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Matt Bishop Office: 2209 Watershed Sciences Phone: +1 (530) 752-8060 Email: mabishop@ucdavis.edu |
Version of April 7, 2022 at 10:21PM
| Multilevel Feedback Queue Scheduler Example | |||||
| Parameters: | |||||
| • quantum = 1 | |||||
| • Processes in q0 get 2 times at the CPU | |||||
| • Processes in q1 get 4 times at the CPU | |||||
| • Processes in q2 get as many times as they need at the CPU | |||||
| • J(U,T): job J with U units remaining on process and T time units remaining in queue | |||||
| time | run | q0 | q1 | q2 | |
| 0 | A(10,2) | ||||
| 1 | A(9, 1) | B(29,2) | |||
| 2 | B(28,1) | C(3,2) A(9,1) | |||
| 3 | C(2,1) | A(9,1) D(7,2) B(28,1) | |||
| 4 | A(8,0) | D(7,2) B(28,1) E(12,2) C(2,1) | |||
| 5 | D(6,1) | B(28,1) E(12,2) C(2,1) | A(8,4) | ||
| 6 | B(27,0) | E(12,2) C(2,1) D(6,1) | A(8,4) | ||
| 7 | E(11,1) | C(2,1) D(6,1) | A(8, 4) B(27,4) | ||
| 8 | C(1,0) | D(6,1) E(11,1) | A(8, 4) B(27,4) | ||
| 9 | D(5,0) | E(11,1) | A(8, 4) B(27,4) C(1,4) | ||
| 10 | E(10,0) | A(8, 4) B(27,4) C(1,4) D(5,4) | |||
| 11 | A(7,3) | B(27,4) C(1,4) D(5,4) E(10,4) | |||
| 12 | B(26,3) | C(1,4) D(5,4) E(10,4) A(7,3) | |||
| 13 | C(0, 3) | D(5,4) E(10,4) A(7,3) B(26,3) | |||
| *** C completes; T = 13-2 = 11; | |||||
| 14 | D(4,3) | E(10,4) A(7,3) B(26,3) | |||
| 15 | E(9,3) | A(7,3) B(26,3) D(4,3) | |||
| 16 | A(6,2) | B(26,3) D(4,3) E(9,3) | |||
| 17 | B(25,2) | D(4,3) E(9,3) A(6,2) | |||
| 18 | D(3,2) | E(9,3) A(6,2) B(25,2) | |||
| 19 | E(8,2) | A(6,2) B(25,2) D(3,2) | |||
| 20 | A(5,1) | B(25,2) D(3,2) E(8,2) | |||
| 21 | B(24,1) | D(3,2) E(8,2) A(5,1) | |||
| 22 | D(2,1) | E(8,2) A(5,1) B(24,1) | |||
| 23 | E(7,1) | A(5,1) B(24,1) D(2,1) | |||
| 24 | A(4,0) | B(24,1) D(2,1), E(7,1) | |||
| 25 | B(23,0) | D(2,1) E(7,1) | A(4) | ||
| 26 | D(1,0) | E(7,1) | A(4 B(23) | ||
| 27 | E(6,0) | A(4) B(23) D(1) | |||
| 28 | A(3) | B(23) D(1) E(6) | |||
| 29 | B(22) | D(1) E(6) A(3) | |||
| 30 | D(0) | E(6) A(3) B(22) | |||
| *** D completes: T = 30-3 = 27; W = 27-7 = 20; R = 27/7 = 3.9 | |||||
| 31 | E(5) | A(3) B(22) | |||
| 32 | A(2) | B(22) E(5) | |||
| 33 | B(21) | E(5), A(2) | |||
| 34 | E(4) | A(2) B(21) | |||
| 35 | A(1) | B(21) E(4) | |||
| 36 | B(20) | E(4) A(1) | |||
| 37 | E(3) | A(1) B(20) | |||
| 38 | A(0) | B(20) E(3) | |||
| *** A completes: T = 38-0 = 38; W = 38-10 = 28; R = 38/10 = 3.8 | |||||
| 39 | B(19) | E(3) | |||
| 40 | E(2) | B(19) | |||
| 41 | B(18) | E(2) | |||
| 42 | E(1) | B(18) | |||
| 43 | B(17) | E(1) | |||
| 44 | E(0) | B(17) | |||
| *** E completes: T = 44-4 = 40; W = 40-12 = 28; R = 40/12 = 3.3 | |||||
| 45 | B(16) | ||||
| 46 | B(15) | ||||
| 47 | B(14) | ||||
| 48 | B(13) | ||||
| 49 | B(12) | ||||
| 50 | B(11) | ||||
| 51 | B(10) | ||||
| 52 | B(9) | ||||
| 53 | B(8) | ||||
| 54 | B(7) | ||||
| 55 | B(6) | ||||
| 56 | B(5) | ||||
| 57 | B(4) | ||||
| 58 | B(3) | ||||
| 59 | B(2) | ||||
| 60 | B(1) | ||||
| 61 | B(0) | ||||
| *** B completes: T = 61-1 = 60; W = 60-29 = 31; R = 60/29 = 2.1 | |||||
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ECS 150, Operating Systems Version of April 7, 2022 at 10:21PM
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