Motivation:
MpscLinkedQueue has various issues:
- It does not work without sun.misc.Unsafe.
- Some field names are confusing.
- Node.tail does not refer to the tail node really.
- The tail node is the starting point of iteration. I think the tail
node should be the head node and vice versa to reduce confusion.
- Some important methods are not implemented (e.g. iterator())
- Not serializable
- Potential false cache sharing problem due to lack of padding
- MpscLinkedQueue extends AtomicReference and thus exposes various
operations that mutates the internal state of the queue directly.
Modifications:
- Use AtomicReferenceFieldUpdater wherever possible so that we do not
use Unsafe directly. (e.g. use lazySet() instead of putOrderedObject)
- Extend AbstractQueue to implement most operations
- Implement serialization and iterator()
- Rename tail to head and head to tail to reduce confusion.
- Rename Node.tail to Node.next.
- Fix a leak where the references in the removed head are not cleared
properly.
- Add Node.clearMaybe() method so that the value of the new head node
is cleared if possible.
- Add some comments for my own educational purposes
- Add padding to the head node
- Add FullyPaddedReference and RightPaddedReference for future reuse
- Make MpscLinkedQueue package-local so that a user cannot access the
dangerous yet public operations exposed by the superclass.
- MpscLinkedQueue.Node becomes MpscLinkedQueueNode, a top level class
Result:
- It's more like a drop-in replacement of ConcurrentLinkedQueue for the
MPSC case.
- Works without sun.misc.Unsafe
- Code potentially easier to understand
- Fixed leak (related: #2372)
Motivation:
At the moment ChannelFlushPromiseNotifier.add(....) takes an int value for pendingDataSize, which may be too small as a user may need to use a long. This can for example be useful when a user writes a FileRegion etc. Beside this the notify* method names are kind of missleading as these should not contain *Future* because it is about ChannelPromises.
Modification:
Alter add(...) method to take a long for pendingDataSize. Rename all *Future* methods to have *Promise* in the method name to better reflect usage.
Result:
ChannelFlushPromiseNotifier can be used with bigger data.
Motivation:
Currently OkResponseHandler returns a DefaultHttpResponse which is not
correct and it should be returning complete http response.
Modifications:
Updated OkResponseHandler to return an instance of
DefaultFullHttpResponse.
Result:
It is not possible to add compression to the example without getting any
errors.
Motivation:
ChannelTrafficShapingHandler may corrupt inbound data stream by
scheduling the fireChannelRead event.
Modification:
Always call fireChannelRead(...) and only suspend reads after it
Result:
No more data corruption
Motivation:
When running Netty on a container environment, the container will often
complain about the lingering threads such as the worker threads of
ThreadDeathWatcher and GlobalEventExecutor. We should provide an
operation that allows a use to wait until such threads are terminated.
Modifications:
- Add awaitInactivity()
- (misc) Fix typo in GlobalEventExecutorTest
- (misc) Port ThreadDeathWatch's CAS-based thread life cycle management
to GlobalEventExecutor
Result:
- Fixes#2084
- Less overhead on task submission of GlobalEventExecutor
Motivation:
PooledByteBufAllocator's thread local cache and
ReferenceCountUtil.releaseLater() are in need of a way to run an
arbitrary logic when a certain thread is terminated.
Modifications:
- Add ThreadDeathWatcher, which spawns a low-priority daemon thread
that watches a list of threads periodically (every second) and
invokes the specified tasks when the associated threads are not alive
anymore
- Start-stop logic based on CAS operation proposed by @tea-dragon
- Add debug-level log messages to see if ThreadDeathWatcher works
Result:
- Fixes#2519 because we don't use GlobalEventExecutor anymore
- Cleaner code
Motivation:
At the moment MessageToMessageEncoder uses ctx.write(msg) when have more then one message was produced. This may produce more GC pressure then necessary as when the original ChannelPromise is a VoidChannelPromise we can safely also use one when write messages.
Modifications:
Use VoidChannelPromise when the original ChannelPromise was of this type
Result:
Less object creation and GC pressure
Motivation:
The current DefaultAttributeMap cause an infinite-loop when the user removes an attribute and create the same attribute again. This regression was introduced by c3bd7a8ff1.
Modification:
Correctly break out loop
Result:
No infinite-loop anymore.
Motivation:
The default StringBuilder size is too small (data.length + 4) while it will be 2*data.length (byte to Hex) + 5 "-" char (since 5 peaces appended).
