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C#中的Stopwatch如何使用

发布时间:2023-02-25 10:43:23 来源:亿速云 阅读:144 作者:iii 栏目:开发技术

本篇内容主要讲解“C#中的Stopwatch如何使用”,感兴趣的朋友不妨来看看。本文介绍的方法操作简单快捷,实用性强。下面就让小编来带大家学习“C#中的Stopwatch如何使用”吧!

    C# Stopwatch的使用

    什么是Stopwatch

    Stopwatch:提供一组方法和属性,可以准确的测量运行时间。

    使用的时候需要引用命名空间:System.Diagnostics。

    Stopwatch的简单使用

    //创建Stopwatch实例
    Stopwatch sw = new Stopwatch();
    //开始计时
    sw.Start();
    for (int i = 0; i < 100; i++)
    {
      Console.WriteLine(i);
    }
    //停止计时
    sw.Stop();
    Console.WriteLine("用时:" + sw.ElapsedMilliseconds + "");
    //重置 停止时间间隔测量,并将运行时间重置为0
    sw.Reset();
    Console.WriteLine("用时:" + sw.ElapsedMilliseconds + "");
    //重启 停止时间间隔测量,并将运行时间重置为0,然后重新开始测量运行时间
    sw.Restart();
    for (int i = 0; i < 100; i++)
    {
      Console.WriteLine(i);
    }
    sw.Stop();
    //获取当前实例测量得出的总运行时间(以毫秒为单位)
    Console.WriteLine("用时:" + sw.ElapsedMilliseconds + "");
    //获取当前实例测量得出的总运行时间
    Console.WriteLine("用时:"+sw.Elapsed); 
    //获取当前实例测量得出的总运行时间(用计时器刻度表示)。
    Console.WriteLine(sw.ElapsedTicks);
    Console.Read();
    //使用StartNew,相当于已经实例化并且启动计时
    Stopwatch sw=Stopwatch.StartNew();
    for (int i = 0; i < 100; i++)
    {
      Console.WriteLine(i);
    }
    sw.Stop();
    //获取当前实例测量得出的总运行时间(以毫秒为单位)
    Console.WriteLine("用时:" + sw.ElapsedMilliseconds + "");
    //获取当前实例测量得出的总运行时间
    Console.WriteLine("用时:"+sw.Elapsed); 
    Console.Read();

    C#使用Stopwatch精确测量运行时间

    一般测量时间间隔使用的是DateTime.Now实例的DateTime.Ticks当前属性,想要精确测量一个操作的运行时间就只能使用Stopwatch类计时了。

    Stopwatch计时精度取决于硬件,如果安装的硬件和操作系统支持高分辨率性能计数器, 则Stopwatch类将使用该计数器来测量运行时间。否则,Stopwatch类将使用系统计时器来测量运行时间。

    测量耗时操作的运行时间

                Stopwatch stopWatch = new Stopwatch();
                stopWatch.Start();
                Thread.Sleep(5000); // 耗时操作
                stopWatch.Stop();
                
    
                // 将经过的时间作为TimeSpan值
                TimeSpan ts = stopWatch.Elapsed;
                // 格式和显示时间值
                string elapsedTime = String.Format("{0:00}:{1:00}:{2:00}.{3:000}-{4:000}", ts.Hours, ts.Minutes, ts.Seconds, ts.Milliseconds, (ts.Ticks * 100 / 1000)%1000);
                Console.WriteLine("RunTime " + elapsedTime);
    
                // 将经过的时间作为毫秒数
                long mSeconds = stopWatch.ElapsedMilliseconds;
                Console.WriteLine("RunTime(ms) " + mSeconds);
    
                // 获取经过时间的计时器刻度
                // 也可在耗时操作前后使用Stopwatch.GetTimestamp()各获取1个Ticks值,然后相减得到耗时操作花费的计时器刻度
                // 计时器采用的计时方式不同,tick的时间单位不同
                long tick = stopWatch.ElapsedTicks;
                Console.WriteLine("RunTime(tick) " + tick);
    
                if (Stopwatch.IsHighResolution)
                {
                    // 计时器刻度是高性能计时器滴答数
                    Console.WriteLine("使用系统高分辨率性能计数器计时:");
                    Console.WriteLine("  RunTime(ns) " +tick* ((1000L * 1000L * 1000L)/ Stopwatch.Frequency));
                }
                else
                {
                    // 计时器刻度是DateTime.Now实例的DateTime.Ticks当前属性
                    Console.WriteLine("使用DateTime类计时:");
                    Console.WriteLine("  RunTime(ns) " + tick * 100);
                }

    查看Stopwatch计时器的计时方式

            /// <summary>
            /// 显示计时器属性
            /// </summary>
            public static void DisplayTimerProperties()
            {
                // 显示定时器频率和分辨率
                if (Stopwatch.IsHighResolution)
                {
                    Console.WriteLine("操作使用系统高分辨率性能计数器计时");
                }
                else
                {
                    Console.WriteLine("操作使用DateTime类计时");
                }
    
                long frequency = Stopwatch.Frequency;
                Console.WriteLine("  计时器频率,单位为每秒滴答数 = {0}",
                    frequency);
                long nanosecPerTick = (1000L * 1000L * 1000L) / frequency;
                Console.WriteLine("  计时器分辨率为 {0} 纳秒/滴答",
                    nanosecPerTick);
            }

