Embedded Linux, Real-time Performance And Performance Test Methods

Linux is widely used in consumer electronic, industrial control and telecomfields for its open source, robustness and efficiency, abundant in applications etc.Taking these advantages, developers also try to make Linux a real time system,substituting the traditional expansive embedded realtime OS.This thesis aims to provide a router prototype with good QoS and lower kernellatencies based on lots of research on Linux kernel realtime extension. Aiming toreduce the latency caused by several kinds of kernel locks, this thesis brings up apriority inheritance mutex, substituting these locks, which prevents system frompriority inversion and achieves good performance. Furthermore, this thesis drawsanother conclusion that all ISRs, except the system timer ISR, can be managed bykernel threads which scheduled by the O(1) scheduler. Then the locks disabled IRQscan also be replaced by mutex, which further improves the kernel preemptible feature.Additionally, this thesis enhances Linux timer system and provides better resolutionthan tradition kernel's 10ms timer. Therefore, the kernel gets highly extended.Successfully porting 2.6 Linux kernel to a MPC8260 board provides theenvironment for further development. As a part of thesis, several kinds of kernellatencies and their benchmark methods are discussed in the end of this thesis. Finally,this thesis looks forwards to new real time kernel technologies and discusses thepossible improvement of this system.