Motivation:
This will avoid one unncessary method invokation which will slightly improve performance.
Modifications:
Instead of calling isReadable we just check for the value of readableBytes()
Result:
Nothing functionally speaking change.
Motivation:
At the moment we have two problems:
- CompositeByteBuf.addComponent(...) will not add the supplied buffer to the CompositeByteBuf if its empty, which means it will not be released on CompositeByteBuf.release() call. This is a problem as a user will expect everything added will be released (the user not know we not added it).
- CompositeByteBuf.addComponents(...) will either add no buffers if none is readable and so has the same problem as addComponent(...) or directly release the ByteBuf if at least one ByteBuf is readable. Again this gives inconsistent handling and may lead to memory leaks.
Modifications:
- Always add the buffer to the CompositeByteBuf and so release it on release call.
Result:
Consistent handling and no buffer leaks.
Motivation:
Sometimes it's useful to be able to create a Epoll*Channel from an existing file descriptor. This is especially helpful if you integrade some c/jni code.
Modifications:
- Add extra constructor to Epoll*Channel implementations that take a FileDescriptor as an argument
- Make Rename EpollFileDescriptor to NativeFileDescriptor and make it public
- Also ensure we obtain the correct remote/local address when create a Channel from a FileDescriptor
Result:
It's now possible to create a FileDescriptor and instance a Epoll*Channel via it.
Motivation:
There are various places in OpenSslEngine wher we can do performance optimizations.
Modifications:
- Reduce JNI calls when possible
- Detect finished handshake as soon as possible
- Eliminate double calculations
- wrap multiple ByteBuffer if possible in a loop
Result:
Better performance
Motivation:
If SO_LINGER is used shutdownOutput() and close() syscalls will block until either all data was send or until the timeout exceed. This is a problem when we try to execute them on the EventLoop as this means the EventLoop may be blocked and so can not process any other I/O.
Modifications:
- Add AbstractUnsafe.closeExecutor() which returns null by default and use this Executor for close if not null.
- Override the closeExecutor() in NioSocketChannel and EpollSocketChannel and return GlobalEventExecutor.INSTANCE if getSoLinger() > 0
- use closeExecutor() in shutdownInput(...) in NioSocketChannel and EpollSocketChannel
Result:
No more blocking of the EventLoop if SO_LINGER is used and shutdownOutput() or close() is called.
Motivation:
Some of the methods are frequently called and so should be inlined if possible.
Modifications:
Give the compiler a hint that we want to inline these methods.
Result:
Better performance if inlined.
Motivation:
Older linux kernels have problems handling a large value for epoll_wait(...) and so wait for ever.
Modifications:
Adjust timeout on the fly if a too big value is passed in.
Result:
Correctly works also on older kernels.
Motivation:
The writeSpinCount was ignored in the epoll transport and it just kept on trying writing. This could cause unnessary cpu spinning if a slow remote peer was reading the data very very slow.
Modification:
- Correctly take writeSpinCount into account when writing.
Result:
Less cpu spinning when writing to a slow remote peer.
Motivation:
isRoot() is an expensive operation. We should avoid calling it if
possible.
Modifications:
Move the isRoot() checks to the end of the 'if' block, so that isRoot()
is evaluated only when really necessary.
Result:
isRoot() is evaluated only when SO_BROADCAST is set and the bind address
is anylocal address.
Motivation:
Fix regression introduced by 585ce1593f, which missed to set EPOLLRDHUP for all stream channels.
Modifications:
Correctly set EPOLLRDHUP for all stream channels in the AbstractEpollStreamChannel constructor.
Result:
No more test failures in EpollDomain*Channel tests.
Related:
- 8b2fb2b985
Motivation:
The commit mentioned above introduced a regression where
channelReadComplete() event is swallowed by a handler which was added
dynamically.
Modifications:
Do not suppress channelReadComplete() if the current handler's
channelRead() method was not invoked at all, so that a just-added
handler does not suppress channelReadComplete().
Result:
Regression is gone, and channelReadComplete() is invoked when necessary.
