作者bjk (Up2u)
看板Grad-ProbAsk
標題Re: [理工] [OS]-rate monotonic
時間Tue Feb 7 19:59:03 2012
http://en.wikipedia.org/wiki/Rate-monotonic_scheduling
The rate monotonic priority assignment is optimal meaning that if any static
priority scheduling algorithm can meet all the deadlines, then the rate
monotonic algorithm can too. The deadline-monotonic scheduling algorithm is
also optimal with equal periods and deadlines, in fact in this case the
algorithms are identical; in addition, deadline monotonic scheduling is
optimal when deadlines are less than periods.[4]
even period time cpu time
p1 50 25
p2 80 35
rate monotonic不可排
EDF(earliest-deadline first)可以排
我好像有聽說rate monotonic不可排，那其他排班法則也都不可排
能否解是一下
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◆ From: 203.70.50.18
→ metalalive:這個是恐龍本 real-time system 那章用的例子 02/07 20:23
→ metalalive:這要實際trace一下才知道 (還是說有更好的判斷方式?) 02/07 20:28
我是想問說這個例子
rate monotonic不可排
EDF(earliest-deadline first)可以排
但是我聽說只要，rate monotonic不可排，那就沒有排班法則可以排了
※ 編輯: bjk 來自: 203.70.50.18 (02/07 20:54)
推 rayway30419:rate monotonic的條件是static EDF不是唷 02/07 20:58
→ bjk:3QQ 02/07 21:29
推 jim055006:我記得他有一個公式可以判斷 02/07 23:56
→ jim055006:2[(2^n^-1)-1]，n代process個數，要是cpu utilization 02/07 23:58
→ jim055006:小於等於那個式子，則rate monotonic可以排 02/07 23:59