A Method to find the Energy Optimal Speed Profiles of Multiple Interacting Devices

Sarma Vrudhula (Inventor)

Research output: Patent


The invention provides a method to find the globally energy optimum speed setting for an electronic system with multiple interacting devices. Examples of such systems include portable multimedia players, laptops, servers, wireless sensors, or even data centers. A software tool is provided that can be used by a system designer to mix and match modules that represent individual components of the system, and then compute the energy optimum speed profile for each component. The tool also provides a method to develop such modules for each system component, starting with the power and performance specifications of the component as input. Such modules can be developed by the system designer, or by the component manufacturer themselves (as they have better access to the device's internal data sheets/specifications). For example, a designer of a portable video player could use the tool to plug-in software modules that represent video decoder chips and DVD drives from different manufacturers. Then, the tool provides the energy optimal clock frequency/voltage setting for the decoder chip and the spindle motor speed setting for the DVD drive. Or, the manufacturer of the DVD drive could use this tool to develop the energy-speed characteristic module for the device by plugging into the tool measurement data on the drive's power and performance at different speeds.ApplicationsThe invention is useful for designers of energy-constrained systems who wish to find the global energy optimum speed setting for each of the multiple interacting components of their system. Examples of such systems/applications are: A laptop with a CD/DVD recorder: Recording an optical disk involves transferring data from the hard disk drive to the optical drive. The invention provides a means to compute the energy optimal speed setting for the hard drive and optical drive spindle motors. A portable system capable of multimedia playback from a disk drive: Multimedia playback involves reading encoded data from an optical drive (whose motor speed can be controlled) and decoding it using a video decoder (which is a digital integrated circuit whose supply voltage and frequency can be controlled). A portable device with a wireless network device that streams multimedia content to a processor: The network card's transmission rate/power can be controlled along with the processors voltage/frequency.A wide range of applications to the invention is possible, which are only limited by one's ability to abstract the system into multiple interacting modules whose speeds can be controlled. Further, the invention also provides a way to obtain the device characteristics for the individual speed-controllable components of the system. System designers or device manufacturers who have access to the component's electrical and performance specifications at various speeds can benefit from this.Advantages Currently, there exists no system-wide energy exploration tool that optimizes the speed settings for each controllable component of the system. The invention provides a means to achieve that. The particular approach used by this invention is unique in that it can perform this optimization in a way that is not specific to a given system or a component. This is made possible by the two-step approach. In the first step, each device is characterized independent of the system into which it is going to be placed. This makes it possible for the device characterization to be done by the device manufacturer themselves, who can then provide it as a software module to the system designer. In the second step, the system designer can plug in different modules so that they can choose between different candidate system combinations, thus being able to explore the design space in terms of energy efficiency.
Original languageEnglish (US)
StatePublished - Jun 27 2005


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