将基准测试代码放入实用程序类/方法中是很有用的。StopWatch类不需要在错误时被丢弃或停止。最简单的为动作计时的代码是

public partial class With
{
    public static long Benchmark(Action action)
    {
        var stopwatch = Stopwatch.StartNew();
        action();
        stopwatch.Stop();
        return stopwatch.ElapsedMilliseconds;
    }
}

示例调用代码

public void Execute(Action action)
{
    var time = With.Benchmark(action);
    log.DebugFormat(“Did action in {0} ms.”, time);
}

下面是扩展方法的版本

public static class Extensions
{
    public static long Benchmark(this Action action)
    {
        return With.Benchmark(action);
    }
}

以及示例调用代码

public void Execute(Action action)
{
    var time = action.Benchmark()
    log.DebugFormat(“Did action in {0} ms.”, time);
}

因为我不太关心精度，所以我最终比较了它们。我正在捕获网络上的大量数据包，我想在我收到每个数据包时放置时间。下面是测试500万次迭代的代码

    int iterations = 5000000;

    // Test using datetime.now
    {
        var date = DateTime.UtcNow.AddHours(DateTime.UtcNow.Second);

        var now = DateTime.UtcNow;

        for (int i = 0; i < iterations; i++)
        {
            if (date == DateTime.Now)
                Console.WriteLine("it is!");
        }
        Console.WriteLine($"Done executing {iterations} iterations using datetime.now. It took {(DateTime.UtcNow - now).TotalSeconds} seconds");
    }

    // Test using datetime.utcnow
    {
        var date = DateTime.UtcNow.AddHours(DateTime.UtcNow.Second);

        var now = DateTime.UtcNow;

        for (int i = 0; i < iterations; i++)
        {
            if (date == DateTime.UtcNow)
                Console.WriteLine("it is!");
        }
        Console.WriteLine($"Done executing {iterations} iterations using datetime.utcnow. It took {(DateTime.UtcNow - now).TotalSeconds} seconds");
    }

    // Test using stopwatch
    {
        Stopwatch sw = new Stopwatch();
        sw.Start();

        var now = DateTime.UtcNow;

        for (int i = 0; i < iterations; i++)
        {
            if (sw.ElapsedTicks == DateTime.Now.Ticks)
                Console.WriteLine("it is!");
        }
        Console.WriteLine($"Done executing {iterations} iterations using stopwatch. It took {(DateTime.UtcNow - now).TotalSeconds} seconds");
    }

输出结果为:

Done executing 5000000 iterations using datetime.now. It took 0.8685502 seconds 
Done executing 5000000 iterations using datetime.utcnow. It took 0.1074324 seconds 
Done executing 5000000 iterations using stopwatch. It took 0.9625021 seconds

总之，DateTime。如果您不太关心精度，UtcNow是最快的。这也支持了这个问题的答案https://stackoverflow.com/a/6986472/637142。

秒表的功能会更好(精度更高)。我还建议下载一款流行的分析器(DotTrace和ANTS是我用得最多的…免费试用的DotTrace功能齐全，不像其他一些唠叨)。

这不够专业:

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

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

更可靠的说法是:

PerformWork();

int repeat = 1000;

Stopwatch sw = Stopwatch.StartNew();
for (int i = 0; i < repeat; i++)
{
   PerformWork();
}

sw.Stop();

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

在我的实际代码中，我将添加GC。收集调用以将托管堆更改为已知状态，并添加Sleep调用，以便在ETW配置文件中轻松分离不同的代码间隔。

不，不是。使用秒表(在系统诊断中)

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

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

秒表自动检查是否存在高精度计时器。

值得一提的是DateTime。Now通常比DateTime慢一些。UtcNow是因为需要在时区、夏令时等方面做一些工作。

DateTime。UtcNow的分辨率通常为15毫秒。请看John Chapman关于DateTime的博客文章。现在我们来做一个精确的总结。

有趣的琐事:秒表回落到DateTime。UtcNow如果你的硬件不支持高频计数器。你可以通过查看静态字段Stopwatch. ishighresolution来检查Stopwatch是否使用硬件来实现高精度。

使用System.Diagnostics.Stopwatch类。

Stopwatch sw = new Stopwatch();
sw.Start();

// Do some code.

sw.Stop();

// sw.ElapsedMilliseconds = the time your "do some code" took.