[理工] [OS] 100清大資工 scheduling

看板Grad-ProbAsk作者worldxxi (林小弟)時間12年前 (2012/01/11 01:16)推噓2(2推 0噓 16→)

留言18則, 7人參與討論串1/1

Choose the correct answer. Consider the following preemptive priority scheduling algorithm based on dynamically changing priorities. Larger priority numbers imply higher priority. When a process is waiting for The CPU (in the ready queue, but not running), its priority changes at a rate α when it is running, its priority changes at a rate ß. AlI pracesses are given a priority 0 when they enter the ready queue. What is the algorithm that results from ß > α > 0? A. Non-preemptive SJF B. Preemptive SJF. C. FCFS D. Non-preemptive priority E. Multilevel feedback queue F. None of the above 我是這樣解讀的：剛進ready queue的時候priority是0，輪到執行的時候變成ß，被強取後變成α。我是選CD，可是找不到哪裡有答案，有誰知道嗎？疑惑有兩個： 1.題目一開始說 preemptive priority scheduling，可是又給出ß > α > 0，我覺得ß > α > 0不就表示他是Non-preemptive priority scheduling，有點矛盾。 2.priority到底是什麼情況下會變成α？好像沒機會的感覺。 -- ※ 發信站: 批踢踢實業坊(ptt.cc) ◆ From: 122.116.225.176

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