Issue No. 07 - July (2008 vol. 57)
DOI Bookmark: http://doi.ieeecomputersociety.org/10.1109/TC.2008.28
As the speed of processors increases, the on-chip memory hierarchy will continue to be crucial for the performance. Unfortunately, simply increasing the size of the on-chip caches yields diminishing returns and memory-bound applications may suffer from the limited off-chip bandwidth. This paper focuses on memory-link compression schemes. A first contribution is a framework for identifying the nature of the value locality exploited by published schemes. This framework is then used to quantitatively establish what type of value locality is exploited by each compression scheme. We find that as many as 40% of the values transferred in integer, media, and commercial applications are small integers and can be coded using less than 8 bits. By leveraging small-value locality, 35% of the bandwidth can be freed up. Another significant chunk of the values either forms clusters in the value space or belongs to a fairly small group of frequent isolated values. By leveraging this category, one can free up 70% of the bandwidth. We finally contribute with a new compression scheme that exploits multiple value-locality categories and is shown to free up 75% of the bandwidth.
I/O and Data Communications, Data compaction and compression, Memory Structures
L. Spracklen, M. Thuresson and P. Stenstrom, "Memory-Link Compression Schemes: A Value Locality Perspective," in IEEE Transactions on Computers, vol. 57, no. , pp. 916-927, 2008.