Motivation:
Before we used a long[] to store the ready events, this had a few problems and limitations:
- An extra loop was needed to translate between epoll_event and our long
- JNI may need to do extra memory copy if the JVM not supports pinning
- More branches
Modifications:
- Introduce a EpollEventArray which allows to directly write in a struct epoll_event* and pass it to epoll_wait.
Result:
Better speed when using native transport, as shown in the benchmark.
Before:
[xxx@xxx wrk]$ ./wrk -H 'Connection: keep-alive' -d 120 -c 256 -t 16 -s scripts/pipeline-many.lua http://xxx:8080/plaintext
Running 2m test @ http://xxx:8080/plaintext
16 threads and 256 connections
Thread Stats Avg Stdev Max +/- Stdev
Latency 14.56ms 8.64ms 117.15ms 80.58%
Req/Sec 286.17k 38.71k 421.48k 68.17%
546324329 requests in 2.00m, 73.78GB read
Requests/sec: 4553438.39
Transfer/sec: 629.66MB
After:
[xxx@xxx wrk]$ ./wrk -H 'Connection: keep-alive' -d 120 -c 256 -t 16 -s scripts/pipeline-many.lua http://xxx:8080/plaintext
Running 2m test @ http://xxx:8080/plaintext
16 threads and 256 connections
Thread Stats Avg Stdev Max +/- Stdev
Latency 14.12ms 8.69ms 100.40ms 83.08%
Req/Sec 294.79k 40.23k 472.70k 66.75%
555997226 requests in 2.00m, 75.08GB read
Requests/sec: 4634343.40
Transfer/sec: 640.85MB
Related:
- 375b9e1307
Motivation:
Even if a handler called ctx.fireChannelReadComplete(), the next handler
should not get its channelReadComplete() invoked if fireChannelRead()
was not invoked before.
Modifications:
- Ensure channelReadComplete() is invoked only when the handler of the
current context actually produced a message, because otherwise there's
no point of triggering channelReadComplete().
i.e. channelReadComplete() must follow channelRead().
- Fix a bug where ctx.read() was not called if the handler of the
current context did not produce any message, making the connection
stall. Read the new comment for more information.
Result:
- channelReadComplete() is invoked only when it makes sense.
- No stale connection
Motivation:
At the moment we log priming read and handshake errors via info log level and still throw a SSLException that contains the error. We should only log with debug level to generate less noise.
Modifications:
Change logging to debug level.
Result:
Less noise .
Motivation:
Because of a re-entrance bug in PendingWriteQueue it was possible to get the queue corrupted and also trigger an IllegalStateException caused by multiple recycling of the internal PendingWrite objects.
Modifications:
- Correctly guard against re-entrance
Result:
No more IllegalStateException possible
Motivation:
To use WebSocketClientHandshaker / WebSocketServerHandshaker it's currently a requirement of having a HttpObjectAggregator in the ChannelPipeline. This is not a big deal when a user only wants to server WebSockets but is a limitation if the server serves WebSockets and normal HTTP traffic.
Modifications:
Allow to use WebSocketClientHandshaker and WebSocketServerHandshaker without HttpObjectAggregator in the ChannelPipeline.
Result:
More flexibility
Motivation:
Netty uses edge-triggered epoll by default for performance reasons. The downside here is that a messagesPerRead limit can not be enforced correctly, as we need to consume everything from the channel when notified.
Modification:
- Allow to switch epoll modes before channel is registered
- Some refactoring to share more code
Result:
It's now possible to switch epoll mode.
Motiviation:
When using domain sockets on linux it is supported to recv and send file descriptors. This can be used to pass around for example sockets.
Modifications:
- Add support for recv and send file descriptors when using EpollDomainSocketChannel.
- Allow to obtain the file descriptor for an Epoll*Channel so it can be send via domain sockets.
Result:
recv and send of file descriptors is supported now.
Motivation:
Using Unix Domain Sockets can be very useful when communication should take place on the same host and has less overhead then using loopback. We should support this with the native epoll transport.
