PERIODIC TASK SCHEDULING - Hard Real-Time Computing Systems: Predictable Scheduling Algorithms and Applications - page 115

C i D i T i

τ 1 2 4 6

τ 2 2 5 8

τ 3 3 7 9

Table 4.4 A task set with relative deadlines less than periods.

τ 1

τ 2

τ 3

0 2 4 6 8 10 12 14 16 18 20 22 24

Figure 4.20 Schedule produced by EDF for the task set shown in Table 4.4.

L g (0 ,L ) result

4 2 OK

5 4 OK

7 7 OK

10 9 OK

13 11 OK

16 16 OK

21 18 OK

22 20 OK

Table 4.5 Testing intervals for the processor demand criterion.

Hence, condition (4.29) has to be tested for any deadline less than 25, and the set
of checking points is given by

. Table 4.5 shows the
results of the test and Figure 4.20 illustrates the schedule produced by EDF for the
task set.

D = { 4 , 5 , 7 , 10 , 13 , 16 , 21 , 22 }