SFWRENG 4AA4 Lecture Notes - Lecture 6: Priority Ceiling Protocol, Mathtype
11 Oct 2016
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Nested critical sections 1 e. g. 1) 1. Priority ceiling protocol 1 e. g. 2) 2 e. g. 3) pcp protocol 2. Sporadic tasks 2 e. g. 4) 2. Doesn"t give a shit about when they were released. There is a maximum priority tasks can be given. The state of the art when resolving resource-contention issues . Deadlock free for an arbitrary number of tasks with an arbitrary number of resources acted upon in an arbitrary way. S2: no locked resources, so free access, if resource is locked by other tasks, s2 needs to have priority of t2 higher than the pc (s2). S1 is (suspended: priority higher than pc(s2) e. g. 3) pcp protocol. * no task can have a higher priority ceiling, so it"s suspended. Suspended: active choice, of access prevention until algorithm allows it to. Blocked: as a result of waiting for a resource to be free. T1 = (6, 2), t2 = (12, 3), t3 = (18, 3)
