< prev index next > src/jdk.management/share/classes/com/sun/management/internal/VirtualThreadSchedulerImpls.java
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* or visit www.oracle.com if you need additional information or have any
* questions.
*/
package com.sun.management.internal;
- import java.util.concurrent.Executor;
import java.util.concurrent.ForkJoinPool;
import javax.management.ObjectName;
import jdk.management.VirtualThreadSchedulerMXBean;
import jdk.internal.access.JavaLangAccess;
import jdk.internal.access.SharedSecrets;
import jdk.internal.vm.ContinuationSupport;
import sun.management.Util;
/**
! * Provides the implementation of the management interface for the JDK's default virtual
- * thread scheduler.
*/
public class VirtualThreadSchedulerImpls {
private VirtualThreadSchedulerImpls() {
}
public static VirtualThreadSchedulerMXBean create() {
! if (ContinuationSupport.isSupported()) {
! return new VirtualThreadSchedulerImpl();
- } else {
return new BoundVirtualThreadSchedulerImpl();
}
}
/**
* Base implementation of VirtualThreadSchedulerMXBean.
*/
* or visit www.oracle.com if you need additional information or have any
* questions.
*/
package com.sun.management.internal;
import java.util.concurrent.ForkJoinPool;
+ import java.util.concurrent.ThreadPoolExecutor;
import javax.management.ObjectName;
import jdk.management.VirtualThreadSchedulerMXBean;
import jdk.internal.access.JavaLangAccess;
import jdk.internal.access.SharedSecrets;
import jdk.internal.vm.ContinuationSupport;
import sun.management.Util;
/**
! * Provides the implementation of the management interface for the JDK's virtual thread scheduler.
*/
public class VirtualThreadSchedulerImpls {
+ private static final JavaLangAccess JLA = SharedSecrets.getJavaLangAccess();
+
private VirtualThreadSchedulerImpls() {
}
+ /**
+ * Creates the VirtualThreadSchedulerMXBean.
+ */
public static VirtualThreadSchedulerMXBean create() {
! // -XX:-VMContinuations
! if (!ContinuationSupport.isSupported()) {
return new BoundVirtualThreadSchedulerImpl();
}
+
+ // built-in scheduler
+ if (System.getProperty("jdk.virtualThreadScheduler.implClass") == null) {
+ return new BuiltinVirtualThreadSchedulerImpl();
+ }
+
+ // custom scheduler implements VirtualThreadSchedulerMXBean
+ if (JLA.defaultVirtualThreadScheduler() instanceof VirtualThreadSchedulerMXBean bean) {
+ return bean;
+ }
+
+ // custom scheduler does not implement VirtualThreadSchedulerMXBean
+ return new CustomVirtualThreadSchedulerImpl();
}
/**
* Base implementation of VirtualThreadSchedulerMXBean.
*/
}
}
/**
* Implementation of VirtualThreadSchedulerMXBean when virtual threads are
! * implemented with continuations + scheduler.
*/
! private static final class VirtualThreadSchedulerImpl extends BaseVirtualThreadSchedulerImpl {
! /**
! * Holder class for scheduler.
! */
! private static class Scheduler {
- private static final Executor scheduler =
- SharedSecrets.getJavaLangAccess().virtualThreadDefaultScheduler();
- static Executor instance() {
- return scheduler;
- }
}
@Override
public int getParallelism() {
! if (Scheduler.instance() instanceof ForkJoinPool pool) {
! return pool.getParallelism();
! }
! throw new InternalError(); // should not get here
}
@Override
public void setParallelism(int size) {
! if (Scheduler.instance() instanceof ForkJoinPool pool) {
pool.setParallelism(size);
! if (pool.getPoolSize() < size) {
! // FJ worker thread creation is on-demand
- Thread.startVirtualThread(() -> { });
- }
-
- return;
}
- throw new UnsupportedOperationException(); // should not get here
}
@Override
public int getPoolSize() {
! if (Scheduler.instance() instanceof ForkJoinPool pool) {
! return pool.getPoolSize();
! }
! return -1; // should not get here
}
@Override
public int getMountedVirtualThreadCount() {
! if (Scheduler.instance() instanceof ForkJoinPool pool) {
! return pool.getActiveThreadCount();
! }
! return -1; // should not get here
}
@Override
public long getQueuedVirtualThreadCount() {
! if (Scheduler.instance() instanceof ForkJoinPool pool) {
! return pool.getQueuedTaskCount() + pool.getQueuedSubmissionCount();
! }
! return -1L; // should not get here
}
}
/**
* Implementation of VirtualThreadSchedulerMXBean when virtual threads are backed
* by platform threads.
