increasingly worse. Finally, the design trade-offs being made to address the previous two factors will render commodity processors, absent any further augmentation, inadequate for the purposes of tera- and petascale systems for advanced applications.

This daunting combination of obstacles has forced the designers of new multi-core and hybrid systems, searching for more computing power, to explore architectures that software built on the old model are unable to effectively exploit without radical modification. Currently available Linear Algebra software packages rely on parallel implementations of the Basic Linear Algebra Subroutines (BLAS) to take advantage of multiple execution units. This solution is characterized by a fork-join model of parallel execution, which may result in suboptimal performance on current and future generations of multi-core processors since it introduces strict dependencies due to the presence of non parallelizable portions of code. The PLASMA project aims to overcome the shortcomings of this approach by introducing a pipelined model of parallel execution.


Dec 19 2014 Admin Login