现代计算机的性能主要由每周期所执行的指令数（IPC）来衡量，而现代计算机的体系结构依靠指令级并行来改善性能。
The performance of modern computer systems is measured in terms of the number of instructions per cycle ( IPC ) . Modern architectures rely on instruction-level parallelism to improve performance .
每周期指令数