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Expose metrics for PooledByteBufAllocator

Browse Source 
Motivation:

The PooledByteBufAllocator is more or less a black-box atm. We need to expose some metrics to allow the user to get a better idea how to tune it.

Modifications:

- Expose different metrics via PooledByteBufAllocator
- Add *Metrics interfaces

Result:

It is now easy to gather metrics and detail about the PooledByteBufAllocator and so get a better understanding about resource-usage etc.
This commit is contained in:
Norman Maurer 2015-05-13 17:15:06 +02:00
parent 203ec13dd4
commit 6eac574b0e
13 changed files with 1231 additions and 28 deletions
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181
buffer/src/main/java/io/netty/buffer/PoolArena.java
View File

@ -16,12 +16,16 @@
package io.netty.buffer;
import io.netty.util.internal.LongCounter;
import io.netty.util.internal.PlatformDependent;
import io.netty.util.internal.StringUtil;
import java.nio.ByteBuffer;
import java.util.ArrayList;
import java.util.Collections;
import java.util.List;
abstract class PoolArena<T> {
abstract class PoolArena<T> implements PoolArenaMetric {
static final int numTinySubpagePools = 512 >>> 4;
@ -43,6 +47,21 @@ abstract class PoolArena<T> {
private final PoolChunkList<T> q075;
private final PoolChunkList<T> q100;
private final List<PoolChunkListMetric> chunkListMetrics;
// Metrics for allocations and deallocations
private long allocationsTiny;
private long allocationsSmall;
private long allocationsNormal;
// We need to use the LongCounter here as this is not guarded via synchronized block.
private final LongCounter allocationsHuge = PlatformDependent.newLongCounter();
private long deallocationsTiny;
private long deallocationsSmall;
private long deallocationsNormal;
// We need to use the LongCounter here as this is not guarded via synchronized block.
private final LongCounter deallocationsHuge = PlatformDependent.newLongCounter();
// TODO: Test if adding padding helps under contention
//private long pad0, pad1, pad2, pad3, pad4, pad5, pad6, pad7;
@ -77,6 +96,15 @@ abstract class PoolArena<T> {
q025.prevList = q000;
q000.prevList = null;
qInit.prevList = qInit;
List<PoolChunkListMetric> metrics = new ArrayList<PoolChunkListMetric>(6);
metrics.add(qInit);
metrics.add(q000);
metrics.add(q025);
metrics.add(q050);
metrics.add(q075);
metrics.add(q100);
chunkListMetrics = Collections.unmodifiableList(metrics);
}
private PoolSubpage<T> newSubpagePoolHead(int pageSize) {
@ -128,7 +156,8 @@ abstract class PoolArena<T> {
if (isTinyOrSmall(normCapacity)) { // capacity < pageSize
int tableIdx;
PoolSubpage<T>[] table;
if (isTiny(normCapacity)) { // < 512
boolean tiny = isTiny(normCapacity);
if (tiny) { // < 512
if (cache.allocateTiny(this, buf, reqCapacity, normCapacity)) {
// was able to allocate out of the cache so move on
return;
@ -152,6 +181,12 @@ abstract class PoolArena<T> {
long handle = s.allocate();
assert handle >= 0;
s.chunk.initBufWithSubpage(buf, handle, reqCapacity);
if (tiny) {
++allocationsTiny;
} else {
++allocationsSmall;
}
return;
}
allocateNormal(buf, reqCapacity, normCapacity);
@ -173,6 +208,8 @@ abstract class PoolArena<T> {
}
private void allocateNormal(PooledByteBuf<T> buf, int reqCapacity, int normCapacity) {
++allocationsNormal;
if (q050.allocate(buf, reqCapacity, normCapacity) || q025.allocate(buf, reqCapacity, normCapacity) ||
q000.allocate(buf, reqCapacity, normCapacity) || qInit.allocate(buf, reqCapacity, normCapacity) ||
q075.allocate(buf, reqCapacity, normCapacity) || q100.allocate(buf, reqCapacity, normCapacity)) {
@ -188,11 +225,13 @@ abstract class PoolArena<T> {
}
private void allocateHuge(PooledByteBuf<T> buf, int reqCapacity) {
allocationsHuge.increment();
buf.initUnpooled(newUnpooledChunk(reqCapacity), reqCapacity);
}
void free(PoolChunk<T> chunk, long handle, int normCapacity, boolean sameThreads) {
if (chunk.unpooled) {
allocationsHuge.decrement();
destroyChunk(chunk);
} else {
if (sameThreads) {
@ -203,7 +242,15 @@ abstract class PoolArena<T> {
}
}
boolean tinyOrSmall = isTinyOrSmall(normCapacity);
synchronized (this) {
if (!tinyOrSmall) {
++deallocationsNormal;
} else if (isTiny(normCapacity)) {
++deallocationsTiny;
} else {
++deallocationsSmall;
}
chunk.parent.free(chunk, handle);
}
}
@ -306,12 +353,142 @@ abstract class PoolArena<T> {
}
}
@Override
public int numTinySubpages() {
return tinySubpagePools.length;
}
@Override
public int numSmallSubpages() {
return smallSubpagePools.length;
}
@Override
public int numChunkLists() {
return chunkListMetrics.size();
}
@Override
public List<PoolSubpageMetric> tinySubpages() {
return subPageMetricList(tinySubpagePools);
}
@Override
public List<PoolSubpageMetric> smallSubpages() {
return subPageMetricList(smallSubpagePools);
}
@Override
public List<PoolChunkListMetric> chunkLists() {
return chunkListMetrics;
}
private static List<PoolSubpageMetric> subPageMetricList(PoolSubpage<?>[] pages) {
List<PoolSubpageMetric> metrics = new ArrayList<PoolSubpageMetric>();
for (int i = 1; i < pages.length; i ++) {
PoolSubpage<?> head = pages[i];
if (head.next == head) {
continue;
}
PoolSubpage<?> s = head.next;
for (;;) {
metrics.add(s);
s = s.next;
if (s == head) {
break;
}
}
}
return metrics;
}
@Override
public long numAllocations() {
return allocationsTiny + allocationsSmall + allocationsNormal + allocationsHuge.value();
}
@Override
public long numTinyAllocations() {
return allocationsTiny;
}
@Override
public long numSmallAllocations() {
return allocationsSmall;
}
@Override
public long numNormalAllocations() {
return allocationsNormal;
}
@Override
public long numDeallocations() {
return deallocationsTiny + deallocationsSmall + allocationsNormal + deallocationsHuge.value();
}
@Override
public long numTinyDeallocations() {
return deallocationsTiny;
}
@Override
public long numSmallDeallocations() {
return deallocationsSmall;
}
@Override
public long numNormalDeallocations() {
return deallocationsNormal;
}
@Override
public long numHugeAllocations() {
return allocationsHuge.value();
}
@Override
public long numHugeDeallocations() {
return deallocationsHuge.value();
}
@Override
public long numActiveAllocations() {
long val = numAllocations() - numDeallocations();
return val >= 0 ? val : 0;
}
@Override
public long numActiveTinyAllocations() {
long val = numTinyAllocations() - numTinyDeallocations();
return val >= 0 ? val : 0;
}
@Override
public long numActiveSmallAllocations() {
long val = numSmallAllocations() - numSmallDeallocations();
return val >= 0 ? val : 0;
}
@Override
public long numActiveNormalAllocations() {
long val = numNormalAllocations() - numNormalDeallocations();
return val >= 0 ? val : 0;
}
@Override
public long numActiveHugeAllocations() {
long val = numHugeAllocations() - numHugeDeallocations();
return val >= 0 ? val : 0;
}
protected abstract PoolChunk<T> newChunk(int pageSize, int maxOrder, int pageShifts, int chunkSize);
protected abstract PoolChunk<T> newUnpooledChunk(int capacity);
protected abstract PooledByteBuf<T> newByteBuf(int maxCapacity);
protected abstract void memoryCopy(T src, int srcOffset, T dst, int dstOffset, int length);
protected abstract void destroyChunk(PoolChunk<T> chunk);
@Override
public synchronized String toString() {
StringBuilder buf = new StringBuilder()
.append("Chunk(s) at 0~25%:")

