3 ms·
MOV-to-CR3 is pretty slow, yes. In the ballpark of a hundred clock cycles, and you have to do 2 of them. The cost of a system call was about 1000 cycles, maybe
by bonzini 9y ago
MOV-to-CR3 is pretty slow, yes. In the ballpark of a hundred clock cycles, and you have to do 2 of them. The cost of a system call was about 1000 cycles, maybe less on newer processors---both OSes and processors optimize the hell out of SYSCALL/SYSRET.