Browsing by Author "Wu, Ping-Ru"

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A High-Performance Double-Layer Counting Bloom Filter for Multicore Systems
(2015-11-01)
Lai, Bo-Cheng Charles
;
Chen, Kuan-Ting
;
Wu, Ping-Ru
;
電子工程學系及電子研究所
;
Department of Electronics Engineering and Institute of Electronics
The snoopy-based protocol is a widely used cache coherence mechanism for a symmetric multiprocessor (SMP) system. However, this broadcast-based protocol blindly disseminates data sharing information across the system, and introduces many unnecessary data operations. This paper proposes a novel architecture of double-layer counting Bloom filter (DLCBF) to reduce the unnecessary data lookups on the local cache and redundant data transactions on the shared interconnection of an SMP system. By adding an extra filtering layer, the DLCBF effectively exploits the data locality of applications. The two-layer hierarchy reduces the storage size of DLCBF by 18.75%, and achieves 81.99% and 31.36% better filtering rates when compared with a classic Bloom filter (BF) and original counting BF, respectively. When applied on the segmented shared bus of an SMP system, the DLCBF outperforms the previous work by 58% for In-filters and 1.86x for Out-filters. This paper also comprehensively explores the key design parameters of DLCBF, including the sizes of top-layer, bottom-layer, and multilayer design. The results show that enlarging the layer filters enhance the filtering rates of DLCBF, while adding an extra filter layer only provides slight benefit.
Reduce Data Coherence Cost with An Area Efficient Double Layer Counting Bloom Filter
(2012)
Chen, Kuan-Ting
;
Wu, Ping-Ru
;
Lai, Bo-Cheng Charles
;
電子工程學系及電子研究所
;
Department of Electronics Engineering and Institute of Electronics
The snoopy protocol is a widely used scheme to maintain cache coherence. However, the protocol requires a broadcast scheme and forces substantial unnecessary data searches at the local cache. This paper proposes a novel Double Layer Counting Bloom Filter (DLCBF) to significantly reduce the redundant data searches and transmission. The DLCBF implements an extra layer of hash function and the counting feature at each filter entry. By using the hierarchical structure of the hash function, DLCBF can effectively increase the successful filter rates while requiring a smaller memory usage than the conventional Bloom filters. Experimental results show that the DLCBF can screen out 4.05X of unnecessary cache searches and use 18.75% less memory compared to conventional Bloom filters. The DLCBF is also used to filter out the redundant data transmission on a hierarchical shared bus. Simulation results show that the DLCBF outperforms conventional filters by 58% for local transmissions and 1.86X for remote transmissions.