An adaptive issue queue for reduced power at high performance


Alper Buyuktosunoglu, Stanley Schuster, David Brooks, Pradip Bose, Peter Cook, and David Albonesi. 6/11/2001. “An adaptive issue queue for reduced power at high performance.” Power-Aware Computer Systems, Pp. 25–39. Publisher's Version


Increasing power dissipation has become a major constraint for future performance gains in the design of microprocessors. In this paper, we present the circuit design of an issue queue for a superscalar processor that leverages transmission gate insertion to provide dynamic low-cost configurability of size and speed. A novel circuit structure dynamically gathers statistics of issue queue activity over intervals of instruction execution. These statistics are then used to change the size of an issue queue organization on-the-fly to improve issue queue energy and performance. When applied to a fixed, full-size issue queue structure, the result is up to a 70% reduction in energy dissipation. The complexity of the additional circuitry to achieve this result is almost negligible. Furthermore, self-timed techniques embedded in the adaptive scheme can provide a 56% decrease in cycle time of the CAM array read of the issue queue when we change the adaptive issue queue size from 32 entries (largest possible) to 8 entries (smallest possible in our design).

Last updated on 05/06/2022