Announcing version 6.0! New!

Version 6.0 introduces several new features that can be useful to special thermal modeling needs: 1) a upgraded solver based on SuperLU that significantly speeds up steady-state simulations; 2) an improved 3D model that supports layers with non-uniform thermal resistivity and heat capacity; 3) an improved secondary heat transfer path model that is compatible with 3D system. You can download version 6.0 here.

What is HotSpot?

HotSpot is an accurate and fast thermal model suitable for use in architectural studies. It is based on an equivalent circuit of thermal resistances and capacitances that correspond to microarchitecture blocks and essential aspects of the thermal package. The model has been validated using finite element simulation. HotSpot has a simple set of interfaces and hence can be integrated with most power-performance simulators like Wattch. The chief advantage of HotSpot is that it is compatible with the kinds of power/performance models used in the computer-architecture community, requiring no detailed design or synthesis description. HotSpot makes it possible to study thermal evolution over long periods of real, full-length applications.

Why thermal modeling?

With power density and hence cooling costs rising exponentially, temperature-aware design has become a necessity. Processor packaging is becoming a major expense, and for many chips can no longer be designed for the worst case. Furthermore, simple estimates of power dissipation are not a good proxy for direct measurement or simulation of temperature. There is an urgent need for design techniques to help control or reduce heat dissipation, especially runtime techniques that can regulate operating temperature when the package's capacity is exceeded. Runtime response provides safe cooling and prevents thermal emergencies by changing the processor's behavior rather than relying on costly thermal packaging. Evaluating such techniques, however, requires a thermal model that is practical for architectural studies, especially research or design-space investigations for which no detailed designs are yet available.