GC.RegisterForFullGCNotification(Int32, Int32) Método
Definición
Importante
Parte de la información hace referencia a la versión preliminar del producto, que puede haberse modificado sustancialmente antes de lanzar la versión definitiva. Microsoft no otorga ninguna garantía, explícita o implícita, con respecto a la información proporcionada aquí.
Especifica que debe emitirse una notificación de recolección de elementos no utilizados cuando las condiciones favorecen la recolección completa de elementos no utilizados y cuando se ha completado la recolección.
public:
static void RegisterForFullGCNotification(int maxGenerationThreshold, int largeObjectHeapThreshold);public static void RegisterForFullGCNotification (int maxGenerationThreshold, int largeObjectHeapThreshold);[System.Security.SecurityCritical]
public static void RegisterForFullGCNotification (int maxGenerationThreshold, int largeObjectHeapThreshold);static member RegisterForFullGCNotification : int * int -> unit[<System.Security.SecurityCritical>]
static member RegisterForFullGCNotification : int * int -> unitPublic Shared Sub RegisterForFullGCNotification (maxGenerationThreshold As Integer, largeObjectHeapThreshold As Integer)Parámetros
- maxGenerationThreshold
- Int32
Número comprendido entre 1 y 99 que especifica cuándo debe emitirse la notificación basándose en los objetos asignados en la generación 2.
- largeObjectHeapThreshold
- Int32
Un número comprendido entre 1 y 99 que especifica cuándo debe emitirse la notificación basándose en los objetos asignados en el montón de objetos grandes.
- Atributos
Excepciones
maxGenerationThreshold o largeObjectHeapThreshold no está entre 1 y 99.
Este miembro no está disponible cuando la recolección de elementos no utilizados simultánea está habilitada. Vea la configuración en tiempo de ejecución <gcConcurrent> para obtener información sobre cómo deshabilitar la recolección de elementos no utilizados simultánea.
Ejemplos
En el ejemplo siguiente se muestra cómo registrar una notificación de recolección de elementos no utilizados e iniciar un subproceso para supervisar el estado de la notificación de recolección de elementos no utilizados. Este ejemplo de código forma parte de un ejemplo más grande proporcionado para el tema Notificaciones de recolección de elementos no utilizados.
using namespace System;
using namespace System::Collections::Generic;
using namespace System::Threading;
namespace GCNotify
{
ref class Program
{
private:
// Variable for continual checking in the
// While loop in the WaitForFullGCProc method.
static bool checkForNotify = false;
// Variable for suspending work
// (such servicing allocated server requests)
// after a notification is received and then
// resuming allocation after inducing a garbage collection.
static bool bAllocate = false;
// Variable for ending the example.
static bool finalExit = false;
// Collection for objects that
// simulate the server request workload.
static List<array<Byte>^>^ load = gcnew List<array<Byte>^>();
public:
static void Main()
{
try
{
// Register for a notification.
GC::RegisterForFullGCNotification(10, 10);
Console::WriteLine("Registered for GC notification.");
checkForNotify = true;
bAllocate = true;
// Start a thread using WaitForFullGCProc.
Thread^ thWaitForFullGC = gcnew Thread(gcnew ThreadStart(&WaitForFullGCProc));
thWaitForFullGC->Start();
// While the thread is checking for notifications in
// WaitForFullGCProc, create objects to simulate a server workload.
try
{
int lastCollCount = 0;
int newCollCount = 0;
while (true)
{
if (bAllocate)
{
load->Add(gcnew array<Byte>(1000));
newCollCount = GC::CollectionCount(2);
if (newCollCount != lastCollCount)
{
// Show collection count when it increases:
Console::WriteLine("Gen 2 collection count: {0}", GC::CollectionCount(2).ToString());
lastCollCount = newCollCount;
}
// For ending the example (arbitrary).
if (newCollCount == 500)
{
finalExit = true;
checkForNotify = false;
break;
}
}
}
}
catch (OutOfMemoryException^)
{
Console::WriteLine("Out of memory.");
}
finalExit = true;
checkForNotify = false;
GC::CancelFullGCNotification();
}
catch (InvalidOperationException^ invalidOp)
{
Console::WriteLine("GC Notifications are not supported while concurrent GC is enabled.\n"
+ invalidOp->Message);
}
}
public:
static void OnFullGCApproachNotify()
{
Console::WriteLine("Redirecting requests.");
// Method that tells the request queuing
// server to not direct requests to this server.
