| 摘要 |
Schedulability determination method of determining whether real-time scheduling of tasks is possible using processors, includes calculating Lk and Sigma<SUB>i=1 . . . N</SUB>Mi*Uk,i, (1<=k,i<=N;k,i:integer) where Lk corresponds to task-k, Mi represents number of the one or more processors simultaneously used by task-i, Uk,i corresponds to task-k and task-i, and N represents number of tasks, and determining that real-time scheduling of tasks is possible using processors, if tasks all satisfy conditions, Sigma<SUB>i=1 . . . N</SUB>Mi*Uk,i<=Lk for all k (1<=k<=N), wherein Lk corresponds to task-k which is to be detected to satisfy corresponding one of conditions, Lk being expressed as follows <?in-line-formulae description="In-line Formulae" end="lead"?>if Mk<=(M+1)/2,<?in-line-formulae description="In-line Formulae" end="tail"?> <?in-line-formulae description="In-line Formulae" end="lead"?>Lk=(M-Mk+1)-(M-2Mk+1)Ck/Dk, and<?in-line-formulae description="In-line Formulae" end="tail"?> Uk,i is expressed as follows <?in-line-formulae description="In-line Formulae" end="lead"?>if Mk<=(M+1)/2, Mi<(M+1)/2, and Xk,i<=0, (1)<?in-line-formulae description="In-line Formulae" end="tail"?> <?in-line-formulae description="In-line Formulae" end="lead"?>Uk,i=Ci/Ti{1+(Ti-Di)/Dk}+Ci/Dk,<?in-line-formulae description="In-line Formulae" end="tail"?> <?in-line-formulae description="In-line Formulae" end="lead"?>if Mk<=(M+1)/2, Mi<(M+1)/2, and 0<Xk,i<CI/TI, (2)<?in-line-formulae description="In-line Formulae" end="tail"?> <?in-line-formulae description="In-line Formulae" end="lead"?>Uk,i=Ci/Ti{1+(Ti-Di)/Dk}+(Ci-Xk,i*Ti)/Dk, and<?in-line-formulae description="In-line Formulae" end="tail"?> <?in-line-formulae description="In-line Formulae" end="lead"?>if Mk<=(M+1)/2, Mi<(M+1)/2 and Ci/Ti<=XK,I, (3)<?in-line-formulae description="In-line Formulae" end="tail"?> <?in-line-formulae description="In-line Formulae" end="lead"?>Uk,i=Ci/Ti{1+(Ti-Di)/Dk},<?in-line-formulae description="In-line Formulae" end="tail"?> where M represents number of processors, Ti represents interval of task-i, Ci represents process time for processing task-i, Di represents relative deadline of task-i, and Xk,i=(Mk-Mi+(M-2Mk+1)Ck/Dk)/(M-2Mi+1).
|
