PORTAL: Power- and Thermal- Aware Computing


Motivation        Our Approach         People        Publications        Software


In sustainable computing, designers of computer systems, ranging from small mobile devices to massive data centers, emphasize obtaining a sustainable level of environmental and societal costs as the first-order design principle. These cost may result from the computer systems manufacturing, operation, and disposal. Among all the factors in sustainable computing that contribute to system operational costs, power and thermal dissipation are fundamental in modern computer-controlled systems. To understand the relationship between power & thermal dissipation and software applications, hardware manufacturers have provided capabilities such as dynamic voltage and frequency scaling (DVFS) to permit a dynamic reduction in the power dissipation. However, these capabilities may often have a negative and (sometimes) unpredictable effect upon the runtime performance of the software system.  

Due to inherent physical uncertainties and environmental dynamics as well as the interconnection between power and thermal dissipation in a system, empirical measurement study is crucial for understanding the system behavior. For instance, precise power and temperature measurements are required to fully evaluate the effectiveness of power-saving or temperature-reducing software design. Given this fundamental gap in software design for sustainable computing, we propose the development of an experimental infrastructure POweR and Thermal Aware computing Laboratory – PORTAL that captures the challenges and complexities of power and thermal–aware analysis of modern computer systems, including software power behavior analysis on different platforms and thermal effects under real–time system constrains. In PORTAL, we will develop software profiling techniques to assist developers in better understanding and optimizing the power dissipation associated with source code, under different hardware configurations. We will also formally introduce the software applications′ real–time requirements into dynamic thermal management (DTM).


Our  Approach

In combining theoretical results and experimental properties of modern computer systems′ power dissipation and thermal effects, PORTAL is expected to enable a broad range of research activities in the investigators′ groups and in the broad research community. Uniquely offering the capability of finegrained instrumenting, measuring, controlling, and correlating power and thermal dissipation, PORTAL will enable diverse research topics in investigators′ group, which include but not limit to the following: (1) system software power estimation and optimization based on mathematically power models and fieldexperiments; (2) real-time guarantees under thermal constrains according to control theories.

The basis of power–aware design is accurate, verbose, and real-time power estimation. A better understanding of the power dissipation of a system will enable more energy saving opportunities . Despite years of research efforts on computer system power estimation, most existing approaches either do not expose sufficient information to end–users and software developers or lack the consideration of platform-dependent factors. With more detailed information on power dissipation of workload, software developers will be enabled to leverage the algorithms and implementations to fulfill performance and power dissipation requirements. Thus, there exists a gap between the software design and runtime software dissipation. To bridge the gap, our major objective is exposing more software power dissipation information to operating systems, end users, and developers to enable greater energy-efficient design.

The advent and ubiquity of hardware technology such as DVFS has enabled software system designers to address temperature constraints via DTM. Typical DTM techniques involve determining opportune intervals, with respect to system performance constraints, during which the system′s execution may be reduced or stalled. The intervals of reduced execution permit the system to dissipate heat to the environment. For real–time systems, DTM techniques must ensure that system temporal constraints are not violated. Most prior work on DTM for real–time systems has been developed under the assumption that operating environment is static. However, this assumption is unlikely to hold in many real–world scenarios. Thus, we propose to address this objective by developing a framework for thermal–aware control of hard–real–time systems which includes methodology, analysis, and tools required to design and implement real–time systems that behave predictably under unexpected thermal changes in the environment.  




            Dr. Nathan Fisher 

            Dr. Weisong Shi 


            Hui Chen (graduated, now at Amazon)

            Pradeep Hettiarachchi (graduated, now at GM)

            Youhuizi Li (graduated, now at Hangdiang University)

            Bing Luo

            Quan Zhang

            Corey Tessler