> on modern ultra fast single user systems I wonder?
The latency of a 'syscall' is on the order of a few hundred instructions. You're switching to a different privilege mode, with a different memory map, and where your data ultimately has to leave the chip to reach hardware.
The latency of a 'syscall' is on the order of a few hundred instructions. You're switching to a different privilege mode, with a different memory map, and where your data ultimately has to leave the chip to reach hardware.
It's absurdly important and it will never not be.