RISC-V is an open-source instruction set architecture (ISA) with a modular design consisting of a mandatory base part plus optional extensions. The RISC-V 32IMFC ISA configuration has been widely adopted for the design of new-generation, low-power processors. Motivated by the important energy savings that smaller-than-32-bit FP types have enabled in several application domains and related compute platforms, some recent studies have published encouraging early results for their adoption in RISC-V processors. In this paper we introduce a set of ISA extensions for RISC-V 32IMFC, supporting scalar and SIMD operations (fitting the 32-bit register size) for 8-bit and two 16-bit FP types. The proposed extensions are enabled by exposing the new FP types to the standard C/C++ type system and an implementation for the RISC-V GCC compiler is presented. As a further, novel contribution, we extensively characterize the performance and energy savings achievable with the proposed extensions. On average, experimental results show that their adoption provide benefits in terms of performance (1.64× speedup for 16-bit and 2.18× for 8-bit types) and energy consumption (30% saving for 16-bit and 50% for 8-bit types). We also illustrate an approach based on automatic precision tuning to make effective use of the new FP types.

Design and Evaluation of SmallFloat SIMD extensions to the RISC-V ISA / Tagliavini, G.; MacH, S.; Rossi, D.; Marongiu, A.; Benini, L.. - (2019), pp. 654-657. ((Intervento presentato al convegno 22nd Design, Automation and Test in Europe Conference and Exhibition, DATE 2019 tenutosi a Firenze Fiera, ita nel 2019 [10.23919/DATE.2019.8714897].

Design and Evaluation of SmallFloat SIMD extensions to the RISC-V ISA

Marongiu A.;
2019

Abstract

RISC-V is an open-source instruction set architecture (ISA) with a modular design consisting of a mandatory base part plus optional extensions. The RISC-V 32IMFC ISA configuration has been widely adopted for the design of new-generation, low-power processors. Motivated by the important energy savings that smaller-than-32-bit FP types have enabled in several application domains and related compute platforms, some recent studies have published encouraging early results for their adoption in RISC-V processors. In this paper we introduce a set of ISA extensions for RISC-V 32IMFC, supporting scalar and SIMD operations (fitting the 32-bit register size) for 8-bit and two 16-bit FP types. The proposed extensions are enabled by exposing the new FP types to the standard C/C++ type system and an implementation for the RISC-V GCC compiler is presented. As a further, novel contribution, we extensively characterize the performance and energy savings achievable with the proposed extensions. On average, experimental results show that their adoption provide benefits in terms of performance (1.64× speedup for 16-bit and 2.18× for 8-bit types) and energy consumption (30% saving for 16-bit and 50% for 8-bit types). We also illustrate an approach based on automatic precision tuning to make effective use of the new FP types.
22nd Design, Automation and Test in Europe Conference and Exhibition, DATE 2019
Firenze Fiera, ita
2019
654
657
Tagliavini, G.; MacH, S.; Rossi, D.; Marongiu, A.; Benini, L.
Design and Evaluation of SmallFloat SIMD extensions to the RISC-V ISA / Tagliavini, G.; MacH, S.; Rossi, D.; Marongiu, A.; Benini, L.. - (2019), pp. 654-657. ((Intervento presentato al convegno 22nd Design, Automation and Test in Europe Conference and Exhibition, DATE 2019 tenutosi a Firenze Fiera, ita nel 2019 [10.23919/DATE.2019.8714897].
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Utilizza questo identificativo per citare o creare un link a questo documento: http://hdl.handle.net/11380/1179005
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