GC.RegisterForFullGCNotification(Int32, Int32) Méthode
Définition
Important
Certaines informations portent sur la préversion du produit qui est susceptible d’être en grande partie modifiée avant sa publication. Microsoft exclut toute garantie, expresse ou implicite, concernant les informations fournies ici.
Spécifie qu’une notification de garbage collection doit être émise quand les conditions sont favorables à un garbage collection complet et quand celui-ci est terminé.
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)Paramètres
- maxGenerationThreshold
- Int32
Nombre entre 1 et 99 qui spécifie le moment auquel la notification doit être émise selon les objets alloués dans la génération 2.
- largeObjectHeapThreshold
- Int32
Nombre entre 1 et 99 qui spécifie le moment auquel la notification doit être émise selon les objets alloués dans le tas d'objets volumineux.
- Attributs
Exceptions
Ni maxGenerationThreshold ni largeObjectHeapThreshold n’est compris entre 1 et 99.
Ce membre n’est pas disponible quand le garbage collection simultané est activé. Pour plus d’informations sur la désactivation d’une opération garbage collection simultanée, consultez le paramètre d’exécution <gcConcurrent>.
Exemples
L’exemple suivant montre comment inscrire une notification de garbage collection et démarrer un thread pour surveiller l’état de la notification de garbage collection. Cet exemple de code fait partie d’un exemple plus grand fourni pour la rubrique Notifications de garbage collection .
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
Remarques
Pour chaque génération, le garbage collector définit un seuil pour les allocations dans cette génération. Lorsque la taille des allocations dépasse ce seuil, un garbage collection est déclenché sur cette génération. Par exemple, si le seuil de la génération 2 est de 20 Mo (ce qui signifie que 20 Mo survivent aux collections de génération 1 et est promu en génération 2), et que plus de 20 Mo ont survécu à la génération 1 et sont invités à la génération 2, le garbage collection suivant sera tenté en tant que collection de génération 2. De même, si le seuil du tas d’objets volumineux (LOH) est de 20 Mo et que votre application a alloué plus de 20 Mo d’objets volumineux, le garbage collection suivant sera également tenté en tant que collection de génération 2 (puisque le LOH n’est collecté que dans les garbage collections Gen2).
Les seuils et largeObjectHeapThreshold les maxGenerationThreshold seuils contrôlent la quantité à l’avance que vous êtes averti avant qu’un garbage collection complet ne se produise. Plus le seuil est élevé, plus les allocations peuvent se produire entre la notification et le garbage collection complet suivant.
Si vous avez des situations dans lesquelles un garbage collection complet par le Common Language Runtime affecterait négativement les performances de votre application, vous pouvez demander à être averti lorsque le runtime est sur le point d’effectuer un garbage collection complet et de contourner ce regroupement en inductant un regroupement vous-même (à l’aide de la Collect méthode) lorsque les conditions sont toujours favorables. En plus de modifier vous-même la planification du garbage collection, la notification GC complète est utile dans les scénarios suivants :
Vous surveillez l’approche d’un garbage collection complet et, lorsque vous êtes averti qu’un garbage collection approche, vous réduisez la taille des données actives (par exemple, en libérant certaines entrées de cache). Par conséquent, lorsque le garbage collection se produit, il est en mesure de récupérer plus de mémoire.
Vous surveillez l’achèvement d’un garbage collection complet afin de pouvoir collecter certaines statistiques. Par exemple, vous pouvez mesurer la taille du tas à l’achèvement du GC afin de connaître la taille des données actives. (Après un GC complet, le tas est à sa plus petite taille.)
Pour plus d’informations sur ce qui représente un garbage collection complet, consultez Notifications de garbage collection.
Lorsque vous vous inscrivez à une notification de garbage collection, vous pouvez être averti lorsqu’un garbage collection complet approche et quand il est terminé. Ce modèle ressemble à la façon dont le système d’exploitation surveille les notifications de mémoire insuffisante.
Utilisez les instructions suivantes pour spécifier les paramètres et largeObjectHeapThreshold les maxGenerationThreshold paramètres :
Plus la valeur de seuil est élevée, plus les allocations se produisent entre la notification et le garbage collection complet.
Une valeur de seuil supérieure offre davantage d’opportunités au runtime de vérifier une collection approche. Cela augmente la probabilité que vous soyez averti. Toutefois, vous ne devez pas définir le seuil trop élevé, car cela entraîne davantage d’allocations avant que le runtime n’entraîne la collection suivante.
Lorsque vous induire une collection vous-même lors d’une notification à l’aide d’une valeur de seuil élevé, moins d’objets sont récupérés que ce qui serait récupéré par la collection suivante du runtime.
Plus la valeur de seuil est réduite, moins les allocations entre la notification et le garbage collection complet sont réduites.