Tracing JIT tries to synthesize graph of all distinct execution paths (in practice for some smallish value of “all” at a time), ie. there is no sliding window.

Tracing JIT tries to synthesize graph of all distinct execution paths (in practice for some smallish value of “all” at a time), ie. there is no sliding window. In comparison OoO CPUs try to execute as much as possible of instructions they see “at once” (this can mean in parallel or in other order than is encoded by the instruction stream). Doing this in hardware involves looking at some block of memory (eg. L1I Cache line or several of them) and doing what is essentially an more involved variant of peephole optimization pass.