Study And Improvement On Real Time About Embedded Linux

With the developing of internet, EMPU(Embedded Micro Processor Unit) had been widely applied most of fields from Boeing to mobile.The high efficiency and stable of Linux kernel has been verified in most of fields. It is flexible for Linux kernle to cut out it and it is appropriate for embedded system.kernel. Its advantage is free, opening source, stable. Linux provides a strong supporter for developing applied software.But as a general operation system and Linux is not a really real time operation system, so it is only named soft real time and is not hard real time operation system. Its standard kernel has not supported event priority and preempted real time, at the same time, it has not provided predictable response time which has been needed for most of embedded application. So it is important to extend its real time performance during developing embedded Linux system.But there has three apparent shortcomings as a general operation system, i.e., long interrupted lock time, unpreempted kernel, fair schedule policy, so this paper will discuss next several parts to improve its real time performance in favor of developing the embedded system:Unpreempted kernel: this paper puts forward the modifying ideas from preempt lock, mutex lock, interrupt process and shedule function. Schedule algorithm: it set up a new shedule model and raises a new shedule algorithm from the cunent shedule bug.Interrupt processing and timer resolution: beacuse now Linux timer resolution is low, so this paper analyzed the advantage and shortcoming about the efficiency of timer interrupt, muti-shot timer interrupt and nice timer system.