130
buffer/src/main/java/io/netty/buffer/PoolArenaMetric.java Normal file
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@ -0,0 +1,130 @@
/*
* Copyright 2015 The Netty Project
*
* The Netty Project licenses this file to you under the Apache License,
* version 2.0 (the "License"); you may not use this file except in compliance
* with the License. You may obtain a copy of the License at:
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
* WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
* License for the specific language governing permissions and limitations
* under the License.
*/
package io.netty.buffer;
import java.util.List;
/**
* Expose metrics for an arena.
*/
public interface PoolArenaMetric {
/**
* Returns the number of tiny sub-pages for the arena.
*/
int numTinySubpages();
/**
* Returns the number of small sub-pages for the arena.
*/
int numSmallSubpages();
/**
* Returns the number of chunk lists for the arena.
*/
int numChunkLists();
/**
* Returns an unmodifiable {@link List} which holds {@link PoolSubpageMetric}s for tiny sub-pages.
*/
List<PoolSubpageMetric> tinySubpages();
/**
* Returns an unmodifiable {@link List} which holds {@link PoolSubpageMetric}s for small sub-pages.
*/
List<PoolSubpageMetric> smallSubpages();
/**
* Returns an unmodifiable {@link List} which holds {@link PoolChunkListMetric}s.
*/
List<PoolChunkListMetric> chunkLists();
/**
* Return the number of allocations done via the arena. This includes all sizes.
*/
long numAllocations();
/**
* Return the number of tiny allocations done via the arena.
*/
long numTinyAllocations();
/**
* Return the number of small allocations done via the arena.
*/
long numSmallAllocations();
/**
* Return the number of normal allocations done via the arena.
*/
long numNormalAllocations();
/**
* Return the number of huge allocations done via the arena.
*/
long numHugeAllocations();
/**
* Return the number of deallocations done via the arena. This includes all sizes.
*/
long numDeallocations();
/**
* Return the number of tiny deallocations done via the arena.
*/
long numTinyDeallocations();
/**
* Return the number of small deallocations done via the arena.
*/
long numSmallDeallocations();
/**
* Return the number of normal deallocations done via the arena.
*/
long numNormalDeallocations();
/**
* Return the number of huge deallocations done via the arena.
*/
long numHugeDeallocations();
/**
* Return the number of currently active allocations.
*/
long numActiveAllocations();
/**
* Return the number of currently active tiny allocations.
*/
long numActiveTinyAllocations();
/**
* Return the number of currently active small allocations.
*/
long numActiveSmallAllocations();
/**
* Return the number of currently active normal allocations.
*/
long numActiveNormalAllocations();
/**
* Return the number of currently active huge allocations.
*/
long numActiveHugeAllocations();
}

