Emerging nonvolatile memories (NVMs) are promising to replace DRAM as main memory. However, NVMs suffer from limited write endurance and high write energy. Encoding method reduces the bit flips of NVMs by exploiting additional tag bits to encode the data. The effect of the encoding method is limited by the capacity overhead of the tag bits. In this article, we propose to exploit the space saved by compression to store the tag bits of the encoding method. We observe that the saved space size of each compressed cache line varies, and different encoding methods have different tradeoffs between capacity overhead and effect. To fully exploit the space saved by compression for improving lifetime, we select the proper encoding method according to the saved space size. To improve the compression coverage and compression ratio, we select an efficient compression scheme from two compression algorithms and provide more space for data encoding. Still, some data patterns cannot be compressed by any compression technique. We use the Flip-N-Write with 3.1% capacity overhead to encode uncompressible cache lines. The experimental results show that our scheme reduces the bit flips by 32.5%, decreases the energy consumption by 22.6% and improves the lifetime by 69.9% with 3.5% capacity overhead.

中文翻译：

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一种延长非易失性存储器寿命的低开销编码方案

新兴的非易失性存储器 (NVM) 有望取代 DRAM 作为主存储器。然而，NVM 受到写入耐久性和高写入能量的限制。编码方法通过利用额外的标签位对数据进行编码来减少 NVM 的位翻转。编码方法的效果受到标签位容量开销的限制。在本文中，我们建议利用压缩节省的空间来存储编码方法的标签位。我们观察到每个压缩缓存行节省的空间大小各不相同，不同的编码方法在容量开销和效果之间有不同的权衡。为了充分利用压缩节省的空间以提高寿命，我们根据节省的空间大小选择合适的编码方法。为了提高压缩覆盖率和压缩率，我们从两种压缩算法中选择一种高效的压缩方案，为数据编码提供更多空间。尽管如此，某些数据模式无法通过任何压缩技术进行压缩。我们使用容量开销为 3.1% 的 Flip-N-Write 来编码不可压缩的缓存行。实验结果表明，我们的方案减少了 32.5% 的位翻转，降低了 22.6% 的能耗，并在 3.5% 的容量开销下提高了 69.9% 的寿命。