使用 Timer 查找性能瓶颈

Created: November-22, 2018

优化速度的第一步是找到最慢的代码段。Timer VBA 函数返回自午夜以来经过的秒数，在基于 Windows 的 PC 上精度为 1/256 秒（3.90625 毫秒）。VBA 函数 Now 和 Time 仅精确到秒。

Dim start As Double       ' Timer returns Single, but converting to Double to avoid 
start = Timer             ' scientific notation like 3.90625E-03 in the Immediate window
' ... part of the code
Debug.Print Timer - start; "seconds in part 1" 

start = Timer
' ... another part of the code
Debug.Print Timer - start; "seconds in part 2"