3 ms·
The overhead you are talking about is scoreboard, mainly - clockless CPU cannot assume readiness of the results when issuing commands, and it needs scoreboard
by thesz 8y ago
The overhead you are talking about is scoreboard, mainly - clockless CPU cannot assume readiness of the results when issuing commands, and it needs scoreboard of what is ready to issue commands without conflicts.
But scoreboarding allows for most gains of out-of-order execution and is cheap.
- deepnotderp 8y agoYeah, but most CPUs today are OoO without using scoreboarding
- thesz 8y agoYou may have associative memory for speculation (most probably, you refer to it above), but you need to have scoreboard for operation to be issued without conflict and with operands ready.