[理工] OS: CPU utilization和response time衝突

作者: clonsey1314 (Clonsey)   2017-04-14 22:38:04
Discuss how the following pairs of scheduling criteria conflict in certain
settings.
(a) CPU utilization and response time
官方解答說:
"CPU utilization is increased if the overheads associatedwith context switching isminimized. The context switching
overheads could be lowered by performing context switches infrequently. This
could, however, result in increasing the response time for processes."
我知道context switch減少,CPU utilization會上升;
但不懂為何context switch減少會導致response time變長?
context switch減少,resonse time不是也會減少嗎?
作者: kyuudonut (善良老百姓)   2017-04-14 22:49:00
"performing context switches infrequently"當然別人輪到的時間就久了
作者: krusnoopy (push)   2017-04-15 12:09:00
假設P1,P2,P3同時到,1ms跟2ms做一次context switching當然後者的utilization高,但response time長囉你可能以為是降低context swithing的時間吧但是題目假設context switching時間一樣,只討論頻率
作者: s89162504 (阿本)   2017-04-15 16:42:00
先搞清楚response time的定義
作者: ken52011219 (呱)   2017-04-16 10:57:00
K大必推
作者: clonsey1314 (Clonsey)   2017-04-16 16:22:00
謝謝大家的解釋!

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