PerformanceCounter.IncrementBy(Int64) Method
Definition
Important
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Increments or decrements the value of the associated performance counter by a specified amount through an efficient atomic operation.
public:
long IncrementBy(long value);public long IncrementBy (long value);member this.IncrementBy : int64 -> int64Public Function IncrementBy (value As Long) As LongParameters
- value
- Int64
The value to increment by. (A negative value decrements the counter.)
Returns
The new counter value.
Exceptions
The counter is read-only, so the application cannot increment it.
-or-
The instance is not correctly associated with a performance counter.
-or-
The InstanceLifetime property is set to Process when using global shared memory.
An error occurred when accessing a system API.
Examples
The following code example demonstrates how to use the IncrementBy method to add increments to a counter. This code example is part of a larger example for the PerformanceCounter class.
void CollectSamples( ArrayList^ samplesList, PerformanceCounter^ PC, PerformanceCounter^ BPC )
{
Random^ r = gcnew Random( DateTime::Now.Millisecond );
// Loop for the samples.
for ( int j = 0; j < 100; j++ )
{
int value = r->Next( 1, 10 );
Console::Write( "{0} = {1}", j, value );
PC->IncrementBy( value );
BPC->Increment();
if ( (j % 10) == 9 )
{
OutputSample( PC->NextSample() );
samplesList->Add( PC->NextSample() );
}
else
Console::WriteLine();
System::Threading::Thread::Sleep( 50 );
}
}
private static void CollectSamples(ArrayList samplesList)
{
Random r = new Random( DateTime.Now.Millisecond );
// Loop for the samples.
for (int j = 0; j < 100; j++)
{
int value = r.Next(1, 10);
Console.Write(j + " = " + value);
avgCounter64Sample.IncrementBy(value);
avgCounter64SampleBase.Increment();
if ((j % 10) == 9)
{
OutputSample(avgCounter64Sample.NextSample());
samplesList.Add( avgCounter64Sample.NextSample() );
}
else
{
Console.WriteLine();
}
System.Threading.Thread.Sleep(50);
}
}
Private Shared Sub CollectSamples(ByVal samplesList As ArrayList)
Dim r As New Random(DateTime.Now.Millisecond)
' Loop for the samples.
Dim j As Integer
For j = 0 To 99
Dim value As Integer = r.Next(1, 10)
Console.Write(j.ToString() + " = " + value.ToString())
avgCounter64Sample.IncrementBy(value)
avgCounter64SampleBase.Increment()
If j Mod 10 = 9 Then
OutputSample(avgCounter64Sample.NextSample())
samplesList.Add(avgCounter64Sample.NextSample())
Else
Console.WriteLine()
End If
System.Threading.Thread.Sleep(50)
Next j
End Sub
Remarks
You can write only to custom counters. All system counters are read-only.
Note
The Increment, IncrementBy, and Decrement methods use interlocks to update the counter value. This helps keep the counter value accurate in multithreaded or multiprocess scenarios, but also results in a performance penalty. If you do not need the accuracy that interlocked operations provide, you can update the RawValue property directly for up to a 5 times performance improvement. However, in multithreaded scenarios, some updates to the counter value might be ignored, resulting in inaccurate data.
Note
If the value for the InstanceLifetime property is Process and the performance counter category was created with .NET Framework version 1.0 or 1.1, an InvalidOperationException is thrown. Performance counter categories created with earlier versions use global shared memory, and the value for InstanceLifetime must be Global. If the category is not used by applications running on versions 1.0 or 1.1 of the .NET Framework, delete and recreate the category.
Applies to
Thread Safety
This method is thread safe.