*/
! private static final class BoundVirtualThreadSchedulerImpl extends BaseVirtualThreadSchedulerImpl {
@Override
public int getParallelism() {
return Integer.MAX_VALUE;
}
}
}
/**
* Implementation of VirtualThreadSchedulerMXBean when virtual threads are
! * implemented with continuations and the built-in scheduler.
*/
! private static final class BuiltinVirtualThreadSchedulerImpl
! extends BaseVirtualThreadSchedulerImpl {
!
! private Thread.VirtualThreadScheduler builtinScheduler() {
! return JLA.builtinVirtualThreadScheduler();
}
@Override
public int getParallelism() {
! return switch (builtinScheduler()) {
! case ForkJoinPool pool -> pool.getParallelism();
! case ThreadPoolExecutor pool -> pool.getMaximumPoolSize();
! default -> -1;
+ };
}
@Override
public void setParallelism(int size) {
! if (builtinScheduler() instanceof ForkJoinPool pool) {
pool.setParallelism(size);
! } else {
! throw new UnsupportedOperationException();
}
}
@Override
public int getPoolSize() {
! return switch (builtinScheduler()) {
! case ForkJoinPool pool -> pool.getPoolSize();
! case ThreadPoolExecutor pool -> pool.getPoolSize();
! default -> -1;
+ };
}
@Override
public int getMountedVirtualThreadCount() {
! return switch (builtinScheduler()) {
! case ForkJoinPool pool -> pool.getActiveThreadCount();
! case ThreadPoolExecutor pool -> pool.getActiveCount();
! default -> -1;
+ };
}
@Override
public long getQueuedVirtualThreadCount() {
! return switch (builtinScheduler()) {
! case ForkJoinPool pool -> pool.getQueuedTaskCount() + pool.getQueuedSubmissionCount();
! case ThreadPoolExecutor pool -> pool.getQueue().size();
! default -> -1L;
+ };
}
}
/**
* Implementation of VirtualThreadSchedulerMXBean when virtual threads are backed
* by platform threads.
*/
! private static final class BoundVirtualThreadSchedulerImpl
+ extends BaseVirtualThreadSchedulerImpl {
@Override
public int getParallelism() {
return Integer.MAX_VALUE;
}
@Override
public long getQueuedVirtualThreadCount() {
return -1L;
}
}
+
+ /**
+ * Implementation of VirtualThreadSchedulerMXBean when using a custom virtual
+ * thread scheduler that does not implement VirtualThreadSchedulerMXBean.
+ */
+ private static final class CustomVirtualThreadSchedulerImpl
+ extends BaseVirtualThreadSchedulerImpl {
+
+ @Override
+ public int getParallelism() {
+ return 1;
+ }
+
+ @Override
+ public void setParallelism(int size) {
+ throw new UnsupportedOperationException();
+ }
+
+ @Override
+ public int getPoolSize() {
+ return -1;
+ }
+
+ @Override
+ public int getMountedVirtualThreadCount() {
+ return -1;
+ }
+
+ @Override
+ public long getQueuedVirtualThreadCount() {
+ return -1L;
+ }
+ }
}
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