Motivation:
Previously, we used SecureRandom.nextLong() to generate the initialSeedUniquifier. This required more entrophy than necessary because it has to 1) generate the seed of SecureRandom first and then 2) generate a random long integer. Instead, we can use generateSeed() to skip the step (2)
Modifications:
Use generateSeed() instead of nextLong()
Result:
ThreadLocalRandom requires less amount of entrphy to start up
Motivation:
As reported in #2331, some query operations in NetworkInterface takes much longer time than we expected. For example, specifying -Djava.net.preferIPv4Stack=true option in Window increases the execution time by more than 4 times. Some Windows systems have more than 20 network interfaces, and this problem gets bigger as the number of unused (virtual) NICs increases.
Modification:
Use NetworkInterface.getInetAddresses() wherever possible.
Before iterating over all NICs reported by NetworkInterface, filter the NICs without proper InetAddresses. This reduces the number of candidates quite a lot.
NetUtil does not query hardware address of NIC in the first place but uses InetAddress.isLoopbackAddress().
Do not call unnecessary query operations on NetworkInterface. Just get hardware address and compare.
Result:
Significantly reduced class initialization time
Motivation:
6e8ba291cf introduced a regression in Android because Android does not have sun.nio.ch.DirectBuffer (see #2330.) I also found PlatformDependent0.freeDirectBuffer() and freeDirectBufferUnsafe() are pretty much same after the commit and the unsafe version should be removed.
Modifications:
- Merge PlatformDependent0.freeDirectBuffer() and freeDirectBufferUnsafe() into one method.
- Make the Unsafe unavailable when sun.nio.ch.DirectBuffer is unavailable. We could keep the Unsafe available and handle the sun.nio.ch.DirectBuffer case separately, but I don't want to complicate our code just because of that. All supported JDK versions have sun.nio.ch.DirectBuffer if the Unsafe is available.
Result:
Simpler code. Fixes Android support (#2330)
Motivation:
Remove the synchronization bottleneck in startThread() which is called by each execute(..) call from outside the EventLoop.
Modifications:
Replace the synchronized block with the use of AtomicInteger and compareAndSet loops.
Result:
Less conditions during SingleThreadEventExecutor.execute(...)
Motivation:
- As reported recently [1], Recycler's thread-local object pool has unbounded capacity which is a potential problem.
- It accesses a hash table on each push and pop for debugging purposes. We don't really need it besides debugging Netty itself.
Modifications:
- Introduced the maxCapacity constructor parameter to Recycler. The default default maxCapacity is retrieved from the system property whose default is 256K, which should be plenty for most cases.
- Recycler.Stack.map is now created and accessed only when assertion is enabled for Recycler.
Result:
- Recycler does not grow infinitely anymore.
- If assertion is disabled, Recycler should be much faster.
[1] https://github.com/netty/netty/issues/1841
Previously ConcurrentHashMapV8 evaulated ((x | 1) == 0), an expression
that always returned false. This commit brings Netty closer to the
Java 8 implementation.
This transport use JNI (C) to directly make use of epoll in Edge-Triggered mode for maximal performance on Linux. Beside this it also support using TCP_CORK and produce less GC then the NIO transport using JDK NIO.
It only builds on linux and skip the build if linux is not used. The transport produce a jar which contains all needed .so files for 32bit and 64 bit. The user only need to include the jar as dependency as usually
to make use of it and use the correct classes.
This includes also some cleanup of @trustin
- Fixes#2220
- Its Javadoc says it returns true when the promise is done (but not cancelled) or the promise is uncancellable, but it returns false when the promise is done.
.. which occurs when a user adds a listener from different threads after the promise is done and the notifications for the listeners, that were added before the promise is done, is in progress. For instance:
Thread-1: p.addListener(listenerA);
Thread-1: p.setSuccess(null);
Thread-2: p.addListener(listenerB);
Thread-2: p.executor.execute(taskNotifyListenerB);
Thread-1: p.executor.execute(taskNotifyListenerA);
taskNotifyListenerB should not really notify listenerB until taskNotifyListenerA is finished.
To fix this issue:
- Change the semantic of (listeners == null) to determine if the early
listeners [1] were notified
- If a late listener is added before the early listeners are notified,
the notification of the late listener is deferred until the early
listeners are notified (i.e. until listeners == null)
- The late listeners with deferred notifications are stored in a lazily
instantiated queue to preserve ordering, and then are notified once
the early listeners are notified.
[1] the listeners that were added before the promise is done
[2] the listeners that were added after the promise is done
