Power is receiving a mounting share of attention. Innovation, fueled by the information and internet age, poses new challenges for electronic systems across a spectrum of applications. Mobile devices continue to break new frontiers of functional integration. Phones are now your email, social networking interface, video and music player, gaming device, camera, GPS, and more – all rolled into one. Yet the smart phone must survive through the day, and hopefully longer, without having to recharge the battery. Data centers and cloud computing grapple with power and carbon footprints as they move and process incredible amounts of data back and forth, consuming electricity to the order of 1-2% of the total that the entire world consumes. Advances in fabrication technology have made it possible for processors and system-on-chips (SoCs) to boast of over three-billion transistors, also pushing the limits of power density, integrity and reliability.
To address these challenges, power related design decisions are now being made throughout the product development cycle. Yet it is the early decisions that primarily govern the power and energy profile of a product. It is not surprising that key choices include how the design is partitioned into hardware versus software, the design architecture, and even to determine how the software controls the hardware. Once the design architecture is locked in, the most power-efficient implementation may lose out to an alternative more power-efficient architecture, even if the alternative is implemented half as well.
If the impact on power reduces when you go down levels of design abstraction, then predicting power with accuracy is the challenge at the higher levels of abstraction. It is unreasonable to expect the power numbers from a mostly untimed transaction-level design model to closely match numbers from a post-implementation design representation. At the same time, early power numbers must offer sufficient accuracy to evaluate design trade-offs relevant to the design abstraction level.
Models to the rescue