Modifications:
- Add support for Unix Domain Sockets.
- Adjust testsuite to be able to reuse tests.
Result:
Unix Domain Sockets are now support when using native epoll transport.
Motivation:
SonarQube (clinker.netty.io/sonar) reported a resource which may not have been properly closed in all situations in AbstractDiskHttpData.
Modifications:
- Ensure file channels are closed in the presence of exceptions.
- Correct instances where local channels were created but potentially not closed.
Result:
Less leaks. Less SonarQube vulnerabilities.
Motivation:
SonarQube (clinker.netty.io/sonar) reported a few 'critical' issues related to the OpenSslEngine.
Modifications:
- Remove potential for dereference of null variable.
- Remove duplicate null check and TODO cleanup.
Results:
Less potential for null dereference, cleaner code, and 1 less TODO.
Motivation:
`HttpResponseDecoder` and `HttpRequestDecoder` in the event when the max configured sizes for HTTP initial line, headers or content is breached, sends a `DefaultHttpResponse` and `DefaultHttpRequest` respectively. After this `HttpObjectDecoder` gets into `BAD_MESSAGE` state and ignores any other data received on this connection.
The combination of the above two behaviors, means that the decoded response/request are not complete (absence of sending `LastHTTPContent`). So, any code, waiting for a complete message will have to additionally check for decoder result to follow the correct semantics of HTTP.
If `HttpResponseDecoder` and `HttpRequestDecoder` creates a Full* invalid message then the request/response is a complete HTTP message and hence obeys the HTTP contract.
Modification:
Modified `HttpRequestDecoder`, `HttpResponseDecoder`, `RtspRequestDecoder` and `RtspResponseDecoder` to return Full* messages from `createInvalidMessage()`
Result:
Fixes the wrong behavior of sending incomplete messages from these codecs
Motivation:
SslHandler adds a pending write with an empty buffer and a VoidChannelPromise when a user flush and not pending writes are currently stored. This may produce an IllegalStateException later if the user try to add a ChannelFutureListener to the promise in the next ChannelOutboundHandler.
Modifications:
Replace ctx.voidPromise() with ctx.newPromise()
Result:
No more IllegalStateException possible
Motivation:
At the moment the max number of events that can be handled per epoll wakup was set during construction.
Modifications:
- Automatically increase the max number of events to handle
Result:
Better performance when a lot of events need to be handled without adjusting the code.
Motivation:
The current way how the guard against overflow when generating the nextId() is pretty slow once an overflow happened.
Modifications:
Once a possible overflow is detected all ids used by the EpollEventLoop are scrubed and re-assigned to the registered Channels. This way we only need to do extra work each time an overflow is detected.
Result:
More consistent performance even after the first overflow was detected.
Motivation:
SSLEngine specifies that IllegalArgumentException must be thrown if a null argument is given when using wrap(...) or unwrap(...).
Modifications:
Replace NullPointerException with IllegalArgumentException to match the javadocs.
Result:
Match the javadocs.
Motivation:
We failed to correctly calculate the endOffset when wrap multiple ByteBuffer and so not wrapped everything when an offset > 0 is used.
Modifications:
Correctly calculate endOffset.
Result:
All ByteBuffers are correctly wrapped when offset > 0.
Motivation:
As the ByteBuf is not set to null after release it we may try to release it again in handleReadException()
Modifications:
- set ByteBuf to null to avoid another byteBuf.release() to be called in handleReadException()
Result:
No IllegalReferenceCountException anymore
Motivation:
On Linux, you can gather various metrics using getsockopt(..., TCP_INFO,
...).
Modifications:
Add EpollSocketChannel.tcpInfo() which returns EpollTcpInfo that exposes
all metrics exposed via getsockopt(..., TCP_INFO, ...)
Result:
TCP_INFO support implemented
Motivation:
The JdkZlibDecoder and JZlibDecoder call isReadable and readableBytes in the same method. There is an opportunity to reduce the number of methods calls to just use readableBytes. JdkZlibDecoder reads from a ByteBuf with an absolute index instead of using readerIndex()
Modifications:
- Use readableBytes where isReadable was used
- Correct absolute ByteBuf index to be relative to readerIndex()
Result:
Less method calls duplicating work and preventing an index out of bounds exception.