RedirectRequests();
// Method that provides time to
// finish processing pending requests.
FinishExistingRequests();
// This is a good time to induce a GC collection
// because the runtime will induce a full GC soon.
// To be very careful, you can check precede with a
// check of the GC.GCCollectionCount to make sure
// a full GC did not already occur since last notified.
GC::Collect();
Console::WriteLine("Induced a collection.");
}
public:
static void OnFullGCCompleteEndNotify()
{
// Method that informs the request queuing server
// that this server is ready to accept requests again.
AcceptRequests();
Console::WriteLine("Accepting requests again.");
}
public:
static void WaitForFullGCProc()
{
while (true)
{
// CheckForNotify is set to true and false in Main.
while (checkForNotify)
{
// Check for a notification of an approaching collection.
GCNotificationStatus s = GC::WaitForFullGCApproach();
if (s == GCNotificationStatus::Succeeded)
{
Console::WriteLine("GC Notifiction raised.");
OnFullGCApproachNotify();
}
else if (s == GCNotificationStatus::Canceled)
{
Console::WriteLine("GC Notification cancelled.");
break;
}
else
{
// This can occur if a timeout period
// is specified for WaitForFullGCApproach(Timeout)
// or WaitForFullGCComplete(Timeout)
// and the time out period has elapsed.
Console::WriteLine("GC Notification not applicable.");
break;
}
// Check for a notification of a completed collection.
s = GC::WaitForFullGCComplete();
if (s == GCNotificationStatus::Succeeded)
{
Console::WriteLine("GC Notification raised.");
OnFullGCCompleteEndNotify();
}
else if (s == GCNotificationStatus::Canceled)
{
Console::WriteLine("GC Notification cancelled.");
break;
}
else
{
// Could be a time out.
Console::WriteLine("GC Notification not applicable.");
break;
}
}
Thread::Sleep(500);
// FinalExit is set to true right before
// the main thread cancelled notification.
if (finalExit)
{
break;
}
}
}
private:
static void RedirectRequests()
{
// Code that sends requests
// to other servers.
// Suspend work.
bAllocate = false;
}
static void FinishExistingRequests()
{
// Code that waits a period of time
// for pending requests to finish.
// Clear the simulated workload.
load->Clear();
}
static void AcceptRequests()
{
// Code that resumes processing
// requests on this server.
// Resume work.
bAllocate = true;
}
};
}
int main()
{
GCNotify::Program::Main();
}
using System;
using System.Collections.Generic;
using System.Threading;
namespace GCNotify
{
class Program
{
// Variable for continual checking in the
// While loop in the WaitForFullGCProc method.
static bool checkForNotify = false;
// Variable for suspending work
// (such servicing allocated server requests)
// after a notification is received and then
// resuming allocation after inducing a garbage collection.
static bool bAllocate = false;
// Variable for ending the example.
static bool finalExit = false;
// Collection for objects that
// simulate the server request workload.
static List<byte[]> load = new List<byte[]>();
public static void Main(string[] args)
{
try
{
// Register for a notification.
GC.RegisterForFullGCNotification(10, 10);
Console.WriteLine("Registered for GC notification.");
checkForNotify = true;
bAllocate = true;
// Start a thread using WaitForFullGCProc.
