6609775: Reduce context switches in DelayQueue due to signalAll
Reviewed-by: alanb
Contributed-by: Doug Lea <dl@cs.oswego.edu>
/*
* Copyright 2008 Sun Microsystems, Inc. All Rights Reserved.
* DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
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* under the terms of the GNU General Public License version 2 only, as
* published by the Free Software Foundation.
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* FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
* version 2 for more details (a copy is included in the LICENSE file that
* accompanied this code).
*
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* 2 along with this work; if not, write to the Free Software Foundation,
* Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
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*/
import java.util.concurrent.*;
import static java.util.concurrent.TimeUnit.*;
/**
* This is not a regression test, but a stress benchmark test for
* 6609775: Reduce context switches in DelayQueue due to signalAll
*
* This runs in the same wall clock time, but much reduced cpu time,
* with the changes for 6609775.
*/
public class Stress {
public static void main(String[] args) throws Throwable {
final DelayQueue<Delayed> q = new DelayQueue<Delayed>();
final long t0 = System.nanoTime();
for (long i = 0; i < 1000; i++) {
final long expiry = t0 + i*10L*1000L*1000L;
q.add(new Delayed() {
public long getDelay(TimeUnit unit) {
return unit.convert(expiry - System.nanoTime(),
NANOSECONDS);
}
public int compareTo(Delayed x) {
long d = getDelay(NANOSECONDS)
- x.getDelay(NANOSECONDS);
return d < 0 ? -1 : d > 0 ? 1 : 0; }});
}
for (int i = 0; i < 300; i++)
new Thread() { public void run() {
try {
while (!q.isEmpty())
q.poll(10L, TimeUnit.SECONDS);
} catch (Throwable t) { t.printStackTrace(); }
}}.start();
}
}