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 />
priority task occurs while a low priority task is running, the low priority task goes to the sleep<br />
mode and high priority task starts working. The preemptive kernel can run the low priority<br />
task after high priority task ends.<br />
5.2.2 Non-preemptive Kernel<br />
Non-preemptive section is very important in general-purpose OS and RTOS as priority is<br />
not allowed in non-preemptive section. RTOS is decided the performance by response time in<br />
non-preemptive section. Wh<strong>at</strong>ever there is a request of high priority task, it cannot be<br />
performed immedi<strong>at</strong>ely. There are some problems with response time. When the l<strong>at</strong>ency of a<br />
certain non-preemptive section is 10 seconds, the real-time task can be running after 10<br />
seconds. Therefore, problem of non-preemptive task is solved in general Linux by using<br />
locking of critical section.<br />
Figure 5.4 Process of interrupt of non-preemptive kernel
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