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8160751: Optimize ConcurrentHashMap.keySet().removeAll

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8161372: ConcurrentHashMap.computeIfAbsent(k,f) locks bin when k present

Reviewed-by: martin, psandoz, plevart
This commit is contained in:
Doug Lea 2016-07-26 09:57:51 -07:00
parent 6db3f79f39
commit 825edd9274
2 changed files with 79 additions and 7 deletions
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41
jdk/src/java.base/share/classes/java/util/concurrent/ConcurrentHashMap.java
View File

@ -1023,7 +1023,7 @@ public class ConcurrentHashMap<K,V> extends AbstractMap<K,V>
int hash = spread(key.hashCode());
int binCount = 0;
for (Node<K,V>[] tab = table;;) {
Node<K,V> f; int n, i, fh;
Node<K,V> f; int n, i, fh; K fk; V fv;
if (tab == null || (n = tab.length) == 0)
tab = initTable();
else if ((f = tabAt(tab, i = (n - 1) & hash)) == null) {
@ -1032,6 +1032,10 @@ public class ConcurrentHashMap<K,V> extends AbstractMap<K,V>
}
else if ((fh = f.hash) == MOVED)
tab = helpTransfer(tab, f);
else if (onlyIfAbsent && fh == hash && // check first node
((fk = f.key) == key || fk != null && key.equals(fk)) &&
(fv = f.val) != null)
return fv;
else {
V oldVal = null;
synchronized (f) {
@ -1702,7 +1706,7 @@ public class ConcurrentHashMap<K,V> extends AbstractMap<K,V>
V val = null;
int binCount = 0;
for (Node<K,V>[] tab = table;;) {
Node<K,V> f; int n, i, fh;
Node<K,V> f; int n, i, fh; K fk; V fv;
if (tab == null || (n = tab.length) == 0)
tab = initTable();
else if ((f = tabAt(tab, i = (n - 1) & h)) == null) {
@ -1724,6 +1728,10 @@ public class ConcurrentHashMap<K,V> extends AbstractMap<K,V>
}
else if ((fh = f.hash) == MOVED)
tab = helpTransfer(tab, f);
else if (fh == h && // check first node
((fk = f.key) == key || fk != null && key.equals(fk)) &&
(fv = f.val) != null)
return fv;
else {
boolean added = false;
synchronized (f) {
@ -4553,14 +4561,21 @@ public class ConcurrentHashMap<K,V> extends AbstractMap<K,V>
return true;
}
public final boolean removeAll(Collection<?> c) {
public boolean removeAll(Collection<?> c) {
if (c == null) throw new NullPointerException();
boolean modified = false;
for (Iterator<E> it = iterator(); it.hasNext();) {
if (c.contains(it.next())) {
it.remove();
modified = true;
// Use (c instanceof Set) as a hint that lookup in c is as
// efficient as this view
if (c instanceof Set<?> && c.size() > map.table.length) {
for (Iterator<?> it = iterator(); it.hasNext(); ) {
if (c.contains(it.next())) {
it.remove();
modified = true;
}
}
} else {
for (Object e : c)
modified |= remove(e);
}
return modified;
}
@ -4747,6 +4762,18 @@ public class ConcurrentHashMap<K,V> extends AbstractMap<K,V>
throw new UnsupportedOperationException();
}
@Override public boolean removeAll(Collection<?> c) {
if (c == null) throw new NullPointerException();
boolean modified = false;
for (Iterator<V> it = iterator(); it.hasNext();) {
if (c.contains(it.next())) {
it.remove();
modified = true;
}
}
return modified;
}
public boolean removeIf(Predicate<? super V> filter) {
return map.removeValueIf(filter);
}

45
jdk/test/java/util/concurrent/tck/ConcurrentHashMapTest.java
View File

@ -43,6 +43,8 @@ import java.util.Map;
import java.util.Random;
import java.util.Set;
import java.util.concurrent.ConcurrentHashMap;
import java.util.concurrent.ExecutorService;
import java.util.concurrent.Executors;
import junit.framework.Test;
import junit.framework.TestSuite;
@ -830,4 +832,47 @@ public class ConcurrentHashMapTest extends JSR166TestCase {
}
}
/**
* Tests performance of removeAll when the other collection is much smaller.
* ant -Djsr166.tckTestClass=ConcurrentHashMapTest -Djsr166.methodFilter=testRemoveAll_performance -Djsr166.expensiveTests=true tck
*/
public void testRemoveAll_performance() {
final int mapSize = expensiveTests ? 1_000_000 : 100;
final int iterations = expensiveTests ? 500 : 2;
final ConcurrentHashMap<Integer, Integer> map = new ConcurrentHashMap<>();
for (int i = 0; i < mapSize; i++)
map.put(i, i);
Set<Integer> keySet = map.keySet();
Collection<Integer> removeMe = Arrays.asList(new Integer[] { -99, -86 });
for (int i = 0; i < iterations; i++)
assertFalse(keySet.removeAll(removeMe));
assertEquals(mapSize, map.size());
}
/**
* Tests performance of computeIfAbsent when the element is present.
* See JDK-8161372
* ant -Djsr166.tckTestClass=ConcurrentHashMapTest -Djsr166.methodFilter=testcomputeIfAbsent_performance -Djsr166.expensiveTests=true tck
*/
public void testcomputeIfAbsent_performance() {
final int mapSize = 20;
final int iterations = expensiveTests ? (1 << 23) : mapSize * 2;
final int threads = expensiveTests ? 10 : 2;
final ConcurrentHashMap<Integer, Integer> map = new ConcurrentHashMap<>();
for (int i = 0; i < mapSize; i++)
map.put(i, i);
final ExecutorService pool = Executors.newFixedThreadPool(2);
try (PoolCleaner cleaner = cleaner(pool)) {
Runnable r = new CheckedRunnable() {
public void realRun() {
int result = 0;
for (int i = 0; i < iterations; i++)
result += map.computeIfAbsent(i % mapSize, (k) -> k + k);
if (result == -42) throw new Error();
}};
for (int i = 0; i < threads; i++)
pool.execute(r);
}
}
}