It is contextual. The things like system IPC where 1% would be huge are also typically not written in C, but in a mix of C and assembly. But writing at that le

It is contextual. The things like system IPC where 1% would be huge are also typically not written in C, but in a mix of C and assembly. But writing at that level of specificity for an entire system greatly increases creation and maintenance time costs. You may lose the opportunity to make future performance improvements as a result.