Thread thWaitForFullGC = new Thread(new ThreadStart(WaitForFullGCProc));
thWaitForFullGC.Start();
// While the thread is checking for notifications in
// WaitForFullGCProc, create objects to simulate a server workload.
try
{
int lastCollCount = 0;
int newCollCount = 0;
while (true)
{
if (bAllocate)
{
load.Add(new byte[1000]);
newCollCount = GC.CollectionCount(2);
if (newCollCount != lastCollCount)
{
// Show collection count when it increases:
Console.WriteLine("Gen 2 collection count: {0}", GC.CollectionCount(2).ToString());
lastCollCount = newCollCount;
}
// For ending the example (arbitrary).
if (newCollCount == 500)
{
finalExit = true;
checkForNotify = false;
break;
}
}
}
}
catch (OutOfMemoryException)
{
Console.WriteLine("Out of memory.");
}
finalExit = true;
checkForNotify = false;
GC.CancelFullGCNotification();
}
catch (InvalidOperationException invalidOp)
{
Console.WriteLine("GC Notifications are not supported while concurrent GC is enabled.\n"
+ invalidOp.Message);
}
}
public static void OnFullGCApproachNotify()
{
Console.WriteLine("Redirecting requests.");
// Method that tells the request queuing
// server to not direct requests to this server.
RedirectRequests();
// Method that provides time to
// finish processing pending requests.
FinishExistingRequests();
// This is a good time to induce a GC collection
// because the runtime will induce a full GC soon.
// To be very careful, you can check precede with a
// check of the GC.GCCollectionCount to make sure
// a full GC did not already occur since last notified.
GC.Collect();
Console.WriteLine("Induced a collection.");
}
public static void OnFullGCCompleteEndNotify()
{
// Method that informs the request queuing server
// that this server is ready to accept requests again.
AcceptRequests();
Console.WriteLine("Accepting requests again.");
}
public static void WaitForFullGCProc()
{
while (true)
{
// CheckForNotify is set to true and false in Main.
while (checkForNotify)
{
// Check for a notification of an approaching collection.
GCNotificationStatus s = GC.WaitForFullGCApproach();
if (s == GCNotificationStatus.Succeeded)
{
Console.WriteLine("GC Notification raised.");
OnFullGCApproachNotify();
}
else if (s == GCNotificationStatus.Canceled)
{
Console.WriteLine("GC Notification cancelled.");
break;
}
else
{
// This can occur if a timeout period
// is specified for WaitForFullGCApproach(Timeout)
// or WaitForFullGCComplete(Timeout)
// and the time out period has elapsed.
Console.WriteLine("GC Notification not applicable.");
break;
}
// Check for a notification of a completed collection.
GCNotificationStatus status = GC.WaitForFullGCComplete();
if (status == GCNotificationStatus.Succeeded)
{
Console.WriteLine("GC Notification raised.");
OnFullGCCompleteEndNotify();
}
else if (status == GCNotificationStatus.Canceled)
{
Console.WriteLine("GC Notification cancelled.");
break;
}
else
{
// Could be a time out.
Console.WriteLine("GC Notification not applicable.");
break;
}
}
Thread.Sleep(500);
// FinalExit is set to true right before
// the main thread cancelled notification.
if (finalExit)
{
break;
}
}
}
private static void RedirectRequests()
{
// Code that sends requests
// to other servers.
// Suspend work.
bAllocate = false;
}
private static void FinishExistingRequests()
{
// Code that waits a period of time
// for pending requests to finish.
// Clear the simulated workload.
load.Clear();
}
private static void AcceptRequests()
{
// Code that resumes processing
// requests on this server.
// Resume work.
bAllocate = true;
}
}
}
open System
open System.Threading
// Variable for continual checking in the
// While loop in the WaitForFullGCProc method.
let mutable checkForNotify = false
// Variable for suspending work
// (such servicing allocated server requests)
// after a notification is received and then
// resuming allocation after inducing a garbage collection.
let mutable bAllocate = false
// Variable for ending the example.
let mutable finalExit = false
// Collection for objects that simulate the server request workload.
let load = ResizeArray<byte []>()
let redirectRequests () =
// Code that sends requests
// to other servers.