16
buffer/src/main/java/io/netty/buffer/PoolChunk.java
View File

@ -100,8 +100,7 @@ package io.netty.buffer;
* where as per convention defined above
* the second value (i.e, x) indicates that the first node which is free to be allocated is at depth x (from root)
*/
final class PoolChunk<T> {
final class PoolChunk<T> implements PoolChunkMetric {
final PoolArena<T> arena;
final T memory;
@ -186,7 +185,8 @@ final class PoolChunk<T> {
return new PoolSubpage[size];
}
int usage() {
@Override
public int usage() {
final int freeBytes = this.freeBytes;
if (freeBytes == 0) {
return 100;
@ -414,6 +414,16 @@ final class PoolChunk<T> {
return memoryMapIdx ^ maxSubpageAllocs; // remove highest set bit, to get offset
}
@Override
public int chunkSize() {
return chunkSize;
}
@Override
public int freeBytes() {
return freeBytes;
}
@Override
public String toString() {
return new StringBuilder()

34
buffer/src/main/java/io/netty/buffer/PoolChunkList.java
View File

@ -18,7 +18,13 @@ package io.netty.buffer;
import io.netty.util.internal.StringUtil;
final class PoolChunkList<T> {
import java.util.ArrayList;
import java.util.Collections;
import java.util.Iterator;
import java.util.List;
final class PoolChunkList<T> implements PoolChunkListMetric {
private static final Iterator<PoolChunkMetric> EMPTY_METRICS = Collections.<PoolChunkMetric>emptyList().iterator();
private final PoolArena<T> arena;
private final PoolChunkList<T> nextList;
PoolChunkList<T> prevList;
@ -108,6 +114,32 @@ final class PoolChunkList<T> {
}
}
@Override
public int minUsage() {
return minUsage;
}
@Override
public int maxUsage() {
return maxUsage;
}
@Override
public Iterator<PoolChunkMetric> iterator() {
if (head == null) {
return EMPTY_METRICS;
}
List<PoolChunkMetric> metrics = new ArrayList<PoolChunkMetric>();
for (PoolChunk<T> cur = head;;) {
metrics.add(cur);
cur = cur.next;
if (cur == null) {
break;
}
}
return metrics.iterator();
}
@Override
public String toString() {
if (head == null) {

32
buffer/src/main/java/io/netty/buffer/PoolChunkListMetric.java Normal file
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@ -0,0 +1,32 @@
/*
* Copyright 2015 The Netty Project
*
* The Netty Project licenses this file to you under the Apache License,
* version 2.0 (the "License"); you may not use this file except in compliance
* with the License. You may obtain a copy of the License at:
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
* WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
* License for the specific language governing permissions and limitations
* under the License.
*/
package io.netty.buffer;
/**
* Metrics for a list of chunks.
*/
public interface PoolChunkListMetric extends Iterable<PoolChunkMetric> {
/**
* Return the minum usage of the chunk list before which chunks are promoted to the previous list.
*/
int minUsage();
/**
* Return the minum usage of the chunk list after which chunks are promoted to the next list.
*/
int maxUsage();
}

37
buffer/src/main/java/io/netty/buffer/PoolChunkMetric.java Normal file
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@ -0,0 +1,37 @@
/*
* Copyright 2015 The Netty Project
*
* The Netty Project licenses this file to you under the Apache License,
* version 2.0 (the "License"); you may not use this file except in compliance
* with the License. You may obtain a copy of the License at:
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
* WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
* License for the specific language governing permissions and limitations
* under the License.
*/
package io.netty.buffer;
/**
* Metrics for a chunk.
*/
public interface PoolChunkMetric {
/**
* Return the percentage of the current usage of the chunk.
*/
int usage();
/**
* Return the size of the chunk in bytes, this is the maximum of bytes that can be served out of the chunk.
*/
int chunkSize();
/**
* Return the number of free bytes in the chunk.
*/
int freeBytes();
}

