Scheduling tasks with precedence relationsModifying the task parameters for RMSModifying ready times for RMS: exampleModifying the Ready times for RMSModified Ready times for RMSAssigning task priorities for RMSModifying task parameters for DMSModifying the Deadlines for DMSModifying task parameters for EDFModifying the Ready times for EDFSlide 11Modifying the Deadlines for EDFSlide 13CprE 458/558: Real-Time Systems (G. Manimaran) 1Scheduling tasks with precedence relationsScheduler{T1, T2}Conventional task setT1 T2Modify task parameters in order to respect precedence constraintsSchedulertask set with precedence constraintsCprE 458/558: Real-Time Systems (G. Manimaran) 2Modifying the task parameters for RMS•While using the RMS scheduler the task parameters (ready time) need to be modified in order to respect the precedence constraints•Rj* ≥ Max (Rj, Ri*) where Ri* is the modified ready time of the task Ti•Priority Prioi ≥ PriojTi TjCprE 458/558: Real-Time Systems (G. Manimaran) 3Modifying ready times for RMS: exampleT11T22T32T41T53Task RiCiDiT1 0 1 5T2 5 2 7T3 0 2 5T4 0 1 10T5 0 3 12Initial Task ParametersCprE 458/558: Real-Time Systems (G. Manimaran) 4Modifying the Ready times for RMST11T22T32T41T53Task RiCiDiT1 0 1 5T2 5 2 7T3 0 2 5T4 0 1 10T5 0 3 12Initial Task ParametersR1 = 0 R2 = 5R3 = 0R4 = 0R5 = 0R3’ = max(R1, R3)R3’ = 0R4’ = max(R1, R2,R4)R4’ = 5R5’ = max(R3’, R4’,R5)R5’ = 5CprE 458/558: Real-Time Systems (G. Manimaran) 5Modified Ready times for RMST11T22T32T41T53Task RiCiDiT1 0 1 5T2 5 2 7T3 0 2 5T4 5 1 10T5 5 3 12Modified Task ParametersR1 = 0 R2 = 5R3’ = 0R4’ = 5R5’ = 5CprE 458/558: Real-Time Systems (G. Manimaran) 6Assigning task priorities for RMST11T22T32T41T53Task RiCiDiT1 0 1 5T2 5 2 7T3 0 2 5T4 5 1 10T5 5 3 12Modified Task ParametersR1 = 0 R2 = 5R3’ = 0R4’ = 5R5’ = 5Assume all tasks of a connected component have the same period. Therefore, as per RMS all tasks will have a tie. We assign priorities to break the ties.Priority34210CprE 458/558: Real-Time Systems (G. Manimaran) 7Modifying task parameters for DMS•While using the DMS scheduler the task parameters (ready time, relative deadline) need to be modified in order to respect the precedence constraints•Rj* ≥ Max (Rj, Ri*)•Dj* ≥ Max (Dj, Di*) •Prioi ≥ PriojTi TjCprE 458/558: Real-Time Systems (G. Manimaran) 8Modifying the Deadlines for DMST11T22T32T41T53D1 = 5 D2 = 7D3 = 5D4 = 10D5 = 12D3’ = max(D1, D3)D3’ = 5D4’ = max(D1, D2,D4)D4’ = 10R5’ = max(D3’, D4’,D5)D5’ = 12Task RiCiDiT1 0 1 5T2 5 2 7T3 0 2 5T4 5 1 10T5 5 3 12Modified Task ParametersThe procedure to modify the ready times is same as that of RMSCprE 458/558: Real-Time Systems (G. Manimaran) 9Modifying task parameters for EDF•While using the EDF scheduler the task parameters need to be modified in order to respect the precedence constraints•Rj* ≥ Max (Rj, (Ri* + Ci))•Di* ≥ Min (Di, (Dj* – Cj)) Ti TjCprE 458/558: Real-Time Systems (G. Manimaran) 10Modifying the Ready times for EDFT11T22T32T41T53Task RiCiDiT1 0 1 5T2 5 2 7T3 0 2 5T4 0 1 10T5 0 3 12Initial Task ParametersR1 = 0 R2 = 5R3 = 0R4 = 0R5 = 0R3’ = max(R1 + C1, R3)R3’ = 1R4’ = max(R1+C1, R2+C2,R4)R4’ = 7R5’ = max(R3’+C3, R4’+C4,R5)R5’ = 8CprE 458/558: Real-Time Systems (G. Manimaran) 11Modifying the Ready times for EDFT11T22T32T41T53Task RiCiDiT1 0 1 5T2 5 2 7T3 1 2 5T4 7 1 10T5 8 3 12Modified Task ParametersR1 = 0 R2 = 5R3’ = 1R4’ = 7R5’ = 8CprE 458/558: Real-Time Systems (G. Manimaran) 12Modifying the Deadlines for EDFT11T22T32T41T53Task RiCiDiT1 0 1 5T2 5 2 7T3 1 2 5T4 7 1 10T5 8 3 12Modified Task ParametersD1 = 5 D2 = 7D3 = 5D4 = 10D5 = 12D3’ = Min( (D5 – C5), D3)D4’ = Min( (D5 – C5), D4)D3’ = 5D4’ = 9D2’ = Min( (D4’ – C4), D2)D2’ = Min( (D4’ – C4), (D3’ – C3), D1)D2’ = 7D1’ = 3CprE 458/558: Real-Time Systems (G. Manimaran) 13Modifying the Deadlines for EDFT11T22T32T41T53Task RiCiDiT1 0 1 3T2 5 2 7T3 1 2 5T4 7 1 9T5 8 3 12Modified Task ParametersD5 = 12D3’ = 5D4’ = 9D2’ = 7D1’ =