Modification:
Changing initial size to the correct one
Result:
Allocation of the correct final size from the beginning for this StringBuilder.
Motivation:
If we make allocateRun/SubpageSimple() always try the left node first and make allocateRun/Subpage() always tries the right node first, it is more likely that allocateRun/Subpage() will find a node with ST_UNUSED sooner.
Modifications:
- Make allocateRunSimple() and allocateSubpageSimple() always try the left node first.
- Make allocateRun() and allocateSubpage() always try the right node first.
- Remove randome
Result:
We get the same performance without using random numbers.
Motivation:
We still have a room for improvement in PoolChunk.allocateRun() and
Subpage.allocate().
Modifications:
- Unroll the recursion in PoolChunk.allocateRun()
- Subpage.allocate() makes use of the 'nextAvail' value set by previous
free().
Result:
- PoolChunk.allocateRun() optimization yields 10%+ improvements in
allocation throughput for non-subpage allocations.
- Subpage.allocate() optimization makes the subpage allocations for
tiny buffers as fast as non-tiny buffers even when the pageSize is
huge (e.g. 1048576) because it doesn't need to perform a linear search
in most cases.
Motivation:
Allocating a single buffer and releasing it repetitively for a benchmark will not involve the realistic execution path of the allocators.
Modifications:
Keep the last 8192 allocations and release them randomly.
Result:
We are now getting the result close to what we got with caliper.
Motivation:
On some ill-configured systems, InetAddress.getLocalHost() fails. NioSocketChannelTest calls java.net.Socket.connect() and it internally invoked InetAddress.getLocalHost(), which causes the test failures in NioSocketChannelTes on such an ill-configured system.
Modifications:
Use NetUtil.LOCALHOST explicitly.
Result:
NioSocketChannelTest should not fail anymore.
Motivation:
maven-antrun-plugin does not redirect stdin, and thus it's impossible to
run interactive examples such as securechat-client and telnet-client.
org.codehaus.mojo:exec-maven-plugin redirects stdin, but it buffers
stdout and stderr, and thus an application output is not flushed timely.
Modifications:
Deploy a forked version of exec-maven-plugin which flushes output
buffers in a timely manner.
Result:
Interactive examples work. Launches faster than maven-antrun-plugin.
Motivation:
The examples have not been updated since long time ago, showing various
issues fixed in this commit.
Modifications:
- Overall simplification to reduce LoC
- Use system properties to get options instead of parsing args.
- Minimize option validation
- Just use System.out/err instead of Logger
- Do not pass config as parameters - just access it directly
- Move the main logic to main(String[]) instead of creating a new
instance meaninglessly
- Update netty-build-21 to make checkstyle not complain
- Remove 'throws Exception' clause if possible
- Line wrap at 120 (previously at 80)
- Add an option to enable SSL for most examples
- Use ChannelFuture.sync() instead of await()
- Use System.out for the actual result. Use System.err otherwise.
- Delete examples that are not very useful:
- applet
- websocket/html5
- websocketx/sslserver
- localecho/multithreaded
- Add run-example.sh which simplifies launching an example from command
line
- Rewrite FileServer example
Result:
Shorter and simpler examples. A user can focus more on what it actually
does than miscellaneous stuff. A user can launch an example very
easily.
Motivation:
When (listeners == null && lateListeners == null) and (stackDepth >= MAX_LISTENER_STACK_DEPTH), the listener is not notified at all. The discard client does not work.
Modification:
Make sure to submit the notification task.
Result:
The discard client works again and all listeners are notified.
Motivation:
- dependencyVersionsDir property is not resolved during the build
process. The build doesn't fail because of this, but it creates an
ugly directory.
- All-in-one JAR contains libnetty-tcnative.so, which is not part of the
all-in-one JAR.
Modifications:
- Fix an incorrect property name
(dependencyVersionDir -> dependencyVersionsDir)
- Exclude libnetty-tcnative.so
- Remove unnecessary includes in source expanding configuration
Result:
- Cleaner pom.xml
- We do not ship libnetty-tcnative.so in all-in-one JAR anymore, which
is correct, because strictly speaking the native library belongs to
org.apache.tomcat.jni package.
Motivation:
exec-maven-plugin does not flush stdout and stderr, making the console
output from the examples invisible to users
Modification:
Use maven-antrun-plugin instead
Result:
A user sees the output from the examples immediately.
