Lossless data compression techniques can potentially free up more than 50% of the memory resources. However, previously proposed schemes suffer from high access costs.

The proposed main-memory compression scheme practically eliminates performance losses of previous schemes by exploiting a simple and yet effective compression scheme, a highly-efficient structure for locating a compressed block in memory, and a hierarchical memory layout that allows compressibility of blocks to vary with a low fragmentation overhead. We have evaluated an embodiment of the proposed scheme in detail using 14 integer and floating point applications from the SPEC2000 suite along with two server applications and we show that the scheme robustly frees up 30% of the memory resources, on average, with a negligible impact on the performance of only 0.2% on average.