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Efficient Scratchpad Allocation Algorithms for Energy Constrained Embedded Systems

  • Manish Verma
  • Lars Wehmeyer
  • Peter Marwedel
Part of the Lecture Notes in Computer Science book series (LNCS, volume 3164)

Abstract

In the context of portable embedded systems, reducing energy is one of the prime objectives. Memories are responsible for a significant percentage of a system’s aggregate energy consumption. Consequently, novel memories as well as novel memory hierarchies are being designed to reduce the energy consumption. Caches and scratchpads are two contrasting variants of memory architectures. The former relies completely on hardware logic while the latter requires software for its utilization. Most high-end embedded microprocessors today include onchip instruction and data caches along with a scratchpad.

Previous software approaches for utilizing scratchpad did not consider caches and hence fail for the prevalent high-end system architectures. In this work, we use the scratchpad for storing instructions. We solve the allocation problem using a greedy heuristic and also solve it optimally using an ILP formulation. We report an average reduction of 20.7% in instruction memory energy consumption compared to a previously published technique. Larger reductions are also reported when the problem is solved optimally.

The scratchpad in the presented architecture is similar to a preloaded loop cache. Comparing the energy consumption of our approach against that of preloaded loop caches, we report average energy savings of 28.9% using the heuristic.

Keywords

Memory architectures Memory allocation Energy aware compilation Integer Linear Programming Memory energy modeling 

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Copyright information

© Springer-Verlag Berlin Heidelberg 2005

Authors and Affiliations

  • Manish Verma
    • 1
  • Lars Wehmeyer
    • 1
  • Peter Marwedel
    • 1
  1. 1.Department of Computer Science XIIUniversity of DortmundDortmundGermany

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