Run-time Phase Prediction for a Reconfigurable VLIW Processor

Qi Guo, Anderson Sartor, Anthony Brandon, Antonio C.S. Beck, Xuehai Zhou, Stephan Wong

Research output: Chapter in Book/Conference proceedings/Edited volumeConference contributionScientificpeer-review

6 Citations (Scopus)


It is well-known that different applications exhibit varying amounts of ILP. Execution of these applications on the same fixed-width VLIW processor will result (1) in wasted energy due to underutilized resources if the issue-width of the processor is larger than the inherent ILP; or alternatively, (2) in lower performance if the issue-width is smaller than the inherent ILP. Moreover, even within a single application distinct phases can be observed with varying ILP and therefore changing resource requirements.With this in mind, we designed the ρ-VEX processor, which is a VLIW processor that can change its issuewidth
at run-time. In this paper, we propose a novel scheme to dynamically (i.e., at run-time) optimize the resource utilization by predicting and matching the number of active data-paths for each application phase. The purpose is to achieve low energy consumption for applications with low ILP, and high performance for applications with high ILP, on a single VLIW processor design. We prototyped the ρ-VEX processor on an FPGA and obtained the dynamic traces of applications running on top of a Linux port. Our results show that it is possible in some cases to achieve the performance of an 8-issue core with 10% lower energy consumption, while in others we achieve the energy consumption
of a 2-issue core with close to 20% lower execution time.
Original languageEnglish
Title of host publicationProceedings of the 2016 Design, Automation and Test in Europe Conference and Exhibition, DATE 2016
EditorsJürgen Teich
Place of PublicationPiscataway, NJ
Number of pages6
ISBN (Electronic)978-3-9815370-7-9
ISBN (Print)978-3-9815370-6-2
Publication statusPublished - 2016
Event2016 Design, Automation and Test in Europe Conference and Exhibition, DATE 2016 - Dresden, Germany
Duration: 14 Mar 201618 Mar 2016


Conference2016 Design, Automation and Test in Europe Conference and Exhibition, DATE 2016
Abbreviated titleDATE 2016


  • Delays
  • VLIW
  • Switches
  • Detectors
  • Energy consumption
  • Resource management
  • Hardware

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