Motivation:
java.nio.channels.spi.AbstractSelectableChannel.register(...) need to obtain multiple locks during execution which may produce a long wait time if we currently select. This lead to multiple CI failures in the past.
Modifications:
Ensure the register call takes place on the EventLoop.
Result:
No more flacky CI test timeouts.
Motivation:
During benchmarks two methods showed up as "hot method too big". We can easily make these smaller by factor out some less common code-path to an extra method and so allow inlining.
Modifications:
Factor out less common code path to an extra method.
Result:
Hot methods can be inlined.
Motivation:
Our HeadContext in DefaultChannelPipeline does handle inbound and outbound but we only marked it as outbound. While this does not have any effect in the current code-base it can lead to problems when we change our internals (this is also how I found the bug).
Modifications:
Construct HeadContext so it is also marked as handling inbound.
Result:
More correct code.
Motivation:
31fd66b617 added @Deprecated to some classes but also to the package-info.java files. IntelliJ does not like to have these annotations on package-info.java
Modifications:
Remove annotation from package-info.java
Result:
Be able to compile against via IntelliJ
Motivation:
We plan to remove the OIO based transports in Netty 5 so we should mark these as deprecated already.
Modifications:
Mark all OIO based transports as deprecated.
Result:
Give the user a heads-up for removal.
Motivation:
When the Selector throws an IOException during our EventLoop processing we should rebuild it and transfer the registered Channels. At the moment we will continue trying to use it which will never work.
Modifications:
- Rebuild Selector when an IOException is thrown during any select*(...) methods.
- Add unit test.
Result:
Fixes https://github.com/netty/netty/issues/8566.
Motivation:
Besides an error caused by closing socket in Windows a bunch of other errors may happen at this place which won't be somehow logged. For instance any VirtualMachineError as OutOfMemoryError will be simply ignored. The library should at least log the problem.
Modification:
Added logging of the throwable object.
Result:
Fixes#8499.
Motivation:
There is a racy UnsupportedOperationException instead because the task removal is delegated to MpscChunkedArrayQueue that does not support removal. This happens with SingleThreadEventExecutor that overrides the newTaskQueue to return an MPSC queue instead of the LinkedBlockingQueue returned by the base class such as NioEventLoop, EpollEventLoop and KQueueEventLoop.
Modifications:
- Catch the UnsupportedOperationException
- Add unit test.
Result:
Fix#8475
Motivation:
There are currently many more places where this could be used which were
possibly not considered when the method was added.
If https://github.com/netty/netty/pull/8388 is included in its current
form, a number of these places could additionally make use of the same
BYTE_ARRAYS threadlocal.
There's also a couple of adjacent places where an optimistically-pooled
heap buffer is used for temp byte storage which could use the
threadlocal too in preference to allocating a temp heap bytebuf wrapper.
For example
https://github.com/netty/netty/blob/4.1/buffer/src/main/java/io/netty/buffer/ByteBufUtil.java#L1417.
Modifications:
Replace new byte[] with PlatformDependent.allocateUninitializedArray()
where appropriate; make use of ByteBufUtil.getBytes() in some places
which currently perform the equivalent logic, including avoiding copy of
backing array if possible (although would be rare).
Result:
Further potential speed-up with java9+ and appropriate compile flags.
Many of these places could be on latency-sensitive code paths.
Motivation:
It has shown that the used test timeout may be too low when the CI is busy.
Modifications:
Increase timeout to 3 seconds.
Result:
Less false-positives.
Motivation:
Currently we may end up in the situation that we incremented the pending bytes before submitting the AbstractWriteTask but never decrement these again if the submitting of the task fails. This may result in incorrect watermark handling.
Modifications:
- Correctly decrement pending bytes if subimitting of task fails and also ensure we recycle it correctly.
- Add unit test.
Result:
Fixes https://github.com/netty/netty/issues/8343.
Motivation:
Unless the 'io.netty.noKeySetOptimization' system property is set,
registering a SelectableChannel instance to a NioEventLoop results
in a ClassCastException:
io.netty.channel.nio.SelectedSelectionKeySetSelector cannot be cast
to java.nio.channels.spi.AbstractSelector
Modifications:
Instead of 'selector', pass 'unwrappedSelector' to SelectableChannel.
Result:
It is possible to register a SelectableChannel instance without
setting the 'io.netty.noKeySetOptimization' system property.
Motivation:
Add an option (through a SelectStrategy return code) to have the Netty event loop thread to do busy-wait on the epoll.
The reason for this change is to avoid the context switch cost that comes when the event loop thread is blocked on the epoll_wait() call.
On average, the context switch has a penalty of ~13usec.
This benefits both:
The latency when reading from a socket
Scheduling tasks to be executed on the event loop thread.
The tradeoff, when enabling this feature, is that the event loop thread will be using 100% cpu, even when inactive.
Modification:
Added SelectStrategy option to return BUSY_WAIT
Epoll loop will do a epoll_wait() with no timeout
Use pause instruction to hint to processor that we're in a busy loop
Result:
When enabled, minimizes impact of context switch in the critical path
Motivation:
In Java8 and earlier we used reflection to replace the used key set if not otherwise told. This does not work on Java9 and later without special flags as its not possible to call setAccessible(true) on the Field anymore.
