找关于倒装(inversion)的英语论文

发布网友发布时间：2022-11-06 13:36

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热心网友时间：2023-10-25 15:38

In scheling, priority inversion is the scenario where a low priority task holds a shared resource that is required by a high priority task. This causes the execution of the high priority task to be blocked until the low priority task has released the resource, effectively "inverting" the relative priorities of the two tasks. If some other medium priority task attempts to run in the interim, it will take precedence over both the low priority task and the high priority task.

In most cases, priority inversion can occur without causing immediate harm -- the delayed execution of the high priority task goes unnoticed, and eventually the low priority task releases the shared resource. However, there are also many situations in which priority inversion can cause serious problems. If the high priority task is left starved of the resources, it might lead to a system malfunction or the triggering of pre-defined corrective measures, such as a watch dog timer resetting the entire system. The trouble experienced by the Mars lander "Mars Pathfinder" ("External links", below) is a classic example of problems caused by priority inversion in realtime systems.

Priority inversion can also rece the perceived performance of the system. Low priority tasks usually have a low priority because it is not important for them to finish promptly (for example, they might be a batch job or another non-interactive activity). Similarly, a high priority task has a high priority because it is more likely to be subject to strict time constraints -- it may be providing data to an interactive user, or acting subject to realtime response guarantees. Because priority inversion results in the execution of the low priority task blocking the high priority task, it can lead to reced system responsiveness, or even the violation of response time guarantees