23
buffer/src/main/java/io/netty/buffer/PoolSubpage.java
View File

@ -16,7 +16,7 @@
package io.netty.buffer;
final class PoolSubpage<T> {
final class PoolSubpage<T> implements PoolSubpageMetric {
final PoolChunk<T> chunk;
private final int memoryMapIdx;
@ -202,6 +202,7 @@ final class PoolSubpage<T> {
return 0x4000000000000000L | (long) bitmapIdx << 32 | memoryMapIdx;
}
@Override
public String toString() {
if (!doNotDestroy) {
return "(" + memoryMapIdx + ": not in use)";
@ -210,4 +211,24 @@ final class PoolSubpage<T> {
return String.valueOf('(') + memoryMapIdx + ": " + (maxNumElems - numAvail) + '/' + maxNumElems +
", offset: " + runOffset + ", length: " + pageSize + ", elemSize: " + elemSize + ')';
}
@Override
public int maxNumElements() {
return maxNumElems;
}
@Override
public int numAvailable() {
return numAvail;
}
@Override
public int elementSize() {
return elemSize;
}
@Override
public int pageSize() {
return pageSize;
}
}

43
buffer/src/main/java/io/netty/buffer/PoolSubpageMetric.java Normal file
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@ -0,0 +1,43 @@
/*
* Copyright 2015 The Netty Project
*
* The Netty Project licenses this file to you under the Apache License,
* version 2.0 (the "License"); you may not use this file except in compliance
* with the License. You may obtain a copy of the License at:
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
* WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
* License for the specific language governing permissions and limitations
* under the License.
*/
package io.netty.buffer;
/**
* Metrics for a sub-page.
*/
public interface PoolSubpageMetric {
/**
* Return the number of maximal elements that can be allocated out of the sub-page.
*/
int maxNumElements();
/**
* Return the number of available elements to be allocated.
*/
int numAvailable();
/**
* Return the size (in bytes) of the elements that will be allocated.
*/
int elementSize();
/**
* Return the size (in bytes) of this page.
*/
int pageSize();
}

126
buffer/src/main/java/io/netty/buffer/PooledByteBufAllocator.java
View File

@ -23,6 +23,9 @@ import io.netty.util.internal.logging.InternalLogger;
import io.netty.util.internal.logging.InternalLoggerFactory;
import java.nio.ByteBuffer;
import java.util.ArrayList;
import java.util.Collections;
import java.util.List;
import java.util.concurrent.atomic.AtomicInteger;
public class PooledByteBufAllocator extends AbstractByteBufAllocator {
@ -125,6 +128,9 @@ public class PooledByteBufAllocator extends AbstractByteBufAllocator {
private final int smallCacheSize;
private final int normalCacheSize;
private final List<PoolArenaMetric> heapArenaMetrics;
private final List<PoolArenaMetric> directArenaMetrics;
final PoolThreadLocalCache threadCache;
public PooledByteBufAllocator() {
@ -164,20 +170,31 @@ public class PooledByteBufAllocator extends AbstractByteBufAllocator {
if (nHeapArena > 0) {
heapArenas = newArenaArray(nHeapArena);
List<PoolArenaMetric> metrics = new ArrayList<PoolArenaMetric>(heapArenas.length);
for (int i = 0; i < heapArenas.length; i ++) {
heapArenas[i] = new PoolArena.HeapArena(this, pageSize, maxOrder, pageShifts, chunkSize);
PoolArena.HeapArena arena = new PoolArena.HeapArena(this, pageSize, maxOrder, pageShifts, chunkSize);
heapArenas[i] = arena;
metrics.add(arena);
}
heapArenaMetrics = Collections.unmodifiableList(metrics);
} else {
heapArenas = null;
heapArenaMetrics = Collections.emptyList();
}
if (nDirectArena > 0) {
directArenas = newArenaArray(nDirectArena);
List<PoolArenaMetric> metrics = new ArrayList<PoolArenaMetric>(directArenas.length);
for (int i = 0; i < directArenas.length; i ++) {
directArenas[i] = new PoolArena.DirectArena(this, pageSize, maxOrder, pageShifts, chunkSize);
PoolArena.DirectArena arena = new PoolArena.DirectArena(
this, pageSize, maxOrder, pageShifts, chunkSize);
directArenas[i] = arena;
metrics.add(arena);
}
directArenaMetrics = Collections.unmodifiableList(metrics);
} else {
directArenas = null;
directArenaMetrics = Collections.emptyList();
}
}
@ -257,9 +274,11 @@ public class PooledByteBufAllocator extends AbstractByteBufAllocator {
final class PoolThreadLocalCache extends FastThreadLocal<PoolThreadCache> {
private final AtomicInteger index = new AtomicInteger();
final AtomicInteger caches = new AtomicInteger();
@Override
protected PoolThreadCache initialValue() {
caches.incrementAndGet();
final int idx = index.getAndIncrement();
final PoolArena<byte[]> heapArena;
final PoolArena<ByteBuffer> directArena;
@ -275,7 +294,6 @@ public class PooledByteBufAllocator extends AbstractByteBufAllocator {
} else {
directArena = null;
}
return new PoolThreadCache(
heapArena, directArena, tinyCacheSize, smallCacheSize, normalCacheSize,
DEFAULT_MAX_CACHED_BUFFER_CAPACITY, DEFAULT_CACHE_TRIM_INTERVAL);
@ -284,25 +302,91 @@ public class PooledByteBufAllocator extends AbstractByteBufAllocator {
@Override
protected void onRemoval(PoolThreadCache value) {
value.free();
caches.decrementAndGet();
}
}
// Too noisy at the moment.
//
// public String toString() {
// StringBuilder buf = new StringBuilder();
// buf.append(heapArenas.length);
// buf.append(" heap arena(s):");
// buf.append(StringUtil.NEWLINE);
// for (PoolArena<byte[]> a: heapArenas) {
// buf.append(a);
// }
// buf.append(directArenas.length);
// buf.append(" direct arena(s):");
// buf.append(StringUtil.NEWLINE);
// for (PoolArena<ByteBuffer> a: directArenas) {
// buf.append(a);
// }
// return buf.toString();
// }
/**
* Return the number of heap arenas.
*/
public int numHeapArenas() {
return heapArenaMetrics.size();
}
/**
* Return the number of direct arenas.
*/
public int numDirectArenas() {
return directArenaMetrics.size();
}
/**
* Return a {@link List} of all heap {@link PoolArenaMetric}s that are provided by this pool.
*/
public List<PoolArenaMetric> heapArenas() {
return heapArenaMetrics;
}
/**
* Return a {@link List} of all direct {@link PoolArenaMetric}s that are provided by this pool.
*/
public List<PoolArenaMetric> directArenas() {
return directArenaMetrics;
}
/**
* Return the number of thread local caches used by this {@link PooledByteBufAllocator}.
*/
public int numThreadLocalCaches() {
return threadCache.caches.get();
}
/**
* Return the size of the tiny cache.
*/
public int tinyCacheSize() {
return tinyCacheSize;
}
/**
* Return the size of the small cache.
*/
public int smallCacheSize() {
return smallCacheSize;
}
/**
* Return the size of the normal cache.
*/
public int normalCacheSize() {
return normalCacheSize;
}
// Too noisy at the moment.
//
//public String toString() {
// StringBuilder buf = new StringBuilder();
// int heapArenasLen = heapArenas == null ? 0 : heapArenas.length;
// buf.append(heapArenasLen);
// buf.append(" heap arena(s):");
// buf.append(StringUtil.NEWLINE);
// if (heapArenasLen > 0) {
// for (PoolArena<byte[]> a: heapArenas) {
// buf.append(a);
// }
// }
//
// int directArenasLen = directArenas == null ? 0 : directArenas.length;
//
// buf.append(directArenasLen);
// buf.append(" direct arena(s):");
// buf.append(StringUtil.NEWLINE);
// if (directArenasLen > 0) {
// for (PoolArena<ByteBuffer> a: directArenas) {
// buf.append(a);
// }
// }
//
// return buf.toString();
//}
}

