Title
Decoupled Fused Cache: Fusing a Decoupled LLC with a DRAM Cache.
Abstract
DRAM caches have shown excellent potential in capturing the spatial and temporal data locality of applications capitalizing on advances of 3D-stacking technology; however, they are still far from their ideal performance. Besides the unavoidable DRAM access to fetch the requested data, tag access is in the critical path, adding significant latency and energy costs. Existing approaches are not able to remove these overheads and in some cases limit DRAM cache design options. For instance, caching DRAM cache tags adds constant latency to every access; accessing the DRAM cache using the TLB calls for OS support and DRAM cachelines as large as a page; reusing the last-level cache (LLC) tags to access the DRAM cache limits LLC performance as it requires indexing the LLC using higher-order address bits. In this article, we introduce Decoupled Fused Cache, a DRAM cache design that alleviates the cost of tag accesses by fusing DRAM cache tags with the tags of the on-chip LLC without affecting LLC performance. In essence, the Decoupled Fused Cache relies in most cases on the LLC tag access to retrieve the required information for accessing the DRAM cache while avoiding additional overheads. Compared to current DRAM cache designs of the same cacheline size, Decoupled Fused Cache improves system performance by 6% on average and by 16% to 18% for large cacheline sizes. Finally, Decoupled Fused Cache reduces DRAM cache traffic by 18% and DRAM cache energy consumption by 7%.
Year
DOI
Venue
2019
10.1145/3293447
TACO
Keywords
Field
DocType
3D stacking, Caches, DRAM, memory, processor
Dram,Computer science,Reuse,Latency (engineering),Cache,Parallel computing,Search engine indexing,Critical path method,Translation lookaside buffer,Energy consumption,Embedded system
Journal
Volume
Issue
ISSN
15
4
1544-3566
Citations 
PageRank 
References 
1
0.35
20
Authors
4
Name
Order
Citations
PageRank
Evangelos Vasilakis182.48
Vassilis Papaefstathiou29713.71
Pedro Trancoso337743.79
Ioannis Sourdis445644.17