It's not a question of whether that .14 is negligible. His point is that it's literally meaningless.
Say you're benchmarking some routine. One particular measurement may be 300.14 ms. The next may be, say, 302.56 ms. The one after that, 297.12 ms. You have no way of knowing whether that .14 ms is due to the implementation of the routine, or whether it's simply noise in the measurement.
Say you're benchmarking some routine. One particular measurement may be 300.14 ms. The next may be, say, 302.56 ms. The one after that, 297.12 ms. You have no way of knowing whether that .14 ms is due to the implementation of the routine, or whether it's simply noise in the measurement.