26
common/src/main/java/io/netty/util/internal/LongCounter.java Normal file
View File

@ -0,0 +1,26 @@
/*
* Copyright 2015 The Netty Project
*
* The Netty Project licenses this file to you under the Apache License,
* version 2.0 (the "License"); you may not use this file except in compliance
* with the License. You may obtain a copy of the License at:
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
* WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
* License for the specific language governing permissions and limitations
* under the License.
*/
package io.netty.util.internal;
/**
* Counter for long.
*/
public interface LongCounter {
void add(long delta);
void increment();
void decrement();
long value();
}

35
common/src/main/java/io/netty/util/internal/PlatformDependent.java
View File

@ -17,6 +17,7 @@ package io.netty.util.internal;
import io.netty.util.CharsetUtil;
import io.netty.util.internal.chmv8.ConcurrentHashMapV8;
import io.netty.util.internal.chmv8.LongAdderV8;
import io.netty.util.internal.logging.InternalLogger;
import io.netty.util.internal.logging.InternalLoggerFactory;
@ -40,6 +41,7 @@ import java.util.concurrent.ConcurrentLinkedDeque;
import java.util.concurrent.ConcurrentMap;
import java.util.concurrent.LinkedBlockingDeque;
import java.util.concurrent.atomic.AtomicIntegerFieldUpdater;
import java.util.concurrent.atomic.AtomicLong;
import java.util.concurrent.atomic.AtomicLongFieldUpdater;
import java.util.concurrent.atomic.AtomicReferenceFieldUpdater;
import java.util.regex.Matcher;
@ -227,6 +229,17 @@ public final class PlatformDependent {
}
}
/**
* Creates a new fastest {@link LongCounter} implementaion for the current platform.
*/
public static LongCounter newLongCounter() {
if (HAS_UNSAFE) {
return new LongAdderV8();
} else {
return new AtomicLongCounter();
}
}
/**
* Creates a new fastest {@link ConcurrentMap} implementaion for the current platform.
*/
@ -886,6 +899,28 @@ public final class PlatformDependent {
return true;
}
private static final class AtomicLongCounter extends AtomicLong implements LongCounter {
@Override
public void add(long delta) {
addAndGet(delta);
}
@Override
public void increment() {
incrementAndGet();
}
@Override
public void decrement() {
decrementAndGet();
}
@Override
public long value() {
return get();
}
}
private PlatformDependent() {
// only static method supported
}

