Bug 516609 - soft-limit number of job workers in worker pool
Change-Id: I9e5b4f027f13ce6358c7f7ee7a50fbb574b9276b
Signed-off-by: Igor Fedorenko <igor@ifedorenko.com>
Signed-off-by: Andrey Loskutov <loskutov@gmx.de>
diff --git a/bundles/org.eclipse.core.jobs/src/org/eclipse/core/internal/jobs/WorkerPool.java b/bundles/org.eclipse.core.jobs/src/org/eclipse/core/internal/jobs/WorkerPool.java
index ee38ffd..54716cf 100644
--- a/bundles/org.eclipse.core.jobs/src/org/eclipse/core/internal/jobs/WorkerPool.java
+++ b/bundles/org.eclipse.core.jobs/src/org/eclipse/core/internal/jobs/WorkerPool.java
@@ -7,6 +7,7 @@
*
* Contributors:
* IBM - Initial API and implementation
+ * salesforce.com - limit number of sleeping worker threads
*******************************************************************************/
package org.eclipse.core.internal.jobs;
@@ -33,6 +34,14 @@
* There will always be at least MIN_THREADS workers in the pool.
*/
private static final int MIN_THREADS = 1;
+
+ /**
+ * Soft limit on the maximum number of workers in the pool. An idle worker
+ * is not put back in the pool if the total number of workers is more than
+ * MAX_THREADS.
+ */
+ private static final int MAX_THREADS = 50;
+
/**
* Use the busy thread count to avoid starting new threads when a living
* thread is just doing house cleaning (notifying listeners, etc).
@@ -199,15 +208,17 @@
* Returns a new job to run. Returns null if the thread should die.
*/
protected InternalJob startJob(Worker worker) {
- //if we're above capacity, kill the thread
+ // must endWorker and decrementBusyThreads from the same synchronized block
+ boolean busy;
synchronized (this) {
if (!manager.isActive()) {
//must remove the worker immediately to prevent all threads from expiring
endWorker(worker);
return null;
}
- //set the thread to be busy now in case of reentrant scheduling
+ // set the thread to be busy now in case of reentrant scheduling
incrementBusyThreads();
+ busy = true;
}
Job job = null;
try {
@@ -216,8 +227,17 @@
long idleStart = System.currentTimeMillis();
while (manager.isActive() && job == null) {
long hint = manager.sleepHint();
- if (hint > 0)
+ if (hint > 0) {
+ synchronized (this) {
+ if (numThreads > MAX_THREADS) {
+ endWorker(worker);
+ decrementBusyThreads();
+ busy = false;
+ return null;
+ }
+ }
sleep(Math.min(hint, BEST_BEFORE));
+ }
job = manager.startJob(worker);
//if we were already idle, and there are still no new jobs, then
// the thread can expire
@@ -225,6 +245,8 @@
if (job == null && (System.currentTimeMillis() - idleStart > BEST_BEFORE) && (numThreads - busyThreads) > MIN_THREADS) {
//must remove the worker immediately to prevent all threads from expiring
endWorker(worker);
+ decrementBusyThreads();
+ busy = false;
return null;
}
}
@@ -245,7 +267,7 @@
}
} finally {
//decrement busy thread count if we're not running a job
- if (job == null)
+ if (job == null && busy)
decrementBusyThreads();
}
return job;
diff --git a/tests/org.eclipse.core.tests.runtime/src/org/eclipse/core/tests/runtime/jobs/AllTests.java b/tests/org.eclipse.core.tests.runtime/src/org/eclipse/core/tests/runtime/jobs/AllTests.java
index 22a1155..86010a3 100644
--- a/tests/org.eclipse.core.tests.runtime/src/org/eclipse/core/tests/runtime/jobs/AllTests.java
+++ b/tests/org.eclipse.core.tests.runtime/src/org/eclipse/core/tests/runtime/jobs/AllTests.java
@@ -45,6 +45,7 @@
suite.addTestSuite(Bug_316839.class);
suite.addTestSuite(Bug_320329.class);
suite.addTest(Bug_412138.suite());
+ suite.addTestSuite(WorkerPoolTest.class);
return suite;
}
}
diff --git a/tests/org.eclipse.core.tests.runtime/src/org/eclipse/core/tests/runtime/jobs/WorkerPoolTest.java b/tests/org.eclipse.core.tests.runtime/src/org/eclipse/core/tests/runtime/jobs/WorkerPoolTest.java
new file mode 100644
index 0000000..b7a54e8
--- /dev/null
+++ b/tests/org.eclipse.core.tests.runtime/src/org/eclipse/core/tests/runtime/jobs/WorkerPoolTest.java
@@ -0,0 +1,65 @@
+/*******************************************************************************
+ * Copyright (c) 2017 salesforce.com.
+ * All rights reserved. This program and the accompanying materials
+ * are made available under the terms of the Eclipse Public License v1.0
+ * which accompanies this distribution, and is available at
+ * http://www.eclipse.org/legal/epl-v10.html
+ *
+ * Contributors:
+ * salesforce.com - initial API and implementation
+ *******************************************************************************/
+package org.eclipse.core.tests.runtime.jobs;
+
+import java.util.concurrent.*;
+import junit.framework.TestCase;
+import org.eclipse.core.internal.jobs.Worker;
+import org.eclipse.core.runtime.*;
+import org.eclipse.core.runtime.jobs.Job;
+
+public class WorkerPoolTest extends TestCase {
+
+ public void testIdleWorkerCap() throws Exception {
+ // See org.eclipse.core.internal.jobs.WorkerPool.MAX_THREADS
+ final int MAX_THREADS = 50;
+
+ // number of concurrent jobs
+ final int count = MAX_THREADS * 10;
+
+ // cyclic barrier for count worker threads + one test thread
+ final CyclicBarrier barrier = new CyclicBarrier(count + 1);
+
+ // start count concurrent jobs
+ for (int i = 0; i < count; i++) {
+ new Job("testIdleWorkerCap-" + i) {
+ @Override
+ protected IStatus run(IProgressMonitor monitor) {
+ try {
+ barrier.await();
+ } catch (InterruptedException | BrokenBarrierException e) {
+ return Status.CANCEL_STATUS;
+ }
+ return Status.OK_STATUS;
+ }
+ }.schedule();
+ }
+
+ // wait for jobs to reach the barrier
+ barrier.await(10, TimeUnit.SECONDS);
+
+ // this is the ugly part, wait until worker threads become idle
+ Thread.sleep(5 * 1000L);
+
+ // count worker threads, must be less than WorkerPool.MAX_THREADS
+ Thread[] threads = new Thread[Thread.activeCount() * 2];
+ int tcount = Thread.enumerate(threads);
+ assertTrue("Too many active threads: " + tcount, tcount < threads.length);
+ int wcount = 0;
+ for (int i = 0; i < tcount; i++) {
+ if (threads[i] instanceof Worker) {
+ wcount++;
+ }
+ }
+ assertTrue("Too many worker threads active: " + wcount + ", must be <= " + MAX_THREADS, wcount <= MAX_THREADS);
+ }
+
+}