// Suspend work.
bAllocate <- false
let finishExistingRequests () =
// Code that waits a period of time
// for pending requests to finish.
// Clear the simulated workload.
load.Clear()
let acceptRequests () =
// Code that resumes processing
// requests on this server.
// Resume work.
bAllocate <- true
let onFullGCApproachNotify () =
printfn "Redirecting requests."
// Method that tells the request queuing
// server to not direct requests to this server.
redirectRequests ()
// Method that provides time to
// finish processing pending requests.
finishExistingRequests ()
// This is a good time to induce a GC collection
// because the runtime will induce a full GC soon.
// To be very careful, you can check precede with a
// check of the GC.GCCollectionCount to make sure
// a full GC did not already occur since last notified.
GC.Collect()
printfn "Induced a collection."
let onFullGCCompleteEndNotify () =
// Method that informs the request queuing server
// that this server is ready to accept requests again.
acceptRequests ()
printfn "Accepting requests again."
let waitForFullGCProc () =
let mutable broken = false
while not broken do
let mutable broken = false
// CheckForNotify is set to true and false in Main.
while checkForNotify && not broken do
// Check for a notification of an approaching collection.
match GC.WaitForFullGCApproach() with
| GCNotificationStatus.Succeeded ->
printfn "GC Notification raised."
onFullGCApproachNotify ()
// Check for a notification of a completed collection.
match GC.WaitForFullGCComplete() with
| GCNotificationStatus.Succeeded ->
printfn "GC Notification raised."
onFullGCCompleteEndNotify ()
| GCNotificationStatus.Canceled ->
printfn "GC Notification cancelled."
broken <- true
| _ ->
// Could be a time out.
printfn "GC Notification not applicable."
broken <- true
| GCNotificationStatus.Canceled ->
printfn "GC Notification cancelled."
broken <- true
| _ ->
// This can occur if a timeout period
// is specified for WaitForFullGCApproach(Timeout)
// or WaitForFullGCComplete(Timeout)
// and the time out period has elapsed.
printfn "GC Notification not applicable."
broken <- true
Thread.Sleep 500
// FinalExit is set to true right before
// the main thread cancelled notification.
if finalExit then broken <- true
try
// Register for a notification.
GC.RegisterForFullGCNotification(10, 10)
printfn "Registered for GC notification."
checkForNotify <- true
bAllocate <- true
// Start a thread using WaitForFullGCProc.
let thWaitForFullGC = Thread(ThreadStart waitForFullGCProc)
thWaitForFullGC.Start()
// While the thread is checking for notifications in
// WaitForFullGCProc, create objects to simulate a server workload.
try
let mutable lastCollCount = 0
let mutable newCollCount = 0
let mutable broken = false
while not broken do
if bAllocate then
load.Add(Array.zeroCreate<byte> 1000)
newCollCount <- GC.CollectionCount 2
if newCollCount <> lastCollCount then
// Show collection count when it increases:
printfn $"Gen 2 collection count: {GC.CollectionCount(2)}"
lastCollCount <- newCollCount
// For ending the example (arbitrary).
if newCollCount = 500 then
finalExit <- true
checkForNotify <- false
broken <- true
with :? OutOfMemoryException -> printfn "Out of memory."
finalExit <- true
checkForNotify <- false
GC.CancelFullGCNotification()
with :? InvalidOperationException as invalidOp ->
printfn $"GC Notifications are not supported while concurrent GC is enabled.\n{invalidOp.Message}"
Imports System.Collections.Generic
Imports System.Threading
Class Program
' Variables for continual checking in the
' While loop in the WaitForFullGcProc method.
Private Shared checkForNotify As Boolean = False
' Variable for suspending work
' (such as servicing allocated server requests)
' after a notification is received and then
' resuming allocation after inducing a garbage collection.
Private Shared bAllocate As Boolean = False
' Variable for ending the example.
