Dictionary sharing: An efficient cache compression scheme for compressed caches
Dictionary sharing: An efficient cache compression scheme for compressed caches
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字典共享：一种高效的压缩缓存压缩方案
DOI：
10.1109/micro.2016.7783704
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发表时间：
2016
期刊：
影响因子：
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通讯作者：
André Seznec
中科院分区：
文献类型：
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作者：
Biswabandan Panda;André Seznec
压缩缓存的有效性取决于三个功能：i）压缩方案，ii）压实方案，iii）压缩缓存的缓存布局。偏斜的压缩缓存（SCC）和另一个压缩缓存（YACC）是最近提出的两个压缩缓存布局，具有最小的存储空间和延迟开销，同时在更复杂的压缩缓存布局上实现了可比的性能。 SCC和YACC都使用压缩技术来压缩单个高速缓存块，然后使用压实技术将多个连续压缩块压缩到单个数据条目中。这些技术用于压实的主要属性是缓存块的压缩因子，在此过程中，它们浪费了缓存空间。在本文中，我们提出了词典共享（DIS），这是一种基于字典的缓存压缩方案，可减少浪费。 DISH通过记住该块是压实过程的潜在候选者，从而压缩了缓存块。 Dish用字典编码一个缓存块，该字典存储了缓存块的不同4字节块，并且字典在多个相邻的高速缓存块中共享。 DISH的简单编码方案还提供了单个循环减压延迟，并且不会更改压缩缓存的缓存布局。使用盘式的压缩缓存布局优于压缩方案，例如BDI和CPACK+Z，就压缩比（从1.7倍到2.3倍），系统性能（从7.2％到14.3％）和能源效率（从6个）（从6个） ％至16％）。
The effectiveness of a compressed cache depends on three features: i) the compression scheme, ii) the compaction scheme, and iii) the cache layout of the compressed cache. Skewed compressed cache (SCC) and yet another compressed cache (YACC) are two recently proposed compressed cache layouts that feature minimal storage and latency overheads, while achieving comparable performance over more complex compressed cache layouts. Both SCC and YACC use compression techniques to compress individual cache blocks, and then a compaction technique to compact multiple contiguous compressed blocks into a single data entry. The primary attribute used by these techniques for compaction is the compression factor of the cache blocks, and in this process, they waste cache space. In this paper, we propose dictionary sharing (DISH), a dictionary based cache compression scheme that reduces this wastage. DISH compresses a cache block by keeping in mind that the block is a potential candidate for the compaction process. DISH encodes a cache block with a dictionary that stores the distinct 4-byte chunks of a cache block and the dictionary is shared among multiple neighboring cache blocks. The simple encoding scheme of DISH also provides a single cycle decompression latency and it does not change the cache layout of compressed caches. Compressed cache layouts that use DISH outperforms the compression schemes, such as BDI and CPACK+Z, in terms of compression ratio (from 1.7X to 2.3X), system performance (from 7.2% to 14.3%), and energy efficiency (from 6% to 16%).