Patent Document ID: 20120284728
Application ID: 13395102
Patent Flag: 0

Claim One:
1. A method for the real-time dynamic priority scheduling of an application executed on at least one processor, said application consisting of a plurality m of software tasks executing at least one processing operation on a plurality of N successive data frames, each of said tasks i being defined at least, for each of said frames j, by an execution time C i j , an execution deadline D i j and a guard time P i j with respect to the next frame j+1, said guard time P i j being greater than or equal to said deadline D i j , said method comprising: for each task i, calculating the ratios C i j D i j between the execution time C i j of each frame j and the corresponding deadline D i j , for each task i, searching for the maximum of said ratios over all of said frames j max ( C i j D i j ) , comparing the sum ∑ i = 0 m - 1 max 0 ≤ j ≤ N - 1 ( C i j D i j ) over all of said tasks i of said maxima with the number p of processors operating in parallel over which the total computation load of said real-time application is distributed, if said sum ∑ i = 0 m - 1 max 0 ≤ j ≤ N - 1 ( C i j D i j ) is less than or equal to the number p of processors, then concluding on the feasibility of the real-time execution of all of said software tasks distributed over said processors and associating a dynamic execution priority with the task i according to its execution deadline D i j so that, at a given instant, the task which has the highest priority is the one whose deadline is the closest in time D i j , if said sum ∑ i = 0 m - 1 max 0 ≤ j ≤ N - 1 ( C i j D i j ) is strictly greater than the number p of processors, rejecting the task i and/or redefining its execution time C i j and execution deadline D i j parameters so as to satisfy the inequality ∑ i = 0 m - 1 max 0 ≤ j ≤ N - 1 ( C i j D i j ) ≤ p .