Partitioning and Allocation of Scratch-Pad Memory for Energy Minimization of Priority-Based Preemptive Multi-Task Systems

Hideki TAKASE; Hiroyuki TOMIYAMA; Hiroaki TAKADA

doi:10.1587/transfun.E94.A.1954

Partitioning and Allocation of Scratch-Pad Memory for Energy Minimization of Priority-Based Preemptive Multi-Task Systems

Hideki TAKASE, Hiroyuki TOMIYAMA, Hiroaki TAKADA

Full Text Views

0

Share
Cite this

Summary :

Energy minimization has become one of the primary goals in the embedded real-time domains. Consequently, scratch-pad memory has been employed as partial or entire replacement for cache memory due to its better energy efficiency. However, most previous approaches were not applicable to a preemptive multi-task environment. We propose three methods of partitioning and allocation of scratch-pad memory for fixed-priority-based preemptive multi-task systems. The three methods, i.e., spatial, temporal, and hybrid methods, achieve energy reduction in the instruction memory subsystems. With the spatial method, each task occupies its exclusive space in scratch-pad memory. With the temporal method, the running task uses entire scratch-pad space. The content of scratch-pad memory is swapped out as a task executes or gets preempted. The hybrid method is based on the spatial one but a higher priority task can temporarily use the space of lower priority task. The amount of space is prioritized for higher priority tasks. We formulate each method as an integer programming problem that simultaneously determines (1) partitioning of scratch-pad memory space for the tasks, and (2) allocation of program code to scratch-pad memory space for each task. Our methods not only support the real-time task scheduling but also consider aggressively the periods and priorities of tasks for the energy minimization. Additionally, we implement an RTOS-hardware cooperative support mechanism for runtime code allocation to the scratch-pad memory space. We have made the experiments with the fully functional real-time operating system. The experimental results have demonstrated the effectiveness of our techniques. Up to 73% energy reduction compared to a conventional method was achieved.

Publication: IEICE TRANSACTIONS on Fundamentals Vol.E94-A No.10 pp.1954-1964

Publication Date: 2011/10/01

Publicized

Online ISSN: 1745-1337

DOI: 10.1587/transfun.E94.A.1954

Type of Manuscript: PAPER

Category: VLSI Design Technology and CAD

Cite this

Copy

Hideki TAKASE, Hiroyuki TOMIYAMA, Hiroaki TAKADA, "Partitioning and Allocation of Scratch-Pad Memory for Energy Minimization of Priority-Based Preemptive Multi-Task Systems" in IEICE TRANSACTIONS on Fundamentals, vol. E94-A, no. 10, pp. 1954-1964, October 2011, doi: 10.1587/transfun.E94.A.1954.
Abstract: Energy minimization has become one of the primary goals in the embedded real-time domains. Consequently, scratch-pad memory has been employed as partial or entire replacement for cache memory due to its better energy efficiency. However, most previous approaches were not applicable to a preemptive multi-task environment. We propose three methods of partitioning and allocation of scratch-pad memory for fixed-priority-based preemptive multi-task systems. The three methods, i.e., spatial, temporal, and hybrid methods, achieve energy reduction in the instruction memory subsystems. With the spatial method, each task occupies its exclusive space in scratch-pad memory. With the temporal method, the running task uses entire scratch-pad space. The content of scratch-pad memory is swapped out as a task executes or gets preempted. The hybrid method is based on the spatial one but a higher priority task can temporarily use the space of lower priority task. The amount of space is prioritized for higher priority tasks. We formulate each method as an integer programming problem that simultaneously determines (1) partitioning of scratch-pad memory space for the tasks, and (2) allocation of program code to scratch-pad memory space for each task. Our methods not only support the real-time task scheduling but also consider aggressively the periods and priorities of tasks for the energy minimization. Additionally, we implement an RTOS-hardware cooperative support mechanism for runtime code allocation to the scratch-pad memory space. We have made the experiments with the fully functional real-time operating system. The experimental results have demonstrated the effectiveness of our techniques. Up to 73% energy reduction compared to a conventional method was achieved.
URL: https://globals.ieice.org/en_transactions/fundamentals/10.1587/transfun.E94.A.1954/_p

