一、Stopwatch 类
提供一组方法和属性，可用于准确地测量运行时间。
public class Stopwatch使用 Stopwatch 类来确定应用程序的执行时间。
// 使用 Stopwatch 类来确定应用程序的执行时间
using System.Diagnostics;
class Program
{
static void Main(string[] args)
{
ArgumentNullException.ThrowIfNull(args);
Stopwatch stopWatch = new();
stopWatch.Start();
Thread.Sleep(10000);
stopWatch.Stop();
// Get the elapsed time as a TimeSpan value.
TimeSpan ts = stopWatch.Elapsed;
// Format and display the TimeSpan value.
string elapsedTime = String.Format("{0:00}:{1:00}:{2:00}.{3:00}",
ts.Hours, ts.Minutes, ts.Seconds,
ts.Milliseconds / 10);
Console.WriteLine("RunTime " + elapsedTime);
}
}
//运行结果：
/*
RunTime 00:00:10.01
*/
// 使用 Stopwatch 类来计算性能数据。
using System.Diagnostics;
namespace StopWatchSample
{
class OperationsTimer
{
public static void Main(string[] args)
{
ArgumentNullException.ThrowIfNull(args);
DisplayTimerProperties();
Console.WriteLine();
Console.WriteLine("Press the Enter key to begin:");
Console.ReadLine();
Console.WriteLine();
TimeOperations();
}
public static void DisplayTimerProperties()
{
// Display the timer frequency and resolution.
if (Stopwatch.IsHighResolution)
{
Console.WriteLine("Operations timed using the system's high-resolution performance counter.");
}
else
{
Console.WriteLine("Operations timed using the DateTime class.");
}
long frequency = Stopwatch.Frequency;
Console.WriteLine(" Timer frequency in ticks per second = {0}",frequency);
long nanosecPerTick = (1000L * 1000L * 1000L) / frequency;
Console.WriteLine(" Timer is accurate within {0} nanoseconds",nanosecPerTick);
}
private static void TimeOperations()
{
long nanosecPerTick = (1000L * 1000L * 1000L) / Stopwatch.Frequency;
const long numIterations = 10000;
// Define the operation title names.
string[] operationNames = {"Operation: Int32.Parse(\"0\")",
"Operation: Int32.TryParse(\"0\")",
"Operation: Int32.Parse(\"a\")",
"Operation: Int32.TryParse(\"a\")"};
// Time four different implementations for parsing
// an integer from a string.
for (int operation = 0; operation <= 3; operation++)
{
// Define variables for operation statistics.
long numTicks = 0;
long numRollovers = 0;
long maxTicks = 0;
long minTicks = long.MaxValue;
int indexFastest = -1;
int indexSlowest = -1;
Stopwatch time10kOperations = Stopwatch.StartNew();
// Run the current operation 10001 times.
// The first execution time will be tossed
// out, since it can skew the average time.
for (int i = 0; i <= numIterations; i++)
{
long ticksThisTime = 0;
int inputNum;
Stopwatch timePerParse;
switch (operation)
{
case 0:
// Parse a valid integer using
// a try-catch statement.
// Start a new stopwatch timer.
timePerParse = Stopwatch.StartNew();
try
{
inputNum = int.Parse("0");
}
catch (FormatException)
{
inputNum = 0;
}
// Stop the timer, and save the
// elapsed ticks for the operation.
timePerParse.Stop();
ticksThisTime = timePerParse.ElapsedTicks;
break;
case 1:
// Parse a valid integer using
// the TryParse statement.
// Start a new stopwatch timer.
timePerParse = Stopwatch.StartNew();
if (!int.TryParse("0", out inputNum))
{
inputNum = 0;
}
// Stop the timer, and save the
// elapsed ticks for the operation.
timePerParse.Stop();
ticksThisTime = timePerParse.ElapsedTicks;
break;
case 2:
// Parse an invalid value using
// a try-catch statement.
// Start a new stopwatch timer.
timePerParse = Stopwatch.StartNew();
try
{
inputNum = int.Parse("a");
}
catch (FormatException)
{
inputNum = 0;
}
// Stop the timer, and save the
// elapsed ticks for the operation.
timePerParse.Stop();
ticksThisTime = timePerParse.ElapsedTicks;
break;
case 3:
// Parse an invalid value using
// the TryParse statement.
// Start a new stopwatch timer.
timePerParse = Stopwatch.StartNew();
if (!int.TryParse("a", out inputNum))
{
inputNum = 0;
}
// Stop the timer, and save the
// elapsed ticks for the operation.
timePerParse.Stop();
ticksThisTime = timePerParse.ElapsedTicks;
break;
default:
break;
}
// Skip over the time for the first operation,
// just in case it caused a one-time
// performance hit.
if (i == 0)
{
time10kOperations.Reset();
time10kOperations.Start();
}
else
{
// Update operation statistics
// for iterations 1-10000.
if (maxTicks < ticksThisTime)
{
indexSlowest = i;
maxTicks = ticksThisTime;
}
if (minTicks > ticksThisTime)
{
indexFastest = i;
minTicks = ticksThisTime;
}
numTicks += ticksThisTime;
if (numTicks < ticksThisTime)
{
// Keep track of rollovers.
numRollovers++;
}
}
}
// Display the statistics for 10000 iterations.
time10kOperations.Stop();
long milliSec = time10kOperations.ElapsedMilliseconds;
Console.WriteLine();
Console.WriteLine("{0} Summary:", operationNames[operation]);
Console.WriteLine(" Slowest time: #{0}/{1} = {2} ticks",
indexSlowest, numIterations, maxTicks);
Console.WriteLine(" Fastest time: #{0}/{1} = {2} ticks",
indexFastest, numIterations, minTicks);
Console.WriteLine(" Average time: {0} ticks = {1} nanoseconds",
numTicks / numIterations,
(numTicks * nanosecPerTick) / numIterations);
Console.WriteLine(" Total time looping through {0} operations: {1} milliseconds",
numIterations, milliSec);
}
}
}
}
//运行结果：
/*
Operations timed using the system's high-resolution performance counter.
Timer frequency in ticks per second = 10000000
Timer is accurate within 100 nanoseconds
*/1.Stopwatch.Start 方法
开始或继续测量某个时间间隔的运行时间。
前例中有示例。
public void Start ();2.Stopwatch.Stop 方法
停止测量某个时间间隔的运行时间。
public void Stop ();前例中有示例。
