DateTime.Now 是衡量函数性能的最佳方式吗? [英] Is DateTime.Now the best way to measure a function's performance?

问题描述

我需要找到瓶颈，需要尽可能准确地测量时间.

I need to find a bottleneck and need to accurately as possible measure time.

以下代码片段是衡量性能的最佳方式吗?

Is the following code snippet the best way to measure the performance?

DateTime startTime = DateTime.Now;

// Some execution process

DateTime endTime = DateTime.Now;
TimeSpan totalTimeTaken = endTime.Subtract(startTime);

推荐答案

不，不是.使用秒表(在System.Diagnostics)

Stopwatch sw = Stopwatch.StartNew();
PerformWork();
sw.Stop();

Console.WriteLine("Time taken: {0}ms", sw.Elapsed.TotalMilliseconds);

秒表会自动检查高精度计时器是否存在.

Stopwatch automatically checks for the existence of high-precision timers.

值得一提的是，DateTime.Now 通常比 DateTime.UtcNow 慢很多，因为必须使用时区来完成工作，夏令时 等.

It is worth mentioning that DateTime.Now often is quite a bit slower than DateTime.UtcNow due to the work that has to be done with timezones, DST and such.

DateTime.UtcNow 通常具有 15 毫秒的分辨率.请参阅John Chapman 的博文，了解DateTime.现在精确到一个很好的总结.

DateTime.UtcNow typically has a resolution of 15 ms. See John Chapman's blog post about DateTime.Now precision for a great summary.

有趣的小知识:如果您的硬件不支持高频计数器，秒表将返回 DateTime.UtcNow.您可以通过查看静态字段 秒表.IsHighResolution.

Interesting trivia: The stopwatch falls back on DateTime.UtcNow if your hardware doesn't support a high frequency counter. You can check to see if Stopwatch uses hardware to achieve high precision by looking at the static field Stopwatch.IsHighResolution.

这篇关于DateTime.Now 是衡量函数性能的最佳方式吗?的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！