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/*
* Copyright 2015 The Netty Project
*
* The Netty Project licenses this file to you under the Apache License,
* version 2.0 (the "License"); you may not use this file except in compliance
* with the License. You may obtain a copy of the License at:
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
* WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
* License for the specific language governing permissions and limitations
* under the License.
*/
/*
* Written by Doug Lea with assistance from members of JCP JSR-166
* Expert Group and released to the public domain, as explained at
* http://creativecommons.org/publicdomain/zero/1.0/
*/
package io.netty.util.internal.chmv8;
import io.netty.util.internal.LongCounter;
import java.io.IOException;
import java.io.ObjectInputStream;
import java.io.ObjectOutputStream;
import java.io.Serializable;
import java.util.concurrent.atomic.AtomicLong;
/**
* One or more variables that together maintain an initially zero
* {@code long} sum. When updates (method {@link #add}) are contended
* across threads, the set of variables may grow dynamically to reduce
* contention. Method {@link #sum} (or, equivalently, {@link
* #longValue}) returns the current total combined across the
* variables maintaining the sum.
*
* <p>This class is usually preferable to {@link AtomicLong} when
* multiple threads update a common sum that is used for purposes such
* as collecting statistics, not for fine-grained synchronization
* control. Under low update contention, the two classes have similar
* characteristics. But under high contention, expected throughput of
* this class is significantly higher, at the expense of higher space
* consumption.
*
* <p>This class extends {@link Number}, but does <em>not</em> define
* methods such as {@code equals}, {@code hashCode} and {@code
* compareTo} because instances are expected to be mutated, and so are
* not useful as collection keys.
*
* <p><em>jsr166e note: This class is targeted to be placed in
* java.util.concurrent.atomic.</em>
*
* @since 1.8
* @author Doug Lea
*/
@SuppressWarnings("all")
public class LongAdderV8 extends Striped64 implements Serializable, LongCounter {
private static final long serialVersionUID = 7249069246863182397L;
/**
* Version of plus for use in retryUpdate
*/
final long fn(long v, long x) { return v + x; }
/**
* Creates a new adder with initial sum of zero.
*/
public LongAdderV8() {
}
/**
* Adds the given value.
*
* @param x the value to add
*/
public void add(long x) {
Cell[] as; long b, v; int[] hc; Cell a; int n;
if ((as = cells) != null || !casBase(b = base, b + x)) {
boolean uncontended = true;
if ((hc = threadHashCode.get()) == null ||
as == null || (n = as.length) < 1 ||
(a = as[(n - 1) & hc[0]]) == null ||
!(uncontended = a.cas(v = a.value, v + x)))
retryUpdate(x, hc, uncontended);
}
}
/**
* Equivalent to {@code add(1)}.
*/
public void increment() {
add(1L);
}
/**
* Equivalent to {@code add(-1)}.
*/
public void decrement() {
add(-1L);
}
/**
* Returns the current sum. The returned value is <em>NOT</em> an
* atomic snapshot; invocation in the absence of concurrent
* updates returns an accurate result, but concurrent updates that
* occur while the sum is being calculated might not be
* incorporated.
*
* @return the sum
*/
public long sum() {
long sum = base;
Cell[] as = cells;
if (as != null) {
int n = as.length;
for (int i = 0; i < n; ++i) {
Cell a = as[i];
if (a != null)
sum += a.value;
}
}
return sum;
}
/**
* Resets variables maintaining the sum to zero. This method may
* be a useful alternative to creating a new adder, but is only
* effective if there are no concurrent updates. Because this
* method is intrinsically racy, it should only be used when it is
* known that no threads are concurrently updating.
*/
public void reset() {
internalReset(0L);
}
/**
* Equivalent in effect to {@link #sum} followed by {@link
* #reset}. This method may apply for example during quiescent
* points between multithreaded computations. If there are
* updates concurrent with this method, the returned value is
* <em>not</em> guaranteed to be the final value occurring before
* the reset.
*
* @return the sum
*/
public long sumThenReset() {
long sum = base;
Cell[] as = cells;
base = 0L;
if (as != null) {
int n = as.length;
for (int i = 0; i < n; ++i) {
Cell a = as[i];
if (a != null) {
sum += a.value;
a.value = 0L;
}
}
}
return sum;
}
/**
* Returns the String representation of the {@link #sum}.
* @return the String representation of the {@link #sum}
*/
public String toString() {
return Long.toString(sum());
}
/**
* Equivalent to {@link #sum}.
*
* @return the sum
*/
public long longValue() {
return sum();
}
/**
* Returns the {@link #sum} as an {@code int} after a narrowing
* primitive conversion.
*/
public int intValue() {
return (int)sum();
}
/**
* Returns the {@link #sum} as a {@code float}
* after a widening primitive conversion.
*/
public float floatValue() {
return (float)sum();
}
/**
* Returns the {@link #sum} as a {@code double} after a widening
* primitive conversion.
*/
public double doubleValue() {
return (double)sum();
}
private void writeObject(ObjectOutputStream s) throws IOException {
s.defaultWriteObject();
s.writeLong(sum());
}
private void readObject(ObjectInputStream s)
throws IOException, ClassNotFoundException {
s.defaultReadObject();
busy = 0;
cells = null;
base = s.readLong();
}
@Override
public long value() {
return sum();
}
}

