DMA在内存间数据拷贝中的应用及其性能分析

在嵌入式系统中,进行大批量的数据拷贝操作会占用很多CPU资源,降低了系统响应速度.直接存储器存取(DMA)是一种高效的I/O(输入输出)方式,具有传输速度快、CPU资源消耗低的特点.使用DMA方式进行数据传输可以占用较少的CPU资源,同时获得较快的系统的响应速度和数据拷贝速率.因此可以将DMA方式应用到需要许多数据拷贝的场合.本文分析了DMA的原理和嵌入式处理器中DMA控制器(DMAC)的特点,给出了DMA应用的一些实例和内存之间使用DMA方式进行数据拷贝的性能分析.

Application of DMA in Data Copying between Memorys and Its Performance Analysis

In Embedded system,coping large number of data will occupy much CPU resource and slow down the response speed of the system.Direct Memory Access (DMA) is an efficent way of I/O(input output),it has the characteristic of high transmission speed and low costing of CPU resources. Transferring data using DMA will occupy less CPU resource ,synchronously obtain higher response speed of the system and higher copying speed. So DMA can be used in the occasion that requires a lot of copy.This paper presents the principle of DMA and the characteristic of DMAC(DMA controller) in embedded system ,and gives out some application instances of DMA and performance analysis of copying between memorys using DMA.