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linux進程優(yōu)先級分為兩類:
靜態(tài)優(yōu)先級: 存于task_struct->static_prio即nice,默認為0,一旦被指定除非renice手工修改,否則不會自行調(diào)整;其決定了進程時間片的大;
動態(tài)優(yōu)先級: task_struct->prio,由調(diào)度程序使用,其以nice值為基礎(chǔ),進行(-5,+5)浮動; 調(diào)度程序通過進程休眠時間(task_struct->sleep_avg)判斷其交互性,若大部分時間都在休眠則為IO消耗型,否則為CPU消耗型;
注:這是參照Robert Love所著的linux kernel整理的筆記
In linux , total 140 priorities are available. In which , 0 - 99 are real time priorities and 100 to 139 are regular priorities. So it means for user only 100 to 139 are available but user can change this to real time priorities by using this command
對此一直有幾個疑問
1 top命令顯示的pr = 靜態(tài)優(yōu)先級 + 動態(tài)優(yōu)先級么?
2 top命令顯示普通進程的pr為何都是小于100?
3 top和ps顯示的pri是采用相同方式計算的嗎? |
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