الگوریتم مسیریابی اصلاح شده بر اساس ¼ صفحه برای معماری شبکه درون تراشه‌ای(NoC) چنبره 3D

ABSTRACT Modified quadrant-based routing algorithm for 3D Torus Network-on-Chip architecture

As the number of cores is increasing to meet the high performance requirement of the Multiprocessor System-on-Chip (SoC), the Network-on-Chip (NoC) offered a scalable and alternative method for communication in place of bus based system which had limitation of the bandwidth and more power consuming (Dally and Towles, 2004). However, as number of cores increases on the chip, three-dimensional (3D) Network-on-Chip provides an attractive option to reduce the long flat interconnect with the short vertical one with the advantage of high throughput, low latency and low power consumption. With the 3D integration many heterogeneous circuits can be stacked vertically and can be connected by using through-silicon-vias (TSVs) (Cilardo and Fusella, 2016). TSVs provide the communication links between different layers. Because of very short and fine links they provide low delay, low power and high bandwidth communication channel. The cost of designing TSV is high and also very complex process with poor yields and defects. Instead of using TSV for all inter layer nodes, which causes significant area overhead and cost, a combination of 2D and 3D router with few TSV can be utilised (Chen et al., 2015). The topology decides the physical architecture of the interconnection network. The most common topologies are mesh, torus, ring etc. for both 2D and 3D NoCs (Ansari et al., 2015a). 3D Mesh topology is shown in Fig. 1.

The performance of the 3D NoC can be significantly affected by the routing algorithm (Chen et al., 2015). Therefore, it is always challenging to design optimum routing algorithm for the given topology. Routing algorithms should be designed to give low latency and high throughput with no congestion and deadlock along with fault tolerant ability (Ansari et al., 2015b). Various routing algorithms were proposed for the 3D NoCs like Ebrahimi et al. (2014) given algorithm for 3-D mesh based NoCs to distribute the unicast and multicast traffic. Khan and Ansari (2011a) presented an efficient routing algorithm Quadrant-based XYZ DOR for 3D Asymmetric Torus. Khan and Ansari (2011b) presented a routing algorithm based on binary search tree (BST) for the topology based on modified binary tree.

The contribution of present work consists of proposing an algorithm for the 3D Asymmetric torus with reduced vertical links. A modified quadrant-based routing algorithm for 3D torus NoC architecture is based on first dividing the space into different quadrants and then adopting the path which gives least hops to connect to the destination node. Topology for the proposed algorithm is shown in Fig. 2.