A Bypassing Mechanism for Application-Adaptive Cache Resizing

Masayuki SATO  Takumi TAKAI  Ryusuke EGAWA  Hiroyuki TAKIZAWA  Hiroaki KOBAYASHI  

D - Abstracts of IEICE TRANSACTIONS on Information and Systems (Japanese Edition)   Vol.J99-D   No.3   pp.337-347
Publication Date: 2016/03/01
Online ISSN: 1881-0225
Type of Manuscript: PAPER
cache bypassing,  dead-on-fill block,  dynamic cache resizing mechanism,  energy consumption,  

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Dynamic cache resizing mechanisms reduce the energy consumed by the caches by cutting off the power supply to some of cache regions on demands from executed applications. However, in the case where the caches are occupied by many dead-on-fill blocks, which are never accessed until their eviction, these blocks prevent the dynamic cache resizing mechanisms from disabling more cache regions, resulting in a limited energy reduction. Therefore, this paper proposes a cache bypassing mechanism for the dynamic cache resizing mechanisms to obtain further energy reduction. The proposed mechanism forces some of accssed data blocks bypass the last-level caches. The bypass rate is adjusted to be heigher if an application accesses more dead-on-fill blocks. As a result, the proposed mechanism reduces the number of dead-on-fill blocks in the cache and enables the dynamic cache resizing mechanisms to disable more cache regions. The evaluation results demonstrate that the proposed mechanism can reduce the energy consumption of the cache by up to 48%, and an average of 5%.