Private Shared finalExit As Boolean = False
' Collection for objects that
' simulate the server request workload.
Private Shared load As New List(Of Byte())
Public Shared Sub Main(ByVal args() As String)
Try
' Register for a notification.
GC.RegisterForFullGCNotification(10, 10)
Console.WriteLine("Registered for GC notification.")
bAllocate = True
checkForNotify = True
' Start a thread using WaitForFullGCProc.
Dim thWaitForFullGC As Thread = _
New Thread(New ThreadStart(AddressOf WaitForFullGCProc))
thWaitForFullGC.Start()
' While the thread is checking for notifications in
' WaitForFullGCProc, create objects to simulate a server workload.
Try
Dim lastCollCount As Integer = 0
Dim newCollCount As Integer = 0
While (True)
If bAllocate = True Then
load.Add(New Byte(1000) {})
newCollCount = GC.CollectionCount(2)
If (newCollCount <> lastCollCount) Then
' Show collection count when it increases:
Console.WriteLine("Gen 2 collection count: {0}", _
GC.CollectionCount(2).ToString)
lastCollCount = newCollCount
End If
' For ending the example (arbitrary).
If newCollCount = 500 Then
finalExit = True
checkForNotify = False
bAllocate = False
Exit While
End If
End If
End While
Catch outofMem As OutOfMemoryException
Console.WriteLine("Out of memory.")
End Try
finalExit = True
checkForNotify = False
GC.CancelFullGCNotification()
Catch invalidOp As InvalidOperationException
Console.WriteLine("GC Notifications are not supported while concurrent GC is enabled." _
& vbLf & invalidOp.Message)
End Try
End Sub
Public Shared Sub OnFullGCApproachNotify()
Console.WriteLine("Redirecting requests.")
' Method that tells the request queuing
' server to not direct requests to this server.
RedirectRequests()
' Method that provides time to
' finish processing pending requests.
FinishExistingRequests()
' This is a good time to induce a GC collection
' because the runtime will induce a ful GC soon.
' To be very careful, you can check precede with a
' check of the GC.GCCollectionCount to make sure
' a full GC did not already occur since last notified.
GC.Collect()
Console.WriteLine("Induced a collection.")
End Sub
Public Shared Sub OnFullGCCompleteEndNotify()
' Method that informs the request queuing server
' that this server is ready to accept requests again.
AcceptRequests()
Console.WriteLine("Accepting requests again.")
End Sub
Public Shared Sub WaitForFullGCProc()
While True
' CheckForNotify is set to true and false in Main.
While checkForNotify
' Check for a notification of an approaching collection.
Dim s As GCNotificationStatus = GC.WaitForFullGCApproach
If (s = GCNotificationStatus.Succeeded) Then
Console.WriteLine("GC Notification raised.")
OnFullGCApproachNotify()
ElseIf (s = GCNotificationStatus.Canceled) Then
Console.WriteLine("GC Notification cancelled.")
Exit While
Else
' This can occur if a timeout period
' is specified for WaitForFullGCApproach(Timeout)
' or WaitForFullGCComplete(Timeout)
' and the time out period has elapsed.
Console.WriteLine("GC Notification not applicable.")
Exit While
End If
' Check for a notification of a completed collection.
s = GC.WaitForFullGCComplete
If (s = GCNotificationStatus.Succeeded) Then
Console.WriteLine("GC Notifiction raised.")
OnFullGCCompleteEndNotify()
ElseIf (s = GCNotificationStatus.Canceled) Then
Console.WriteLine("GC Notification cancelled.")
Exit While
Else
' Could be a time out.
Console.WriteLine("GC Notification not applicable.")
Exit While
End If
End While
Thread.Sleep(500)
' FinalExit is set to true right before
' the main thread cancelled notification.
If finalExit Then
Exit While
End If
End While
End Sub
Private Shared Sub RedirectRequests()
' Code that sends requests
' to other servers.
