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Resource access control -- example. T2 and T3 have access to a shared resource R. c i x : Task duration before entering the critical section c i y : Critical section duration c i z : Task duration after the critical section ci = c i x + c i y + c i z By RMS, T3 > T1 > T2. Schedules.
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Resource access control -- example T2 and T3 have access to a shared resource R cix : Task duration before entering the critical section ciy : Critical section duration ciz : Task duration after the critical section ci = cix + ciy + ciz By RMS, T3 > T1 > T2 CprE 458/558: Real-Time Systems (G. Manimaran)
Schedules Locks R Preempted by T3 RMS Schedule Direct blocking of T3 by T2 Release R T3 T1 T2 T3 T2 T1 T2 T3 T3 T2 10 11 12 0 2 4 6 7 8 14 16 Priority inversion of T3 by T1 RMS Schedule with Priority Inheritance Protocol Direct blocking of T3 by T2 T3 T1 T2 T3 T2 T3 T1 T3 T2 0 Inheritance blocking of T1 by T2 CprE 458/558: Real-Time Systems (G. Manimaran)