Consider 5 periodic tasks $\tau_1, \tau_2, \cdots, \tau_5$ share two resources $R_1$ and $R_2$, as shown in the following table. Each task $\tau_i$ has its arrival time $A_i$, computation time $C_i$, period $P_i$, deadline $D_i$ and a set of critical sections. Note that a critical section is represented by [$R_j$, $st$:$ft$] which indicates $R_j$ will be accessed from time $st$ to $ft$. Suppose that the tasks are scheduled by RM and PCP.
[taskset]
Task | $A_i$ | $C_i$ | $P_i = D_i$ | Critical Section(s) |
---|---|---|---|---|
$\tau_1$ | $4$ | $2$ | $12$ | None |
$\tau_2$ | $0$ | $6$ | $25$ | [$R_1$, 1:5] |
$\tau_3$ | $7$ | $3$ | $10$ | [$R_2$, 1:2] |
$\tau_4$ | $2$ | $6$ | $20$ | [$R_1$, 1:5][$R_2$, 3:4] |
$\tau_5$ | $5$ | $3$ | $18$ | [$R_2$, 1:2] |
[fig] image
[taskset]
direct | PI | ceiling | |||||||||||
blocking | blocking | blocking | |||||||||||
$\tau_1$ | $\tau_2$ | $\tau_3$ | $\tau_4$ | $\tau_1$ | $\tau_2$ | $\tau_3$ | $\tau_4$ | $\tau_1$ | $\tau_2$ | $\tau_3$ | $\tau_4$ | worst-case blocking time | |
$\tau_1$ | X | X | X | ||||||||||
$\tau_2$ | X | X | X | ||||||||||
$\tau_3$ | X | X | X | ||||||||||
$\tau_4$ | X | X | X |