Chapter 4 - DSpace at Waseda University

Chapter 4
execution times, and whole latency time of each event.
4.1 Introduction
As mentioned above, embedded systems often used in daily life mostly. One of most
important factors in embedded systems is the characteristic of real-time. Real-time
characteristic is the most important measure that divides the general Linux kernel and the
embedded kernel. In other words, an embedded system has a strong real-time characteristic.
Automobile brake system can be a simple example of an embedded system. The automobile
brake system is one of real-time systems that must not allow the delay. If latency of the
automobile break system occurred that causes a traffic accident. Also, real-time must be
assured for home appliances used, such as microwaves and washing machines. Time is an
important factor for the navigation system of an airplane or a weapon system. As mentioned
above, most of embedded systems are created by concerning real-time characteristics as one
of important factors. From small and light devices to very large devices, most of embedded
systems have to guarantee the deadline and when delay occurs, there is high a possibility of
serious accident.
Therefore, there is a need for a tool to analyze a latency problem of timers [33] and other
problems occurring in the kernel. An excellent kernel analysis tool is the most important for
problem solving and application development. There are a lot of kernel analysis tools in other
to analyze the Linux kernel. Some are provided as commerce products and some are provided
as open sources. Kernel analysis tools are essential to any kernels but most of kernel analysis
tools are not complete. Very basic analysis tools are partly provided by Linux and it is
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