A new priority queue structure is introduced, for which the amortized time to insert a new element isO(1) while that for the minimumextraction is O(logK). K is the average, taken over all the deleted elements x, of the number of elements that are inserted during the lifespan of x and are still in the heap when x is removed. Several applications of our structure are mentioned.

A Bernoulli schedule is random service discipline for a multi-class priority queueing system which operates as follows: If queue i(l :s i :s N) is not empty just after servicing a message in its queue, a message in queue i is served again with probability Pi, and the highest class message present in the system is served with probability 1-Pi, where 0 :s Pi :s 1. This paper presents an analysis ...

AbstmctA direct application of commonly used synchronization primitives such as semaphores, monitors, or the Ada rendezvous can lead to uncontrolled priority inversion, a situation in which a higher priority job is blocked by lower priority jobs for an indefinite period of time. In this paper, we investigate two protocols belonging to the class of priority inheritance protocols, called the basi...

Existing concurrent priority queues do not allow to update the priority of an element after its insertion. As a result, algorithms that need this functionality, such as Dijkstra’s single source shortest path algorithm, resort to cumbersome and inefficient workarounds. We report on a heap-based concurrent priority queue which allows to change the priority of an element after its insertion. We sh...

When a real-time system is realized on a shared-memory multiprocessor, priority-ordered spin locks are often required to reduce priority inversions. However, simple priority-ordered spin locks can cause uncontrolled priority inversions when they are used for nested spin locks. This paper points out the problem of uncontrolled priority inversions in the context of spin locks and proposes priorit...

Using priority inheritance protocols is an e ective approach to solve the problem of uncontrolled priority inversion, which is among the major sources of deadline violations in hard real-time systems. In this paper, some approaches to incorporate priority inheritance to the ITRON speci cation are discussed. As the result, we propose two speci cations of priority inheritance semaphore functions ...