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8314515: java/util/concurrent/SynchronousQueue/Fairness.java failed with "Error: fair=false i=8 j=0"

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Backport-of: 35e9662767
This commit is contained in:
Elif Aslan
2024-06-21 02:42:59 +00:00
committed by Vitaly Provodin
parent 9a74b415ac
commit 4995f3ae2e
1 changed files with 35 additions and 7 deletions
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42
test/jdk/java/util/concurrent/SynchronousQueue/Fairness.java
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@@ -23,20 +23,45 @@
/*
* @test
* @modules java.base/java.util.concurrent:open
* @bug 4992438 6633113
* @summary Checks that fairness setting is respected.
*/
import java.lang.invoke.MethodHandles;
import java.lang.invoke.VarHandle;
import java.util.concurrent.BlockingQueue;
import java.util.concurrent.LinkedTransferQueue;
import java.util.concurrent.SynchronousQueue;
import java.util.concurrent.locks.Condition;
import java.util.concurrent.locks.ReentrantLock;
public class Fairness {
private static void testFairness(boolean fair,
final BlockingQueue<Integer> q)
private final static VarHandle underlyingTransferQueueAccess;
static {
try {
underlyingTransferQueueAccess =
MethodHandles.privateLookupIn(
SynchronousQueue.class,
MethodHandles.lookup()
).findVarHandle(
SynchronousQueue.class,
"transferer",
Class.forName(SynchronousQueue.class.getName() + "$Transferer")
);
} catch (Exception ex) {
throw new ExceptionInInitializerError(ex);
}
}
private static void testFairness(boolean fair, final SynchronousQueue<Integer> q)
throws Throwable
{
final LinkedTransferQueue<Integer> underlying =
(LinkedTransferQueue<Integer>)underlyingTransferQueueAccess.get(q);
final ReentrantLock lock = new ReentrantLock();
final Condition ready = lock.newCondition();
final int threadCount = 10;
@@ -53,9 +78,12 @@ public class Fairness {
} catch (Throwable t) { badness[0] = t; }}};
t.start();
ready.await();
// Probably unnecessary, but should be bullet-proof
while (t.getState() == Thread.State.RUNNABLE)
// Wait until previous put:ing thread is provably parked
while (underlying.size() < (i + 1))
Thread.yield();
if (underlying.size() > (i + 1))
throw new Error("Unexpected number of waiting producers: " + i);
}
for (int i = 0; i < threadCount; i++) {
int j = q.take();
@@ -68,8 +96,8 @@ public class Fairness {
}
public static void main(String[] args) throws Throwable {
testFairness(false, new SynchronousQueue<Integer>());
testFairness(false, new SynchronousQueue<Integer>(false));
testFairness(true, new SynchronousQueue<Integer>(true));
testFairness(false, new SynchronousQueue<>());
testFairness(false, new SynchronousQueue<>(false));
testFairness(true, new SynchronousQueue<>(true));
}
}