    附上官网上的一个测试实例

            private static void TimeOperations()
            {
                long nanosecPerTick = (1000L * 1000L * 1000L) / Stopwatch.Frequency;
                const long numIterations = 10000;
    
                // 定义操作标题名称
                String[] operationNames = {"操作: Int32.Parse(\"0\")",
                                               "操作: Int32.TryParse(\"0\")",
                                               "操作: Int32.Parse(\"a\")",
                                               "操作: Int32.TryParse(\"a\")"};
                Console.WriteLine();
                Console.WriteLine("注:1ticks=100ns,1s=1000ms,1ms=1000us,1us=1000ns");
    
                // 从字符串解析整数的四种不同实现
                for (int operation = 0; operation <= 3; operation++)
                {
                    // 定义操作统计的变量
                    long numTicks = 0;
                    long numRollovers = 0;
                    long maxTicks = 0;
                    long minTicks = Int64.MaxValue;
                    int indexFastest = -1;
                    int indexSlowest = -1;
                    long milliSec = 0;
    
                    Stopwatch time10kOperations = Stopwatch.StartNew();
    
                    // 运行当前操作10001次。
                    // 第一次执行时间将被丢弃,因为它可能会扭曲平均时间。
                    for (int i = 0; i <= numIterations; i++)
                    {
                        long ticksThisTime = 0;
                        int inputNum;
                        Stopwatch timePerParse;
    
                        switch (operation)
                        {
                            case 0:
                                // 使用try-catch语句分析有效整数
                                // 启动新的秒表计时器
                                timePerParse = Stopwatch.StartNew();
                                try
                                {
                                    inputNum = Int32.Parse("0");
                                }
                                catch (FormatException)
                                {
                                    inputNum = 0;
                                }
    
                                // 停止计时器,并保存操作所用的计时ticks
    
                                timePerParse.Stop();
                                ticksThisTime = timePerParse.ElapsedTicks;
                                break;
                            case 1:                           
                                timePerParse = Stopwatch.StartNew();
                                if (!Int32.TryParse("0", out inputNum))
                                {
                                    inputNum = 0;
                                }
                                timePerParse.Stop();
                                ticksThisTime = timePerParse.ElapsedTicks;
                                break;
                            case 2:                            
                                timePerParse = Stopwatch.StartNew();
                                try
                                {
                                    inputNum = Int32.Parse("a");
                                }
                                catch (FormatException)
                                {
                                    inputNum = 0;
                                }
                                timePerParse.Stop();
                                ticksThisTime = timePerParse.ElapsedTicks;
                                break;
                            case 3:                           
                                timePerParse = Stopwatch.StartNew();
                                if (!Int32.TryParse("a", out inputNum))
                                {
                                    inputNum = 0;
                                }                            
                                timePerParse.Stop();
                                ticksThisTime = timePerParse.ElapsedTicks;
                                break;
                            default:
                                break;
                        }
                        // 跳过第一个操作的时间,以防它导致一次性性能下降。
                        if (i == 0)
                        {
                            time10kOperations.Reset();
                            time10kOperations.Start();
                        }
                        else
                        {
                            // 更新迭代1-10001的操作统计信息。
                            if (maxTicks < ticksThisTime)
                            {
                                indexSlowest = i;
                                maxTicks = ticksThisTime;
                            }
                            if (minTicks > ticksThisTime)
                            {
                                indexFastest = i;
                                minTicks = ticksThisTime;
                            }
                            numTicks += ticksThisTime;
                            if (numTicks < ticksThisTime)
                            {
                                // Keep track of rollovers.
                                numRollovers++;
                            }
                        }
                    }
    
                    // 显示10000次迭代的统计信息
                    time10kOperations.Stop();
                    milliSec = time10kOperations.ElapsedMilliseconds;
    
                    Console.WriteLine();
                    Console.WriteLine("{0} 统计:", operationNames[operation]);
                    Console.WriteLine("  最慢时间:  第{0}/{1}次操作,时间为{2} ticks",
                        indexSlowest, numIterations, maxTicks);
                    Console.WriteLine("  最快时间:  第{0}/{1}次操作,时间为{2} ticks",
                        indexFastest, numIterations, minTicks);
                    Console.WriteLine("  平均时间:  {0} ticks = {1} ns",
                        numTicks / numIterations,
                        (numTicks * nanosecPerTick) / numIterations);
                    Console.WriteLine("  {0} 次操作的总时间: {1} ms",
                        numIterations, milliSec);
                }
            }

    到此,相信大家对“C#中的Stopwatch如何使用”有了更深的了解,不妨来实际操作一番吧!这里是亿速云网站,更多相关内容可以进入相关频道进行查询,关注我们,继续学习!

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