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/*
* Copyright 2015 The Netty Project
*
* The Netty Project licenses this file to you under the Apache License,
* version 2.0 (the "License"); you may not use this file except in compliance
* with the License. You may obtain a copy of the License at:
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
* WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
* License for the specific language governing permissions and limitations
* under the License.
*/
/*
* Written by Doug Lea with assistance from members of JCP JSR-166
* Expert Group and released to the public domain, as explained at
* http://creativecommons.org/publicdomain/zero/1.0/
*/
package io.netty.util.internal.chmv8;
import java.util.Random;
/**
* A package-local class holding common representation and mechanics
* for classes supporting dynamic striping on 64bit values. The class
* extends Number so that concrete subclasses must publicly do so.
*/
@SuppressWarnings("all")
abstract class Striped64 extends Number {
/*
* This class maintains a lazily-initialized table of atomically
* updated variables, plus an extra "base" field. The table size
* is a power of two. Indexing uses masked per-thread hash codes.
* Nearly all declarations in this class are package-private,
* accessed directly by subclasses.
*
* Table entries are of class Cell; a variant of AtomicLong padded
* to reduce cache contention on most processors. Padding is
* overkill for most Atomics because they are usually irregularly
* scattered in memory and thus don't interfere much with each
* other. But Atomic objects residing in arrays will tend to be
* placed adjacent to each other, and so will most often share
* cache lines (with a huge negative performance impact) without
* this precaution.
*
* In part because Cells are relatively large, we avoid creating
* them until they are needed. When there is no contention, all
* updates are made to the base field. Upon first contention (a
* failed CAS on base update), the table is initialized to size 2.
* The table size is doubled upon further contention until
* reaching the nearest power of two greater than or equal to the
* number of CPUS. Table slots remain empty (null) until they are
* needed.
*
* A single spinlock ("busy") is used for initializing and
* resizing the table, as well as populating slots with new Cells.
* There is no need for a blocking lock; when the lock is not
* available, threads try other slots (or the base). During these
* retries, there is increased contention and reduced locality,
* which is still better than alternatives.
*
* Per-thread hash codes are initialized to random values.
* Contention and/or table collisions are indicated by failed
* CASes when performing an update operation (see method
* retryUpdate). Upon a collision, if the table size is less than
* the capacity, it is doubled in size unless some other thread
* holds the lock. If a hashed slot is empty, and lock is
* available, a new Cell is created. Otherwise, if the slot
* exists, a CAS is tried. Retries proceed by "double hashing",
* using a secondary hash (Marsaglia XorShift) to try to find a
* free slot.
*
* The table size is capped because, when there are more threads
* than CPUs, supposing that each thread were bound to a CPU,
* there would exist a perfect hash function mapping threads to
* slots that eliminates collisions. When we reach capacity, we
* search for this mapping by randomly varying the hash codes of
* colliding threads. Because search is random, and collisions
* only become known via CAS failures, convergence can be slow,
* and because threads are typically not bound to CPUS forever,
* may not occur at all. However, despite these limitations,
* observed contention rates are typically low in these cases.
*
* It is possible for a Cell to become unused when threads that
* once hashed to it terminate, as well as in the case where
* doubling the table causes no thread to hash to it under
* expanded mask. We do not try to detect or remove such cells,
* under the assumption that for long-running instances, observed
* contention levels will recur, so the cells will eventually be
* needed again; and for short-lived ones, it does not matter.
*/
/**
* Padded variant of AtomicLong supporting only raw accesses plus CAS.
* The value field is placed between pads, hoping that the JVM doesn't
* reorder them.
*
* JVM intrinsics note: It would be possible to use a release-only
* form of CAS here, if it were provided.
*/
static final class Cell {
volatile long p0, p1, p2, p3, p4, p5, p6;
volatile long value;
volatile long q0, q1, q2, q3, q4, q5, q6;
Cell(long x) { value = x; }
final boolean cas(long cmp, long val) {
return UNSAFE.compareAndSwapLong(this, valueOffset, cmp, val);
}
// Unsafe mechanics
private static final sun.misc.Unsafe UNSAFE;
private static final long valueOffset;
static {
try {
UNSAFE = getUnsafe();
Class<?> ak = Cell.class;
valueOffset = UNSAFE.objectFieldOffset
(ak.getDeclaredField("value"));
} catch (Exception e) {
throw new Error(e);
}
}
}
/**
* ThreadLocal holding a single-slot int array holding hash code.
* Unlike the JDK8 version of this class, we use a suboptimal
