问题
Whats the changed over time on how Linux system calls were implemented on older (8086/88) Intel CPUS vs more modern CPU's.
回答1:
The biggest change is the sysenter/sysexit (Intel's creation) and syscall/sysret (AMD's version) instructions on newer x86 (and Intel 64/AMD64) processors. These speed up system calls drastically compared to the interrupt method used previously. This has to do with reducing the steps the processor must go through when invoking a system call, and you can read up on them in the Intel manuals.
来源：https://stackoverflow.com/questions/14681029/linux-system-calls