Variability of process parameters in nanometer CMOS circuits makes standard worst-case design methodology waste much of the advantages ofscaling. A common-case design, though, is a perilous alternative, as it gives up much of the design yield. Better than worst-case (BTWC) design methodology reconciles performance and yield. In this paper we present a BTWC RISC processor that tolerates worst-case extra delays of critical paths without significant impact on the overall performance. We obtain this result by coupling latency-insensitive design and variable-latency (VL) units. A software built-in self-test checks VL units individually to determine whether to activate them or not. Compared to a worst-case approach, the RISC clock frequency increases by 23% in a 45nm CMOS technology. The impactof VL on instructions per cycle is circumscribed to the worst process case only and very limited, as we show through a set of benchmarks.

A synchronous latency-insensitive RISC for better than worst-case design / Casu, MARIO ROBERTO; Mantovani, P.. - In: INTEGRATION. - ISSN 0167-9260. - STAMPA. - 48:(2015), pp. 72-82. [10.1016/j.vlsi.2014.01.003]

A synchronous latency-insensitive RISC for better than worst-case design

CASU, MARIO ROBERTO;
2015

Abstract

Variability of process parameters in nanometer CMOS circuits makes standard worst-case design methodology waste much of the advantages ofscaling. A common-case design, though, is a perilous alternative, as it gives up much of the design yield. Better than worst-case (BTWC) design methodology reconciles performance and yield. In this paper we present a BTWC RISC processor that tolerates worst-case extra delays of critical paths without significant impact on the overall performance. We obtain this result by coupling latency-insensitive design and variable-latency (VL) units. A software built-in self-test checks VL units individually to determine whether to activate them or not. Compared to a worst-case approach, the RISC clock frequency increases by 23% in a 45nm CMOS technology. The impactof VL on instructions per cycle is circumscribed to the worst process case only and very limited, as we show through a set of benchmarks.
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Utilizza questo identificativo per citare o creare un link a questo documento: http://hdl.handle.net/11583/2572563
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