※ 引述《lovefo (lovefo)》之銘言： : Scheduling in real time system: Consider two processes,P1 and P2,both : starting at time 0,where,P1=45 and P2=60 are the periodic of processes P1 and : P2,respectively;t1=25 and t2=30 are the processing times of processes P1 and P2, : respectively. : a.Can these two processes be scheduled using rate-monotonic scheduling?If yes, : what's the total CPU utilization? If no,which process will miss the : deadline first? : b.Repeat the above question for the case of scheduluing these two processes : using earliest-deadline-first(EDF) scheduling. : 請問這種類型的排班要怎麼做阿??? : earliest-deadline-first 不懂... ※ 引述《lovefo (lovefo)》之銘言： : Scheduling in real time system: Consider two processes,P1 and P2,both : starting at time 0,where,P1=45 and P2=60 are the periodic of processes P1 and : P2,respectively;t1=25 and t2=30 are the processing times of processes P1 and P2, : respectively. : a.Can these two processes be scheduled using rate-monotonic scheduling?If yes, : what's the total CPU utilization? If no,which process will miss the : deadline first? : b.Repeat the above question for the case of scheduluing these two processes : using earliest-deadline-first(EDF) scheduling. : 請問這種類型的排班要怎麼做阿??? : earliest-deadline-first 不懂... a.短的period time優先權較高 P2還沒做完，但P1的period到(45<60)所以搶奪CPU執行 ↓ P2執行完TIME為80，超過60 ↓ ↓ P1 P2 P1 P2 -------------------------- 0 25 45 70 80 因為P2不能在deadline內完成，所以不能schedule b.dynamic priority，較短的deadline有較高的優先權 P1，P2的(period time，deadline)如下: P1:(0,45);(45,90) ;(90,135) ;(135,180);(180,225)....等 P2:(0,60);(60,120);(120,180);(180,240)....等 P1註(1) ↓ P2註(2) P1 P2 ↓ ↓ ↓ ↓ | | P1 P2 P1 P2 P1 P2 | |P1 continue... ------------------------------------------------------------------ 0 25 55 80 110 135 165 180 註(1):45的時候P1的period time到了，但90(P1 deadline)>60(P2 deadline)， 所以P2的優先權較高，繼續執行 註(2):60的時候P2的period time到了，但120(P2 deadline)>90(P1 deadline)， 所以P1的優先權較高，繼續執行 後面的類推.......... 由圖可看出能排班 畫的好亂 有錯請說QQ --

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