Skewed Compressed Caches
Skewed Compressed Caches
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DOI：
10.1109/micro.2014.41
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发表时间：
2014-12
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影响因子：
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通讯作者：
S. Sardashti;André Seznec;D. Wood
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文献类型：
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作者：
S. Sardashti;André Seznec;D. Wood
高速缓存压缩利用较小高速缓存的面积和功能来寻求较大高速缓存的优势。理想情况下，压缩缓存通过紧密压缩压缩块来增加有效容量，具有低标记和元数据开销，并允许快速查找。然而，先前的压缩高速缓存设计未能实现所有这些目标。在本文中，我们提出了偏斜压缩缓存（SCC），一个新的硬件压缩缓存，降低开销，提高性能。SCC跟踪超级块以减少标记开销，将块压缩成可变数量的子块以减少内部碎片，但保留直接的标记-数据映射以快速找到块并消除额外的元数据（即，没有向后指针）。扫视使用新的稀疏超级块标记和倾斜的关联映射，考虑到压缩的大小。在我们的实验中，SCC提供了平均8%（高达22%）的性能提升，平均6%（高达20%）的总能耗降低，实现了最新的去耦压缩缓存的优势[26]，面积开销降低了4倍，设计复杂性降低了4倍。
Cache compression seeks the benefits of a larger cache with the area and power of a smaller cache. Ideally, a compressed cache increases effective capacity by tightly compacting compressed blocks, has low tag and metadata overheads, and allows fast lookups. Previous compressed cache designs, however, fail to achieve all these goals. In this paper, we propose the Skewed Compressed Cache (SCC), a new hardware compressed cache that lowers overheads and increases performance. SCC tracks super blocks to reduce tag overhead, compacts blocks into a variable number of sub-blocks to reduce internal fragmentation, but retains a direct tag-data mapping to find blocks quickly and eliminate extra metadata (i.e., No backward pointers). Saccades this using novel sparse super-block tags and a skewed associative mapping that takes compressed size into account. In our experiments, SCC provides on average 8% (up to 22%) higher performance, and on average 6% (up to 20%) lower total energy, achieving the benefits of the recent Decoupled Compressed Cache [26] with a factor of 4 lower area overhead and lower design complexity.