請問一下d選項的“CPU must guarantee…”
cpu是怎麼保證atomically executed呢？
我知道計組也有談到互斥存取這部分
但不太了解是怎麼或是有什麼元件達到的
※ 引述《clonsey1314 (Clonsey)》之銘言：
: 題目:
: Which one(s) of the following statements adequately describe the test-and-se
t
: (A) It does not work in multiprocessor environment.
: (B) It can all be implemented in the user space, provided that the lock vari
ab
: (C) It does not waste any CPU cycles when a process cannot acquire a lock
: (D) The CPU must guarantee that the test-and-set instruction is an atomic op
er
: 答案: (B)(D)
: 請問
: A選項: 書上說在multiprocessor系統下用test-and-set效能差, 這個選項錯是因為"只
是
: B選項: 硬體的support, 不是要在kernel mode下才能運作嗎? 還是我觀念有誤?