Stopwatch Class
Definition
Important
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Provides a set of methods and properties that you can use to accurately measure elapsed time.
public ref class Stopwatchpublic class Stopwatchtype Stopwatch = classPublic Class Stopwatch- Inheritance
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Stopwatch
Examples
The following example demonstrates how to use the Stopwatch class to determine the execution time for an application.
using System;
using System.Diagnostics;
using System.Threading;
class Program
{
static void Main(string[] args)
{
Stopwatch stopWatch = new Stopwatch();
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);
}
}
Imports System.Diagnostics
Imports System.Threading
Class Program
Shared Sub Main(ByVal args() As String)
Dim stopWatch As New Stopwatch()
stopWatch.Start()
Thread.Sleep(10000)
stopWatch.Stop()
' Get the elapsed time as a TimeSpan value.
Dim ts As TimeSpan = stopWatch.Elapsed
' Format and display the TimeSpan value.
Dim elapsedTime As String = String.Format("{0:00}:{1:00}:{2:00}.{3:00}", ts.Hours, ts.Minutes, ts.Seconds, ts.Milliseconds / 10)
Console.WriteLine( "RunTime " + elapsedTime)
End Sub
End Class
The following example demonstrates the use of the Stopwatch class to calculate performance data.
#using <System.dll>
using namespace System;
using namespace System::Diagnostics;
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." );
}
Int64 frequency = Stopwatch::Frequency;
Console::WriteLine( " Timer frequency in ticks per second = {0}", frequency );
Int64 nanosecPerTick = (1000L * 1000L * 1000L) / frequency;
Console::WriteLine( " Timer is accurate within {0} nanoseconds", nanosecPerTick );
}
void TimeOperations()
{
Int64 nanosecPerTick = (1000L * 1000L * 1000L) / Stopwatch::Frequency;
const long numIterations = 10000;
// Define the operation title names.
array<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.
Int64 numTicks = 0;
Int64 numRollovers = 0;
Int64 maxTicks = 0;
Int64 minTicks = Int64::MaxValue;
int indexFastest = -1;
int indexSlowest = -1;
Int64 milliSec = 0;
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++ )
{
Int64 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 = Int32::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 ( !Int32::TryParse( "0", 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 = Int32::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 ( !Int32::TryParse( "a", 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 1-10001.
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();
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 );
}
}
int main()
{
DisplayTimerProperties();
Console::WriteLine();
Console::WriteLine( "Press the Enter key to begin:" );
Console::ReadLine();
Console::WriteLine();
TimeOperations();
}
using System;
using System.Diagnostics;
namespace StopWatchSample
{
class OperationsTimer
{
public static void Main()
{
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 = Int64.MaxValue;
int indexFastest = -1;
int indexSlowest = -1;
long milliSec = 0;
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 = Int32.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 (!Int32.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 = Int32.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 (!Int32.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();
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);
}
}
}
}
Imports System.Diagnostics
Class OperationsTimer
Public Shared Sub Main()
DisplayTimerProperties()
Console.WriteLine()
Console.WriteLine("Press the Enter key to begin:")
Console.ReadLine()
Console.WriteLine()
TimeOperations()
End Sub
Public Shared Sub DisplayTimerProperties()
' Display the timer frequency and resolution.
If Stopwatch.IsHighResolution Then
Console.WriteLine("Operations timed using the system's high-resolution performance counter.")
Else
Console.WriteLine("Operations timed using the DateTime class.")
End If
Dim frequency As Long = Stopwatch.Frequency
Console.WriteLine(" Timer frequency in ticks per second = {0}", frequency)
Dim nanosecPerTick As Long = 1000000000 / frequency
Console.WriteLine(" Timer is accurate within {0} nanoseconds", nanosecPerTick)
End Sub
Private Shared Sub TimeOperations()
Dim nanosecPerTick As Long = 1000000000 / Stopwatch.Frequency
Const numIterations As Long = 10000
' Define the operation title names.
Dim operationNames As String() = _
{"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.
Dim operation As Integer
For operation = 0 To 3
' Define variables for operation statistics.
Dim numTicks As Long = 0
Dim numRollovers As Long = 0
Dim maxTicks As Long = 0
Dim minTicks As Long = Int64.MaxValue
Dim indexFastest As Integer = - 1
Dim indexSlowest As Integer = - 1
Dim milliSec As Long = 0
Dim time10kOperations As Stopwatch = Stopwatch.StartNew()
' Run the current operation 10001 times.
' The first execution time will be tossed
' out, since it can skew the average time.
Dim i As Integer
For i = 0 To numIterations
Dim ticksThisTime As Long = 0
Dim inputNum As Integer
Dim timePerParse As Stopwatch
Select Case operation
Case 0
' Parse a valid integer using
' a try-catch statement.
' Start a new stopwatch timer.
timePerParse = Stopwatch.StartNew()
Try
inputNum = Int32.Parse("0")
Catch e As FormatException
inputNum = 0
End Try
' Stop the timer, and save the
' elapsed ticks for the operation.
timePerParse.Stop()
ticksThisTime = timePerParse.ElapsedTicks
Case 1
' Parse a valid integer using
' the TryParse statement.
