嵌入式Linux的片上存储动态优化

On-Chip Memory Dynamic Optimization for Embedded Linux

为了充分利用片上高速便签存储器(scratch-pad memory,SPM),提升嵌入式Linux系统性能并降低功耗,该文提出一种面向嵌入式Linux用户进程的SPM动态优化方案.利用虚存管理技术在Linux内核的内存模型中添加SPM页区,建立以SPM页区为基础的动态SPM页框分配机制,并实现页框分配的通用接口函数.在实现对用户程序(包括代码段、栈和BSS段)优化的基础上,提出自主设计的自动采样交换器(auto profile and pageswap,APPS)优化方案.该方案能在内核态自动分析用户进程热点并通过专用DMA将其搬运到SPM中,最终实现多进程用户程序的动态SPM优化.实验结果表明,基于该优化方案的系统性能得到显著提升.

An on-chip memory （scratch-pad memory, SPM） dynamic optimization approach （auto profile and page swap, APPS） for Linux user process is explored to improve system performance and reduce power consumption. The SPM page zone is added to the memory model of Linux kernel by a virtual memory system. The dynamic allocation mechanism for the SPM page frame is implemented based on the SPM page zone. The general interface function for the SPM page frame assignment is provided for other processes. Based on optimization for user program including code, stack and BSS segment, the APPS scheme is introduced. This method can automatically analyze the hot-spots of processes in kernel mode and transmit them to the SPM zone by a dedicated DMA channel. Therefore, the multi-process user program will be dynamically optimized. Experimental results show that the proposed approach can improve the system performance.