Copy

@ARTICLE{e94-a_10_1954,
author={Hideki TAKASE, Hiroyuki TOMIYAMA, Hiroaki TAKADA, },
journal={IEICE TRANSACTIONS on Fundamentals},
title={Partitioning and Allocation of Scratch-Pad Memory for Energy Minimization of Priority-Based Preemptive Multi-Task Systems},
year={2011},
volume={E94-A},
number={10},
pages={1954-1964},
abstract={Energy minimization has become one of the primary goals in the embedded real-time domains. Consequently, scratch-pad memory has been employed as partial or entire replacement for cache memory due to its better energy efficiency. However, most previous approaches were not applicable to a preemptive multi-task environment. We propose three methods of partitioning and allocation of scratch-pad memory for fixed-priority-based preemptive multi-task systems. The three methods, i.e., spatial, temporal, and hybrid methods, achieve energy reduction in the instruction memory subsystems. With the spatial method, each task occupies its exclusive space in scratch-pad memory. With the temporal method, the running task uses entire scratch-pad space. The content of scratch-pad memory is swapped out as a task executes or gets preempted. The hybrid method is based on the spatial one but a higher priority task can temporarily use the space of lower priority task. The amount of space is prioritized for higher priority tasks. We formulate each method as an integer programming problem that simultaneously determines (1) partitioning of scratch-pad memory space for the tasks, and (2) allocation of program code to scratch-pad memory space for each task. Our methods not only support the real-time task scheduling but also consider aggressively the periods and priorities of tasks for the energy minimization. Additionally, we implement an RTOS-hardware cooperative support mechanism for runtime code allocation to the scratch-pad memory space. We have made the experiments with the fully functional real-time operating system. The experimental results have demonstrated the effectiveness of our techniques. Up to 73% energy reduction compared to a conventional method was achieved.},
keywords={},
doi={10.1587/transfun.E94.A.1954},
ISSN={1745-1337},
month={October},}

Copy

TY - JOUR
TI - Partitioning and Allocation of Scratch-Pad Memory for Energy Minimization of Priority-Based Preemptive Multi-Task Systems
T2 - IEICE TRANSACTIONS on Fundamentals
SP - 1954
EP - 1964
AU - Hideki TAKASE
AU - Hiroyuki TOMIYAMA
AU - Hiroaki TAKADA
PY - 2011
DO - 10.1587/transfun.E94.A.1954
JO - IEICE TRANSACTIONS on Fundamentals
SN - 1745-1337
VL - E94-A
IS - 10
JA - IEICE TRANSACTIONS on Fundamentals
Y1 - October 2011
AB - Energy minimization has become one of the primary goals in the embedded real-time domains. Consequently, scratch-pad memory has been employed as partial or entire replacement for cache memory due to its better energy efficiency. However, most previous approaches were not applicable to a preemptive multi-task environment. We propose three methods of partitioning and allocation of scratch-pad memory for fixed-priority-based preemptive multi-task systems. The three methods, i.e., spatial, temporal, and hybrid methods, achieve energy reduction in the instruction memory subsystems. With the spatial method, each task occupies its exclusive space in scratch-pad memory. With the temporal method, the running task uses entire scratch-pad space. The content of scratch-pad memory is swapped out as a task executes or gets preempted. The hybrid method is based on the spatial one but a higher priority task can temporarily use the space of lower priority task. The amount of space is prioritized for higher priority tasks. We formulate each method as an integer programming problem that simultaneously determines (1) partitioning of scratch-pad memory space for the tasks, and (2) allocation of program code to scratch-pad memory space for each task. Our methods not only support the real-time task scheduling but also consider aggressively the periods and priorities of tasks for the energy minimization. Additionally, we implement an RTOS-hardware cooperative support mechanism for runtime code allocation to the scratch-pad memory space. We have made the experiments with the fully functional real-time operating system. The experimental results have demonstrated the effectiveness of our techniques. Up to 73% energy reduction compared to a conventional method was achieved.
ER -