Motivation:
In the early days of 5.0, we merged ChannelInboundHandler and
ChannelOutboundHandler into ChannelHandler, and introduced the
annotation called 'Skip'. The annotation 'Skip' was introduced to
determine which handler methods are no-op (i.e. simply forwarding the
event to the next handler) so that DefaultChannelHandlerContext doesn't
even need to submit an event-invoking task to an EventExecutor,
significantly reducing the context switches.
However, this introduced a regression for the handlers which implemented
write() but not flush(). Because flush() was skippable for such
handlers, flush() event went through to the next handler before write() does.
To address this problem, we came up with a naive workaround that sets
MASK_FLUSH when MASK_WRITE is set.
Although the previous workaround works fine for many cases, we still
seem to have an event ordering problem. We keep seeing the intermittant
failure of LocalTransportThreadModelTest.testStagedExecution(), because
other handler methods are still skipped.
Modifications:
We do not skip the execution of handler methods annotated with 'Skip'
unless all inbound methods (or all outbound methods) are marked with
'Skip'.
Result:
This change Brings back the event ordering behavior of 4.x, making
LocalTransportThreadModelTest.testStagedExecution() pass.
Motivation:
According to TLS ALPN draft-05, a client sends the list of the supported
protocols and a server responds with the selected protocol, which is
different from NPN. Therefore, ApplicationProtocolSelector won't work
with ALPN
Modifications:
- Use Iterable<String> to list the supported protocols on the client
side, rather than using ApplicationProtocolSelector
- Remove ApplicationProtocolSelector
Result:
Future compatibility with TLS ALPN
Motivation:
- OpenSslEngine and JDK SSLEngine (+ Jetty NPN) have different APIs to
support NextProtoNego extension.
- It is impossible to configure NPN with SslContext when the provider
type is JDK.
Modification:
- Implement NextProtoNego extension by overriding the behavior of
SSLSession.getProtocol() for both OpenSSLEngine and JDK SSLEngine.
- SSLEngine.getProtocol() returns a string delimited by a colon (':')
where the first component is the transport protosol (e.g. TLSv1.2)
and the second component is the name of the application protocol
- Remove the direct reference of Jetty NPN classes from the examples
- Add SslContext.newApplicationProtocolSelector
Result:
- A user can now use both JDK SSLEngine and OpenSslEngine for NPN-based
protocols such as HTTP2 and SPDY
Motivation:
Mac OS X ships Bash 3, and it does not have an associative array
(declare -A).
Modifications:
Do not use an associative array.
Result:
Can run examples on Mac OS X using run-example.sh
Motivation:
- There's no way to pass an argument to an example.
- Assigning a Maven profile for each example is an overkill.
It makes the pom.xml crowded.
Modifications:
- Remove example profiles from example/pom.xml
- Keep the list of examples in run-example.sh
- run-example.sh passes all options to exec-maven-plugin.
For example, we can now do this:
./run-example.sh -Dssl -Dport=443 http-server
Result:
- It's much easier to add a new example and provide an easy way to
launch it.
- We can still pass an arbitrary argument to the example being launched.
(I'll update all examples to make them get their options from system
properties rather than from args[].
Motivation:
Build fails with JDK 8 because npn-boot does not work with JDK 8
Modifications:
Do not specify bootclasspath when on JDK 8
Result:
Build is green again.
Motivation:
Due to a known problem[1] of maven-compiler-plugin, our build always
compiles everything from scratch, which is waste of time.
Modifications:
Exclude package-info.java from the source list.
Result:
Much shorter build time.
[1]: https://jira.codehaus.org/browse/MCOMPILER-205
Motivation:
- example/pom.xml has quite a bit of duplication.
- We expect that we depend on npn-boot in more than one module in the
near future. (e.g. handler, codec-http, and codec-http2)
Modification:
- Deduplicate the profiles in example/pom.xml
- Move the build configuration related with npn-boot to the parent pom.
- Add run-example.sh that helps a user launch an example easily
Result:
- Cleaner build files
- Easier to add a new example
- Easier to launch an example
- Easier to run the tests that relies on npn-boot in the future
Motivation:
During a large memory copy, safepoint polling is diabled, hindering
accurate profiling.
Modifications:
Only copy up to 1 MiB per Unsafe.copyMemory()
Result:
Potentially more reliable performance
Motivation:
For an unknown reason, JVM of JDK8 crashes intermittently when
SslHandler feeds a direct buffer to SSLEngine.unwrap() *and* the current
cipher suite has GCM (Galois/Counter Mode) enabled.
Modifications:
Convert the inbound network buffer to a heap buffer when the current
cipher suite is using GCM.
Result:
JVM does not crash anymore.
