Real-time scheduling with resource sharing on heterogeneous multiprocessors

• Authors: Björn Andersson;Gurulingesh Raravi
• Venue: Real-Time Systems
• Year: 2014

Consider the problem of scheduling a task set 驴 of implicit-deadline sporadic tasks to meet all deadlines on a t-type heterogeneous multiprocessor platform where tasks may access multiple shared resources. The multiprocessor platform has m k processors of type-k, where k驴{1,2,驴,t}. The execution time of a task depends on the type of processor on which it executes. The set of shared resources is denoted by R. For each task 驴 i , there is a resource set R i ⊆R such that for each job of 驴 i , during one phase of its execution, the job requests to hold the resource set R i exclusively with the interpretation that (i) the job makes a single request to hold all the resources in the resource set R i and (ii) at all times, when a job of 驴 i holds R i , no other job holds any resource in R i . Each job of task 驴 i may request the resource set R i at most once during its execution. A job is allowed to migrate when it requests a resource set and when it releases the resource set but a job is not allowed to migrate at other times. Our goal is to design a scheduling algorithm for this problem and prove its performance.We propose an algorithm, LP-EE-vpr, which offers the guarantee that if an implicit-deadline sporadic task set is schedulable on a t-type heterogeneous multiprocessor platform by an optimal scheduling algorithm that allows a job to migrate only when it requests or releases a resource set, then our algorithm also meets the deadlines with the same restriction on job migration, if given processors $4 \times (1 + \operatorname{MAXP}\times \lceil \frac{\vert P\vert \times\operatorname{MAXP}}{\min \{m_{1}, m_{2}, \ldots, m_{t} \}} \rceil )$ times as fast. (Here $\operatorname{MAXP}$ and |P| are computed based on the resource sets that tasks request.) For the special case that each task requests at most one resource, the bound of LP-EE-vpr collapses to $4 \times (1 + \lceil \frac{\vert R\vert }{\min \{m_{1}, m_{2}, \ldots, m_{t} \}} \rceil )$ . To the best of our knowledge, LP-EE-vpr is the first algorithm with proven performance guarantee for real-time scheduling of sporadic tasks with resource sharing on t-type heterogeneous multiprocessors.