' Start a new stopwatch timer.
timePerParse = Stopwatch.StartNew()
If Not Int32.TryParse("0", inputNum) Then
inputNum = 0
End If
' Stop the timer, and save the
' elapsed ticks for the operation.
timePerParse.Stop()
ticksThisTime = timePerParse.ElapsedTicks
Case 2
' Parse an invalid value using
' a try-catch statement.
' Start a new stopwatch timer.
timePerParse = Stopwatch.StartNew()
Try
inputNum = Int32.Parse("a")
Catch e As FormatException
inputNum = 0
End Try
' Stop the timer, and save the
' elapsed ticks for the operation.
timePerParse.Stop()
ticksThisTime = timePerParse.ElapsedTicks
Case 3
' Parse an invalid value using
' the TryParse statement.
' Start a new stopwatch timer.
timePerParse = Stopwatch.StartNew()
If Not Int32.TryParse("a", inputNum) Then
inputNum = 0
End If
' Stop the timer, and save the
' elapsed ticks for the operation.
timePerParse.Stop()
ticksThisTime = timePerParse.ElapsedTicks
Case Else
End Select
' Skip over the time for the first operation,
' just in case it caused a one-time
' performance hit.
If i = 0 Then
time10kOperations.Reset()
time10kOperations.Start()
Else
' Update operation statistics
' for iterations 1-10001.
If maxTicks < ticksThisTime Then
indexSlowest = i
maxTicks = ticksThisTime
End If
If minTicks > ticksThisTime Then
indexFastest = i
minTicks = ticksThisTime
End If
numTicks += ticksThisTime
If numTicks < ticksThisTime Then
' Keep track of rollovers.
numRollovers += 1
End If
End If
Next i
' Display the statistics for 10000 iterations.
time10kOperations.Stop()
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)
Next operation
End Sub
End Class
Remarks
A Stopwatch instance can measure elapsed time for one interval, or the total of elapsed time across multiple intervals. In a typical Stopwatch scenario, you call the Start method, then eventually call the Stop method, and then you check elapsed time using the Elapsed property.
A Stopwatch instance is either running or stopped; use IsRunning to determine the current state of a Stopwatch. Use Start to begin measuring elapsed time; use Stop to stop measuring elapsed time. Query the elapsed time value through the properties Elapsed, ElapsedMilliseconds, or ElapsedTicks. You can query the elapsed time properties while the instance is running or stopped. The elapsed time properties steadily increase while the Stopwatch is running; they remain constant when the instance is stopped.
By default, the elapsed time value of a Stopwatch instance equals the total of all measured time intervals. Each call to Start begins counting at the cumulative elapsed time; each call to Stop ends the current interval measurement and freezes the cumulative elapsed time value. Use the Reset method to clear the cumulative elapsed time in an existing Stopwatch instance.
The Stopwatch measures elapsed time by counting timer ticks in the underlying timer mechanism. If the installed hardware and operating system support a high-resolution performance counter, then the Stopwatch class uses that counter to measure elapsed time. Otherwise, the Stopwatch class uses the system timer to measure elapsed time. Use the Frequency and IsHighResolution fields to determine the precision and resolution of the Stopwatch timing implementation.
The Stopwatch class assists the manipulation of timing-related performance counters within managed code. Specifically, the Frequency field and GetTimestamp method can be used in place of the unmanaged Windows APIs QueryPerformanceFrequency and QueryPerformanceCounter.
Note
On a multiprocessor computer, it does not matter which processor the thread runs on. However, because of bugs in the BIOS or the Hardware Abstraction Layer (HAL), you can get different timing results on different processors. To specify processor affinity for a thread, use the ProcessThread.ProcessorAffinity method.
Constructors
| Stopwatch() |
Initializes a new instance of the Stopwatch class. |
Fields
| Frequency |
Gets the frequency of the timer as the number of ticks per second. This field is read-only. |
| IsHighResolution |
Indicates whether the timer is based on a high-resolution performance counter. This field is read-only. |
Properties
| Elapsed |
Gets the total elapsed time measured by the current instance. |
| ElapsedMilliseconds |
Gets the total elapsed time measured by the current instance, in milliseconds. |
| ElapsedTicks |
Gets the total elapsed time measured by the current instance, in timer ticks. |
| IsRunning |
Gets a value indicating whether the Stopwatch timer is running. |
Methods
| Equals(Object) |
Determines whether the specified object is equal to the current object. (Inherited from Object) |
| GetElapsedTime(Int64, Int64) |
Gets the elapsed time between two timestamps retrieved using GetTimestamp(). |
| GetElapsedTime(Int64) |
Gets the elapsed time since the |
| GetHashCode() |
Serves as the default hash function. (Inherited from Object) |
| GetTimestamp() |
Gets the current number of ticks in the timer mechanism. |
| GetType() |
Gets the Type of the current instance. (Inherited from Object) |
| MemberwiseClone() |
Creates a shallow copy of the current Object. (Inherited from Object) |
| Reset() |
Stops time interval measurement and resets the elapsed time to zero. |
| Restart() |
Stops time interval measurement, resets the elapsed time to zero, and starts measuring elapsed time. |
| Start() |
Starts, or resumes, measuring elapsed time for an interval. |
| StartNew() |
Initializes a new Stopwatch instance, sets the elapsed time property to zero, and starts measuring elapsed time. |
| Stop() |
Stops measuring elapsed time for an interval. |
| ToString() |
Returns the Elapsed time as a string. |
| ToString() |
Returns a string that represents the current object. (Inherited from Object) |