' Suspend work.
bAllocate = False
End Sub
Private Shared Sub FinishExistingRequests()
' Code that waits a period of time
' for pending requests to finish.
' Clear the simulated workload.
load.Clear()
End Sub
Private Shared Sub AcceptRequests()
' Code that resumes processing
' requests on this server.
' Resume work.
bAllocate = True
End Sub
End Class
Comentarios
Para cada generación, el recolector de elementos no utilizados establece un umbral para las asignaciones en esa generación. Cuando el tamaño de las asignaciones supera este umbral, se desencadena una recolección de elementos no utilizados en esa generación. Por ejemplo, si el umbral de generación 2 es de 20 MB (lo que significa que 20 MB sobrevive a las recolecciones de generación 1 y se promueve a la generación 2), y más de 20 MB ha sobrevivido a la generación 1 y se le pide en la generación 2, se intentará la siguiente recolección de elementos no utilizados como una recolección de generación 2. Del mismo modo, si el umbral del montón de objetos grandes (LOH) es de 20 MB y la aplicación ha asignado más de 20 MB de objetos grandes, también se intentará la siguiente recolección de elementos no utilizados como una recolección de generación 2 (ya que el LOH solo se recopila en recolecciones de elementos no utilizados gen2).
Los maxGenerationThreshold umbrales y largeObjectHeapThreshold controlan la cantidad de antelación que se le notifica antes de que se produzca una recolección completa de elementos no utilizados. Cuanto mayor sea el umbral, más asignaciones pueden producirse entre la notificación y la siguiente recolección completa de elementos no utilizados.
Si tiene situaciones en las que una recolección completa de elementos no utilizados de Common Language Runtime afectaría negativamente al rendimiento de la aplicación, puede pedir que se le notifique cuando el tiempo de ejecución está a punto de realizar una recolección completa de elementos no utilizados y evitar esa recolección induciéndolo usted mismo (mediante el Collect método) cuando las condiciones siguen siendo favorables. Además de cambiar la programación de recolección de elementos no utilizados usted mismo, la notificación completa de GC es útil en los siguientes escenarios:
Supervisa el enfoque de una recolección de elementos no utilizados completa y, cuando se le notifica que se aproxima uno, se reduce el tamaño de los datos activos (por ejemplo, liberando algunas entradas de caché). Como resultado, cuando se produce la recolección de elementos no utilizados, es capaz de reclamar más memoria.
Supervisa la finalización de una recolección de elementos no utilizados completa para que pueda recopilar algunas estadísticas. Por ejemplo, es posible que desee medir el tamaño del montón en la finalización de GC para que sepa el tamaño de los datos activos. (Después de un GC completo, el montón tiene su tamaño más pequeño).
Para obtener más información sobre lo que representa una recolección de elementos no utilizados completa, consulte Notificaciones de recolección de elementos no utilizados.
Cuando se registra para recibir una notificación de recolección de elementos no utilizados, se puede recibir una notificación cuando se acerca una recolección completa de elementos no utilizados y cuando se completa. Este patrón es similar al modo en que el sistema operativo supervisa las notificaciones de memoria baja.
Use las instrucciones siguientes para especificar los maxGenerationThreshold parámetros y largeObjectHeapThreshold :
Cuanto mayor sea el valor de umbral, más asignaciones se producirán entre la notificación y la recolección completa de elementos no utilizados.
Un valor de umbral mayor proporciona más oportunidades para que el tiempo de ejecución compruebe si hay una recopilación que se aproxima. Esto aumenta la probabilidad de que se le notifique. Sin embargo, no debe establecer el umbral demasiado alto porque eso da lugar a más asignaciones antes de que el tiempo de ejecución induzca la siguiente colección.
Cuando se induce una colección después de la notificación mediante un valor de umbral alto, se reclaman menos objetos de los que la siguiente colección del entorno de ejecución reclamaría.
Cuanto menor sea el valor de umbral, menos asignaciones entre la notificación y la recolección completa de elementos no utilizados.
