A survey of dynamic power optimization techniques

One of the most important considerations for the current VLSI/SOC design is power, which can be classified into power analysis and optimization. In this survey, the main concepts of power optimization including the sources and policies are introduced. Among the various approaches, dynamic power management (DPM), which implies to change devices states when they are not working at the highest speed or at their full capacity, is the most efficient one. Our explanations accompanying the figures specify the abstract concepts of DPM. This paper briefly surveys both heuristic and stochastic policies and discusses their advantages and disadvantages

3E: Energy-Efficient Elastic Scheduling for Independent Tasks in Heterogeneous Computing Systems

Reducing energy consumption is a major design constraint for modern heterogeneous computing systems to minimize electricity cost, improve system reliability and protect environment. Conventional energy-efficient scheduling strategies developed on these systems do not sufficiently exploit the system elasticity and adaptability for maximum energy savings, and do not simultaneously take account of user expected finish time. In this paper, we develop a novel scheduling strategy named energy-efficient elastic (3E) scheduling for aperiodic, independent and non-real-time tasks with user expected finish times on DVFS-enabled heterogeneous computing systems. The 3E strategy adjusts processors’ supply voltages and frequencies according to the system workload, and makes trade-offs between energy consumption and user expected finish times. Compared with other energy-efficient strategies, 3E significantly improves the scheduling quality and effectively enhances the system elasticity

A Multi-objective Perspective for Operator Scheduling using Fine-grained DVS Architecture

The stringent power budget of fine grained power managed digital integrated circuits have driven chip designers to optimize power at the cost of area and delay, which were the traditional cost criteria for circuit optimization. The emerging scenario motivates us to revisit the classical operator scheduling problem under the availability of DVFS enabled functional units that can trade-off cycles with power. We study the design space defined due to this trade-off and present a branch-and-bound(B/B) algorithm to explore this state space and report the pareto-optimal front with respect to area and power. The scheduling also aims at maximum resource sharing and is able to attain sufficient area and power gains for complex benchmarks when timing constraints are relaxed by sufficient amount. Experimental results show that the algorithm that operates without any user constraint(area/power) is able to solve the problem for most available benchmarks, and the use of power budget or area budget constraints leads to significant performance gain.Comment: 18 pages, 6 figures, International journal of VLSI design & Communication Systems (VLSICS

Concepts for design of an energy management system incorporating dispersed storage and generation

New forms of generation based on renewable resources must be managed as part of existing power systems in order to be utilized with maximum effectiveness. Many of these generators are by their very nature dispersed or small, so that they will be connected to the distribution part of the power system. This situation poses new questions of control and protection, and the intermittent nature of some of the energy sources poses problems of scheduling and dispatch. Under the assumption that the general objectives of energy management will remain unchanged, the impact of dispersed storage and generation on some of the specific functions of power system control and its hardware are discussed

Voltage Set-up Problem on Embedded Systems with Multiple Voltages

Dynamic voltage scaling (DVS), arguably the most effective energy reduction technique, can be enabled by having multiple voltages physically implemented on the chip and allowing the operating system to decide which voltage to use at run-time. Indeed, this is predicted as the future low-power system by International Technology Roadmap for Semiconductors (ITRS). There still exist many important unsolved problems on how to reduce the system's dynamic and/or total power by DVS. One of such problems, which we refer to as the voltage set-up problem, is "how many levels and at which values should voltages be implemented for the system to achieve the maximum energy saving". It challenges whether DVS technique's full potential in energy saving can be reached on multiple-voltage systems. In this paper, (1) we derive analytical solutions for dual-voltage system. (2) For the general case that does not have analytic solutions, we develop efficient numerical methods that can take the overhead of voltage switch and leakage into account. (3) We demonstrate how to apply the proposed algorithms on system design. (4) Interestingly, the experimental results, on both real life DSP applications and random created applications, suggest that multiple-voltage DVS systems with only a couple levels of voltages, when set up properly, can be very close to DVS technique's full potential in energy saving. Parts of this report were published in IEEE Transactions on Very Large Scale Integration (VLSI) Systems, Vol. 13, No. 7, pp. 869-872, July 2005

Genetic approach to minimizing energy consumption of VLSI processors using multiple supply voltages

科研費報告書収録論文(課題番号:17300009/研究代表者:亀山充隆/システムインテグレーション理論に基づく高安全知能自動車用VLSIの最適設計