HRM: H-tree based reconfiguration mechanism in reconfigurable homogeneous PE array

In order to accommodate the variety of algorithms with different performance in specific application and improve power efficiency,reconfigurable architecture has become an effective methodology in academia and industry.However,existing architectures suffer from performance bottleneck due to slow updating of contexts and inadequate flexibility.This paper presents an H-tree based reconfiguration mechanism(HRM)with Huffman-coding-like and mask addressing method in a homogeneous processing element(PE)array,which supports both programmable and data-driven modes.The proposed HRM can transfer reconfiguration instructions/contexts to a particular PE or associated PEs simultaneously in one clock cycle in unicast,multicast and broadcast mode,and shut down the unnecessary PE/PEs according to the current configuration.To verify the correctness and efficiency,we implement it in RTL synthesis and FPGA prototype.Compared to prior works,the experiment results show that the HRM has improved the work frequency by an average of 23.4%,increased the updating speed by 2×,and reduced the area by 36.9%;HRM can also power off the unnecessary PEs which reduced 51%of dynamic power dissipation in certain application configuration.Furthermore,in the data-driven mode,the system frequency can reach 214 MHz,which is 1.68×higher compared with the programmable mode.     

Dynamic Reconfigurable Structure with Rate Distortion Optimization

基于率失真优化的动态可重构结构

蒋林¹，张雪婷²，山蕊²，谢晓燕³，刘新闯²，贺飞龙³

（1.西安科技大学 集成电路设计实验室，西安 710054；

2.西安邮电大学 电子工程学院，西安 710121；

3.西安邮电大学 计算机学院，西安 710121）

摘要：

高效视频编码（High Efficiency Video Coding，HEVC）中的率失真优化（The Rate Distortion Optimization，RDO）算法具有许多的迭代和大量的计算，为减少计算时间满足不同规模RDO算法快速切换的需求。提出一种RDO动态可重构结构。首先，通过H树型配置网络（H-tree Configurable Network，HCN）加载量化参数（Quantization Parameter，QP）和比特率值，并实时检测阵列的执行状态。当检测到RDO算法的重构请求时，下发相应的配置信息。这种硬件自适应的自重构实现方法提高了硬件的灵活性和利用率。实验结果表明：当配置网路的控制位宽度仅增加31.25％时，可控处理单元的数量增加了32倍，执行周期比同类型设计降低了50％。与其他RDO实现方法相比，在基于配置网络的可重配置阵列上实现的RDO算法的平均工作频率增加了12.5％，面积减少了56.4％。

关键词：动态可重构；速率失真优化；类似霍夫曼编码；上下文切换；视频处理