Stopwatch Classe
Definição
Importante
Algumas informações se referem a produtos de pré-lançamento que podem ser substancialmente modificados antes do lançamento. A Microsoft não oferece garantias, expressas ou implícitas, das informações aqui fornecidas.
Fornece um conjunto de métodos e propriedades que você pode usar para medir com precisão o tempo decorrido.
public ref class Stopwatchpublic class Stopwatchtype Stopwatch = classPublic Class Stopwatch- Herança
-
Stopwatch
Exemplos
O exemplo a seguir demonstra como usar a Stopwatch classe para determinar o tempo de execução de um aplicativo.
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
O exemplo a seguir demonstra o uso da classe para calcular dados de Stopwatch desempenho.
#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
Comentários
Uma Stopwatch instância pode medir o tempo decorrido para um intervalo ou o total de tempo decorrido em vários intervalos. Em um cenário típicoStopwatch, você chama o Start método e, eventualmente, chama o Stop método e marcar tempo decorrido usando a Elapsed propriedade .
Uma Stopwatch instância está em execução ou interrompida; use IsRunning para determinar o estado atual de um Stopwatch. Use Start para começar a medir o tempo decorrido; use Stop para parar de medir o tempo decorrido. Consulte o valor de tempo decorrido por meio das propriedades Elapsed, ElapsedMillisecondsou ElapsedTicks. Você pode consultar as propriedades de tempo decorrido enquanto a instância está em execução ou interrompida. As propriedades de tempo decorrido aumentam constantemente enquanto o Stopwatch está em execução; elas permanecem constantes quando a instância é interrompida.
Por padrão, o valor de tempo decorrido de uma Stopwatch instância é igual ao total de todos os intervalos de tempo medidos. Cada chamada para começa a Start contar no tempo decorrido cumulativo; cada chamada para Stop termina a medida de intervalo atual e congela o valor de tempo decorrido cumulativo. Use o Reset método para limpar o tempo decorrido cumulativo em uma instância existente Stopwatch .
O Stopwatch tempo decorrido mede a contagem de tiques de temporizador no mecanismo de temporizador subjacente. Se o hardware instalado e o sistema operacional derem suporte a um contador de desempenho de alta resolução, a Stopwatch classe usará esse contador para medir o tempo decorrido. Caso contrário, a Stopwatch classe usa o temporizador do sistema para medir o tempo decorrido. Use os Frequency campos e IsHighResolution para determinar a precisão e a resolução da implementação de Stopwatch tempo.
A Stopwatch classe auxilia na manipulação de contadores de desempenho relacionados ao tempo dentro do código gerenciado. Especificamente, o campo e GetTimestamp o Frequency método podem ser usados no lugar das APIs QueryPerformanceFrequency não gerenciadas do Windows e QueryPerformanceCounter.
Observação
Em um computador multiprocessador, não importa em qual processador o thread é executado. No entanto, devido a bugs no BIOS ou na HAL (Camada de Abstração de Hardware), você pode obter resultados de tempo diferentes em processadores diferentes. Para especificar a afinidade do processador para um thread, use o ProcessThread.ProcessorAffinity método .
Construtores
| Stopwatch() |
Inicializa uma nova instância da classe Stopwatch. |
Campos
| Frequency |
Obtém a frequência do temporizador como o número de tiques por segundo. Este campo é somente leitura. |
| IsHighResolution |
Indica se o temporizador é baseado em um contador de desempenho de alta resolução. Este campo é somente leitura. |
Propriedades
| Elapsed |
Obtém o tempo total decorrido, medido pela instância atual. |
| ElapsedMilliseconds |
Obtém o tempo total decorrido, medido pela instância atual, em milissegundos. |
| ElapsedTicks |
Obtém o tempo total decorrido, medido pela instância atual, em tiques do temporizador. |
| IsRunning |
Obtém um valor que indica se o temporizador de Stopwatch está em execução. |
Métodos
| Equals(Object) |
Determina se o objeto especificado é igual ao objeto atual. (Herdado de Object) |
| GetElapsedTime(Int64) |
Obtém o tempo decorrido desde o |
| GetElapsedTime(Int64, Int64) |
Obtém o tempo decorrido entre dois carimbos de data/hora recuperados usando GetTimestamp(). |
| GetHashCode() |
Serve como a função de hash padrão. (Herdado de Object) |
| GetTimestamp() |
Obtém o número de tiques atual no mecanismo de temporizador. |
| GetType() |
Obtém o Type da instância atual. (Herdado de Object) |
| MemberwiseClone() |
Cria uma cópia superficial do Object atual. (Herdado de Object) |
| Reset() |
Interrompe a medida de intervalo de tempo e redefine o tempo decorrido para zero. |
| Restart() |
Interrompe a medida de tempo de intervalo, redefine o tempo decorrido para zero e começa a medir o tempo decorrido. |
| Start() |
Inicia ou retoma a medição do tempo decorrido de um intervalo. |
| StartNew() |
Inicializa uma nova instância Stopwatch, define a propriedade de tempo decorrido como zero e começa a medir o tempo decorrido. |
| Stop() |
Para a medição do tempo decorrido de um intervalo. |
| ToString() |
Retorna o Elapsed tempo como uma cadeia de caracteres. |
| ToString() |
Retorna uma cadeia de caracteres que representa o objeto atual. (Herdado de Object) |
