Bug 547014 - Improve executors for start-level and resolution
Change-Id: Idf2bf7e74394529f856a9b44e1040de0cce24805
Signed-off-by: Thomas Watson <tjwatson@us.ibm.com>
diff --git a/bundles/org.eclipse.osgi/container/src/org/eclipse/osgi/internal/framework/EquinoxContainerAdaptor.java b/bundles/org.eclipse.osgi/container/src/org/eclipse/osgi/internal/framework/EquinoxContainerAdaptor.java
index 7eb0eb3..248a8b6 100644
--- a/bundles/org.eclipse.osgi/container/src/org/eclipse/osgi/internal/framework/EquinoxContainerAdaptor.java
+++ b/bundles/org.eclipse.osgi/container/src/org/eclipse/osgi/internal/framework/EquinoxContainerAdaptor.java
@@ -22,6 +22,7 @@
import java.util.concurrent.Callable;
import java.util.concurrent.Executor;
import java.util.concurrent.ExecutorService;
+import java.util.concurrent.LinkedBlockingQueue;
import java.util.concurrent.RejectedExecutionHandler;
import java.util.concurrent.ScheduledExecutorService;
import java.util.concurrent.SynchronousQueue;
@@ -111,29 +112,31 @@
startLevelThreadCnt = 1;
}
- if ((resolverThreadCnt < 1 && startLevelThreadCnt < 1) || resolverThreadCnt == startLevelThreadCnt) {
- // use a single executor
- this.resolverExecutor = new AtomicLazyInitializer<>();
- this.lazyResolverExecutorCreator = createLazyExecutorCreator( //
- "Equinox executor thread - " + EquinoxContainerAdaptor.this.toString(), //$NON-NLS-1$
- resolverThreadCnt);
- this.startLevelExecutor = resolverExecutor;
- this.lazyStartLevelExecutorCreator = lazyResolverExecutorCreator;
- } else {
- // use two different executors
- this.resolverExecutor = new AtomicLazyInitializer<>();
- this.lazyResolverExecutorCreator = createLazyExecutorCreator( //
- "Equinox resolver thread - " + EquinoxContainerAdaptor.this.toString(), //$NON-NLS-1$
- resolverThreadCnt);
- this.startLevelExecutor = new AtomicLazyInitializer<>();
- this.lazyStartLevelExecutorCreator = createLazyExecutorCreator(//
- "Equinox start level thread - " + EquinoxContainerAdaptor.this.toString(), //$NON-NLS-1$
- startLevelThreadCnt);
- }
+ // Use two different executors for resolver and start-level because of the different queue requirements
+
+ // For the resolver we must use a SynchronousQueue because multiple threads
+ // can kick off a resolution operation and block one of the executor threads
+ // per resolution operation.
+ // If the number of concurrent resolution operations reaches the number of
+ // executor threads then each executor thread may end up blocked causing the
+ // executor to no longer accept work. A SynchronousQueue prevents that from
+ // happening.
+ this.resolverExecutor = new AtomicLazyInitializer<>();
+ this.lazyResolverExecutorCreator = createLazyExecutorCreator( //
+ "Equinox resolver thread - " + EquinoxContainerAdaptor.this.toString(), //$NON-NLS-1$
+ resolverThreadCnt, new SynchronousQueue<Runnable>());
+
+ // For the start-level we can safely use a growing queue because the thread feeding the
+ // start-level executor with work is a single thread and it can safely block waiting
+ // for the work of the executor threads to finish.
+ this.startLevelExecutor = new AtomicLazyInitializer<>();
+ this.lazyStartLevelExecutorCreator = createLazyExecutorCreator(//
+ "Equinox start level thread - " + EquinoxContainerAdaptor.this.toString(), //$NON-NLS-1$
+ startLevelThreadCnt, new LinkedBlockingQueue<Runnable>(1000));
}
- private Callable<Executor> createLazyExecutorCreator(final String threadName, int threadCnt) {
+ private Callable<Executor> createLazyExecutorCreator(final String threadName, int threadCnt, final BlockingQueue<Runnable> queue) {
// use the number of processors when configured value is <=0
final int maxThreads = threadCnt <= 0 ? Runtime.getRuntime().availableProcessors() : threadCnt;
return new Callable<Executor>() {
@@ -148,14 +151,10 @@
}
};
}
- // Decrement maxThreads by 1 for maxPoolSize because we use the current thread when max pool size is reached
- int maxPoolSize = maxThreads - 1;
- // Always want to go to zero threads when idle
- int coreThreads = 0;
+ // Always want to create core threads until max size
+ int coreThreads = maxThreads;
// idle timeout; make it short to get rid of threads quickly after use
int idleTimeout = 10;
- // use sync queue to force thread creation
- BlockingQueue<Runnable> queue = new SynchronousQueue<>();
// try to name the threads with useful name
ThreadFactory threadFactory = new ThreadFactory() {
@Override
@@ -166,13 +165,11 @@
}
};
// use a rejection policy that simply runs the task in the current thread once the max pool size is reached
- RejectedExecutionHandler rejectHandler = new RejectedExecutionHandler() {
- @Override
- public void rejectedExecution(Runnable r, ThreadPoolExecutor exe) {
- r.run();
- }
- };
- return new ThreadPoolExecutor(coreThreads, maxPoolSize, idleTimeout, TimeUnit.SECONDS, queue, threadFactory, rejectHandler);
+ RejectedExecutionHandler rejectHandler = new ThreadPoolExecutor.CallerRunsPolicy();
+
+ ThreadPoolExecutor executor = new ThreadPoolExecutor(coreThreads, maxThreads, idleTimeout, TimeUnit.SECONDS, queue, threadFactory, rejectHandler);
+ executor.allowCoreThreadTimeOut(true);
+ return executor;
}
};
}