* int[] representation to avoid introducing a new type that can
* impede class-unloading when ThreadLocals are not removed.
*/
static final ThreadLocal<int[]> threadHashCode = new ThreadLocal<int[]>();
/**
* Generator of new random hash codes
*/
static final Random rng = new Random();
/** Number of CPUS, to place bound on table size */
static final int NCPU = Runtime.getRuntime().availableProcessors();
/**
* Table of cells. When non-null, size is a power of 2.
*/
transient volatile Cell[] cells;
/**
* Base value, used mainly when there is no contention, but also as
* a fallback during table initialization races. Updated via CAS.
*/
transient volatile long base;
/**
* Spinlock (locked via CAS) used when resizing and/or creating Cells.
*/
transient volatile int busy;
/**
* Package-private default constructor
*/
Striped64() {
}
/**
* CASes the base field.
*/
final boolean casBase(long cmp, long val) {
return UNSAFE.compareAndSwapLong(this, baseOffset, cmp, val);
}
/**
* CASes the busy field from 0 to 1 to acquire lock.
*/
final boolean casBusy() {
return UNSAFE.compareAndSwapInt(this, busyOffset, 0, 1);
}
/**
* Computes the function of current and new value. Subclasses
* should open-code this update function for most uses, but the
* virtualized form is needed within retryUpdate.
*
* @param currentValue the current value (of either base or a cell)
* @param newValue the argument from a user update call
* @return result of the update function
*/
abstract long fn(long currentValue, long newValue);
/**
* Handles cases of updates involving initialization, resizing,
* creating new Cells, and/or contention. See above for
* explanation. This method suffers the usual non-modularity
* problems of optimistic retry code, relying on rechecked sets of
* reads.
*
* @param x the value
* @param hc the hash code holder
* @param wasUncontended false if CAS failed before call
*/
final void retryUpdate(long x, int[] hc, boolean wasUncontended) {
int h;
if (hc == null) {
threadHashCode.set(hc = new int[1]); // Initialize randomly
int r = rng.nextInt(); // Avoid zero to allow xorShift rehash
h = hc[0] = (r == 0) ? 1 : r;
}
else
h = hc[0];
boolean collide = false; // True if last slot nonempty
for (;;) {
Cell[] as; Cell a; int n; long v;
if ((as = cells) != null && (n = as.length) > 0) {
if ((a = as[(n - 1) & h]) == null) {
if (busy == 0) { // Try to attach new Cell
Cell r = new Cell(x); // Optimistically create
if (busy == 0 && casBusy()) {
boolean created = false;
try { // Recheck under lock
Cell[] rs; int m, j;
if ((rs = cells) != null &&
(m = rs.length) > 0 &&
rs[j = (m - 1) & h] == null) {
rs[j] = r;
created = true;
}
} finally {
busy = 0;
}
if (created)
break;
continue; // Slot is now non-empty
}
}
collide = false;
}
else if (!wasUncontended) // CAS already known to fail
wasUncontended = true; // Continue after rehash
else if (a.cas(v = a.value, fn(v, x)))
break;
else if (n >= NCPU || cells != as)
collide = false; // At max size or stale
else if (!collide)
collide = true;
else if (busy == 0 && casBusy()) {
try {
if (cells == as) { // Expand table unless stale
Cell[] rs = new Cell[n << 1];
for (int i = 0; i < n; ++i)
rs[i] = as[i];
cells = rs;
}
} finally {
busy = 0;
}
collide = false;
continue; // Retry with expanded table
}
h ^= h << 13; // Rehash
h ^= h >>> 17;
h ^= h << 5;
hc[0] = h; // Record index for next time
}
else if (busy == 0 && cells == as && casBusy()) {
boolean init = false;
try { // Initialize table
if (cells == as) {
Cell[] rs = new Cell[2];
rs[h & 1] = new Cell(x);
cells = rs;
init = true;
}
} finally {
busy = 0;
}
if (init)
break;
}
else if (casBase(v = base, fn(v, x)))
break; // Fall back on using base
}
}
/**
* Sets base and all cells to the given value.
*/
final void internalReset(long initialValue) {
Cell[] as = cells;
base = initialValue;
if (as != null) {
int n = as.length;
for (int i = 0; i < n; ++i) {
Cell a = as[i];
if (a != null)
a.value = initialValue;
}
}
}
// Unsafe mechanics
private static final sun.misc.Unsafe UNSAFE;
private static final long baseOffset;
private static final long busyOffset;
static {
try {
UNSAFE = getUnsafe();
Class<?> sk = Striped64.class;
baseOffset = UNSAFE.objectFieldOffset
(sk.getDeclaredField("base"));
busyOffset = UNSAFE.objectFieldOffset
(sk.getDeclaredField("busy"));
} catch (Exception e) {
throw new Error(e);
}
}
/**
* Returns a sun.misc.Unsafe. Suitable for use in a 3rd party package.
* Replace with a simple call to Unsafe.getUnsafe when integrating
* into a jdk.
*
* @return a sun.misc.Unsafe
*/
private static sun.misc.Unsafe getUnsafe() {
try {
return sun.misc.Unsafe.getUnsafe();
} catch (SecurityException tryReflectionInstead) {}
try {
return java.security.AccessController.doPrivileged
(new java.security.PrivilegedExceptionAction<sun.misc.Unsafe>() {
public sun.misc.Unsafe run() throws Exception {
Class<sun.misc.Unsafe> k = sun.misc.Unsafe.class;
for (java.lang.reflect.Field f : k.getDeclaredFields()) {
f.setAccessible(true);
Object x = f.get(null);
if (k.isInstance(x))
return k.cast(x);
}
throw new NoSuchFieldError("the Unsafe");
}});
} catch (java.security.PrivilegedActionException e) {
throw new RuntimeException("Could not initialize intrinsics",
e.getCause());
}
}
}