Modifications:
- Use Unsafe to instrument the Selector with out special set when sun.misc.Unsafe is present and we are using Java9+.
Result:
NIO transport produce less GC on Java9 and later as well.
Motivation:
We need to implement remove() by ourselves to make it work on Java7 as otherwise it will throw an AbstractMethodError. This is a followup of c1a335446d.
Modifications:
Just implemented remove()
Result:
Works on Java7 as well.
Motivation:
c1a335446d reimplemented remove(...) and contains(...) in a way which made it not work anymore when used by the Selector.
Modifications:
Partly revert changes in c1a335446d.
Result:
Works again as expected
Motivation:
Our SelectedSelectionKeySet does not correctly implement various methods which can be done without any performance overhead.
Modifications:
Implement iterator(), contains(...) and remove(...)
Result:
Related to https://github.com/netty/netty/issues/8242.
Motivation:
It seems to sometimes confuse people what to do to replace setMaxMessagePerRead(...).
Modifications:
Add some more details to the javadocs about the correct replacement.
Result:
Related to https://github.com/netty/netty/issues/8214.
Motivation:
We had a report that the exception may not be correctly propagated. This test shows it is.
Modifications:
Add testcase.
Result:
Test for https://github.com/netty/netty/issues/8158
Motivation:
There is a JDK bug which will return IP_TOS as supported option for ServerSocketChannel even if its not supported afterwards and cause an AssertionError.
See http://mail.openjdk.java.net/pipermail/nio-dev/2018-August/005365.html.
Modifications:
Add a workaround for the JDK bug.
Result:
ServerSocketChannel.config().getOptions() will not throw anymore and work as expected.
Motivation:
952eeb8e1e introduced the possibility to use any JDK SocketOption when using the NIO transport but broke the possibility to use netty with java6.
Modifications:
Do not use java7 types in method signatures of the static methods in NioChannelOption to prevent class-loader issues on java6.
Result:
Fixes https://github.com/netty/netty/issues/8166.
* Support the usage of SocketOption when nio is used and the java version >= 7.
Motivation:
The JDK uses SocketOption since java7 to support configuration options on the underyling Channel. We should allow to create a ChannelOption from a given SocketOption if nio is used. This also allows us to expose the same featureset in terms of configuration as the java nio implementation does without any extra effort.
Modifications:
- Add NioChannelOption which allows to wrap an existing SocketOption which then can be applied to the nio transport.
- Add test-cases
Result:
Support the same configuration options as the JDK. Also fixes https://github.com/netty/netty/issues/8072.
Motivation:
Some code that was shown as part of the ChannelHandler javadoc was not 100 % correct and used some constructs that we used in netty 3. Also we never called flush() in the code which is a bad example for users.
Modifications:
- Remove netty 3 code references
- Replace channel.write(...) with ctx.writeAndFlush(...)
Result:
More correct code in the javadocs.
Motivation:
Currently, the vast majority of userEventTriggered() implementations
require the user to supply the boilerplate behavior of performing an
instanceof check, handling if appropriate, and calling
fireUserEventTriggered() otherwise.
We can simplify this very common use case by creating a class that only
matches user events of a given type, similar to the existing
SimpleChannelInboundHandler class.
Modifications:
Create a new SimpleUserEventChannelHandler class
Create accompanying SimpleUserEventChannelHandlerTest class
Result:
Users will be able to handle most events in a less verbose manner.
Motivation:
We use FixedChannelPool in production, and we believe we have a leak that doesn't return sockets to the pool (but they should be closed), thus blocking us from creating new connections when we need them. I haven't confirmed this yet, but right now I have to resort to reflection to access this field which makes me sad.
Modification:
Expose the acquiredChannelCount field through a getter method.
Result:
Allows introspection of the pool size in FixedChannelPool.
Motivation
There is a cost to concatenating strings and calling methods that will be wasted if the Logger's level is not enabled.
Modifications
Check if Log level is enabled before producing log statement. These are just a few cases found by RegEx'ing in the code.
Result
Tiny bit more efficient code.
Motivation:
If we can not replace the internal used Set of the Selector there is no need to create an SelectedSelectionKeySet instance.
Modification:
Only create SelectedSelectionKeySet if we will replace the internal set.
Result:
Less object creation in some cases and cleaner code.
Motivation:
We should allow to schedule tasks with a delay up to Long.MAX_VALUE as we did pre 4.1.25.Final.
Modifications:
Just ensure we not overflow and put the correct max limits in place when schedule a timer. At worse we will get a wakeup to early and then schedule a new timeout.
Result:
Fixes https://github.com/netty/netty/issues/7970.
Motivation:
A long time ago we deprecated AUTO_CLOSE but it turned out this feature is still useful because if a write error is detected there still maybe data to read, and if we close the channel automatically we will lose data
Modifications:
- Remove `@Deprecated` tag for AUTO_CLOSE, setAutoClose(...) and isAutoClose(...)
- Fix javadocs on ChannelConfig to correctly tell the default value of AUTO_CLOSE.
Result:
Less warnings.
Motivation:
We need to ensure we only return from close() after all work is done as otherwise we may close the EventExecutor before we dispatched everything.
Modifications:
Correctly wait on operations to complete before return.
Result:
Fixes https://github.com/netty/netty/issues/7901.
