Real-time systems and real-time schedulability determination method

摘要

PROBLEM TO BE SOLVED: To provide a scheduling possibility determining method usable even when a plurality of processors are required to be simultaneously assigned to one task.;SOLUTION: A possibility that a deadline error of a task k may occur is determined under the condition of Σ_i=1...NMi*Uk,i≤Lk. When the number of processors is M, the number of tasks is N, and the cycle of the task i (1≤i≤N), the number of processors in use, processing time and relative deadline are Ti, Mi, Ci, Di respectively, Lk=(M-Mk+1)-(M-2Mk+1)Ck/Dk in the case of Mk≤(M+1)/2; Lk=M-Mk+1 in the case of (M+1)/2Mk; Uk,i=Ci/Ti{1+(Ti-Di)/Dk}+Ci/Dk in the case of Mk≤(M+1)/2, Mi(M+1)/2 and Xk,i≤0; Uk,i=Ci/Ti{1+(Ti-Di)/Dk}+(Ci-Xk,i*Ti)/Dk in the case of Mk≤(M+1)/2, Mi(M+1)/2 and 0Xk,iCi/Ti; and Uk,i=Ci/Ti{1+(Ti-Di)/Dk} in the case of Mk≤(M+1)/2, Mi(M+1)/2 and Ci/Ti≤Xk,i.;COPYRIGHT: (C)2006,JPO&NCIPI