Chapter 4 - DSpace at Waseda University
Chapter 4 - DSpace at Waseda University
Chapter 4 - DSpace at Waseda University
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<strong>Chapter</strong> 5<br />
5.6 Summary<br />
We analyzed l<strong>at</strong>ency of HRTimer by using KAS th<strong>at</strong> is not perfect solution for timer<br />
l<strong>at</strong>ency. There is not only one reason of l<strong>at</strong>ency in the kernel but also complex reasons of<br />
l<strong>at</strong>ency from the kernel such as the rel<strong>at</strong>ion between processes, dependency with hardware<br />
interrupt (hardirq) [10] [19] and software interrupt (softirq). Thus, there’re so many reason of<br />
l<strong>at</strong>ency it’s impossible to solve the problem by one perfect solution. After high resolution<br />
timer l<strong>at</strong>ency experiment and analyzing event log, the most common problem is the priority<br />
of softirq.<br />
KAS evalu<strong>at</strong>ed problem of HRTimer, currently it is not possible to analyze other problems.<br />
However, it proved by using KAS along with the analysis of kernel timer, which is one of the<br />
most important and difficult problem in kernel. If a developer and a system administr<strong>at</strong>or<br />
used the KAS th<strong>at</strong> it is possible to analyze timer problems quickly and efficiently.<br />
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