Process variation and temperature aware adaptive scrubbing for retention failures in STT-MRAM
Process variation and temperature aware adaptive scrubbing for retention failures in STT-MRAM
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DOI：
10.1109/aspdac.2018.8297306
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发表时间：
2018-01
期刊：
影响因子：
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通讯作者：
Nour Sayed;S. Nair;R. Bishnoi;M. Tahoori
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文献类型：
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作者：
Nour Sayed;S. Nair;R. Bishnoi;M. Tahoori
自旋转移矩磁性随机存取存储器（STT-MRAM）是一种新兴的存储器技术，被认为是基于CMOS的片上存储器的有前途的替代品。它具有几个独特的优点，如非易失性，高耐久性，高密度，CMOS兼容性和可扩展性等。然而，由于工艺变化和温度效应导致的保留时间变化很大，因此保留失效已成为该技术的主要可靠性问题。减轻保留故障的常规解决方案是基于存储器阵列的最坏情况保留时间以规则间隔使用清理以防止错误的累积。但这会导致较大的性能和能源开销。在这项工作中，我们提出了一个过程的变化和温度感知擦洗技术，我们集群的该高速缓存线到不同的组的基础上，他们的保留时间，并使用不同的擦洗时间间隔为这些组。此外，基于操作温度在运行时调整清理间隔，以保证目标错误率要求。我们的研究结果表明，对于一个512 KB的缓存，组大小为4可以减少97%的性能和动态能量开销的擦洗，在相同的错误率约束。
Spin Transfer Torque Magnetic Random Access Memory (STT-MRAM) is an emerging memory technology, which is seen as a promising replacement for CMOS based on-chip memories. It has several distinctive advantages such as nonvolatility, high endurance, high density, CMOS compatibility and scalability among others. However, retention failure has emerged as a major reliability concern for this technology due to the large variations in retention time because of process variations and temperature effects. The conventional solution to mitigate retention failures is to use scrubbing at regular intervals to prevent accumulation of errors, based on the worst case retention time of the memory array. But this leads to large performance and energy overheads. In this work, we propose a process variation and temperature aware scrubbing technique, where we cluster the cache lines into different groups based on their retention times and use different scrubbing intervals for each of these groups. In addition, the scrubbing interval is adjusted at run-time based on the operating temperature, to guarantee target error rate requirements. Our results show that for a 512KB cache, a group size of 4 can reduce the performance and dynamic energy overheads of scrubbing by 97%, under the same error rate constraint.