高性能LTE终端通信协议栈缓存机制

CACHE MECHANISM OF HIGH PERFORMANCE LTE TERMINAL COMMUNICATION PROTOCOL STACK

针对LTE终端通信协议栈的处理过程中Cache缓存方式效率差,提出一种可以提高处理速度降低延时的数据缓存方式。通过利用便签式存储器(Scratch-Pad Memory,SPM)和直接内存存取方式(Direct Memory Access,DMA)的性能优势,将协议栈处理的过程中需要与处理器频繁交互的数据缓存到SPM中,实现在SPM中完成数据的包头压缩/解压、加密/解密和重组等协议功能处理,并通过DMA方式实现SPM与主存之间的数据搬运,减少处理器对大块连续数据的搬运,提高处理效率。该方式避免了CPU在通过Cache缓存方式进行数据交互容易发生缓存不命中的问题,从而提高了协议栈的数据处理效率。经过理论分析及实验对比,结果表明,在LTE协议栈处理过程中,采用SPM与DMA结合的数据缓存机制,相比Cache缓存方式可以使整体性能至少提升12.65%。

Aiming at the inefficiency of the Cache buffering,in the processing of the LTE terminal communication protocol stack,this paper proposes a data buffering method which can improve the processing speed and reduce the delay.By using the performance advantages of SPM and DMA,the data which needed to exchange with the processor frequently in the process of protocol stack processing was cached in SPM.The protocol function processing such as packet head compression/decompression,encryption/decryption and reorganization were realized in SPM.The data transfer between SPM and main memory was realized by DMA,which could reduce the transfer of large continuous data and improve the processing efficiency.This method avoids the problem that CPU is prone to cache miss in data exchange through cache,and improves the data processing efficiency of protocol stack.After theoretical analysis and experimental comparison,the results show that in the process of LTE protocol stack,the data cache mechanism combined with SPM and DMA can improve the overall performance by at least 12.65%compared with the Cache mode.