Sharif Digital Repository

Although phase change memory with multi-bit storage capability (known as MLC PCM) offers a good combination of high bit-density and non-volatility, its performance is severely impacted by the increased read/write latency. Regarding read operation, access latency increases almost linearly with respect to cell density (the number of bits stored in a cell). Since reads are latency critical, they can seriously impact system performance. This paper alleviates the problem of slow reads in the MLC PCM by exploiting a fundamental property of MLC devices: the Most-Significant Bit (MSB) of MLC cells can be read as fast as SLC cells, while reading the Least-Significant Bits (LSBs) is slower. We propose... 

Newly developed 3D die stacking technologies affords us the possibility to revisit the idea of Processing-in-Memory (PIM) as implementation hurdles are overcome. We now have the opportunity to offload the data intensive parts of our program to the PIM in form of kernels to be able to take advantage of the high internal bandwidth of the memory modules. Memory access latency and bandwidth are two major bottlenecks in today’s high-performance computers and new use-cases are moving faster than ever before towards this mode of computing. With new graph processing and neural network applications being developed every day, having a performance model of such systems helps in predicting the behavior... 

Graphics Processing Units (GPUs) employ large register files to accommodate all active threads and accelerate context switching. Unfortunately, register files are a scalability bottleneck for future GPUs due to long access latency, high power consumption, and large silicon area provisioning. Prior work proposes hierarchical register file to reduce the register file power consumption by caching registers in a smaller register file cache. Unfortunately, this approach does not improve register access latency due to the low hit rate in the register file cache. In this article, we propose the Latency-Tolerant Register File (LTRF) architecture to achieve low latency in a two-level hierarchical...