Title: Evaluating impact on CMPs' power for design inaccuracy diagnosis

Authors: Baisakhi Das; Biplab K. Sikdar

Addresses: Department of Information Technology, Guru Nanak Institute of Technology, Kolkata, India ' Department of Computer Science and Technology, Indian Institute of Engineering and Science and Technology, Shibpur, India

Abstract: In CMPs (Chip Multi-Processors), with thousand of processors, the issue of power dissipation has emerged as a matter of serious concern. Out of several factors responsible for huge power drainage the branch prediction unit of a processor contributes almost 10% of the overall power dissipation. This work aims to analyse the impact of inaccurate/faulty design on the branch predictors' power dissipation while realising speculative execution. The issue has been addressed through introduction of probable faults in a predictor that lead to mis-speculation. The prediction mechanism in CMPs also plays a role in dead-block identification, that is to avoid unutilised power consumption in a system as well as to overcome the poor cache efficiency. The performance loss of a system due to design inaccuracies/faults in dead-block prediction is also evaluated. The detail analysis reveals that the design inaccuracies of a predictor can cause a huge power loss, even up to 95%. The additional power loss in a processor can effectively be sensed to enable diagnosis of the faulty module (design inaccuracies) of predictor as well as to frame guidelines for operating mode of a CMP's cache system.

Keywords: CMPs; branch predictor; dead block prediction; speculative execution.

DOI: 10.1504/IJCAT.2017.088195

International Journal of Computer Applications in Technology, 2017 Vol.56 No.3, pp.198 - 209

Received: 25 May 2016
Accepted: 07 Dec 2016

Published online: 29 Nov 2017 *

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