Motivation:
In the native transport we use getpeername to obtain the remote address from the file descriptor. This may fail for various reasons in which case NULL is returned.
Modifications:
- Check for null when try to obtain remote / local address
Result:
No more NPE
Motivation:
ctx.fireChannelReadComplete() should only be called if something is produced during a channelRead(...) operation. Also we must ensure that it will be called
if channelRead(...) produced something at some point as channelRead(...) maybe called multiple times by the transport before channelReadComplete(...) is called.
Modifications:
- Ensure channelReadComplete(...) only triggers ctx.fireChannelReadComplete() when a previous channelRead(...) call produced a message
- Ensure read() is called of more data is needed
Result:
Correct semantic with channelReadComplete(...) events and also ensure no stales
Motivation:
Internet Explorer doesn't honor Set-Cookie header Max-Age attribute. It only honors the Expires one.
Modification:
Always generate an Expires attribute along the Max-Age one.
Result:
Internet Explorer compatible expiring cookies. Close#1466.
Motivation:
HttpContentDecoder had the following issues:
- For chunked content, the decoder set invalid "Content-Length" header
with length of the first decoded chunk.
- Decoding of FullHttpRequests put both the original conent and decoded
content into output. As result, using HttpObjectAggregator before the
decoder lead to errors.
- Requests with "Expect: 100-continue" header were not acknowleged:
the decoder didn't pass the header message down the handler's chain
until content is received. If client expected "100 Continue" response,
deadlock happened.
Modification:
- Invalid "Content-Length" header is removed; handlers down the chain can either
rely on LastHttpContent message or ask HttpObjectAggregator to add the header.
- FullHttpRequest is split into HttpRequest and HttpContent (decoded) parts.
- Header (HttpRequest) part of request is sent down the chain as soon as it's received.
Result:
The issues are fixed, unittest is added.
Motivation:
HttpPostMultipartRequestDecoder threw an ArrayIndexOutOfBoundsException
when trying to decode Content-Disposition header with filename
containing ';' or protected \\".
See issue #3326 and #3327.
Modifications:
Added splitMultipartHeaderValues method which cares about quotes, and
use it in splitMultipartHeader method, instead of StringUtils.split.
Result:
Filenames can contain semicolons and protected \\".
Motivation:
When SslHandler.unwrap() copies SSL records into a heap buffer, it does
not update the start offset, causing IndexOutOfBoundsException.
Modifications:
- Copy to a heap buffer before calling unwrap() for simplicity
- Do not copy an empty buffer to a heap buffer.
- unwrap(... EMPTY_BUFFER ...) never involves copying now.
- Use better parameter names for unwrap()
- Clean-up log messages
Result:
- Bugs fixed
- Cleaner code
Motivation:
When using OpenSslEngine with the SslHandler it is possible to reduce memory copies by unwrap(...) multiple ByteBuffers at the same time. This way we can eliminate a memory copy that is needed otherwise to cumulate partial received data.
Modifications:
- Add OpenSslEngine.unwrap(ByteBuffer[],...) method that can be used to unwrap multiple src ByteBuffer a the same time
- Use a CompositeByteBuffer in SslHandler for inbound data so we not need to memory copy
- Add OpenSslEngine.unwrap(ByteBuffer[],...) in SslHandler if OpenSslEngine is used and the inbound ByteBuf is backed by more then one ByteBuffer
- Reduce object allocation
Result:
SslHandler is faster when using OpenSslEngine and produce less GC
Motivation:
The SpdyHttpDecoder was modified to support pushed resources that are
divided into multiple frames. The decoder accepts a pushed
SpdySynStreamFrame containing the request headers, followed by a
SpdyHeadersFrame containing the response headers.
Modifications:
This commit modifies the SpdyHttpEncoder so that it encodes pushed
resources in a format that the SpdyHttpDecoder can decode. The encoder
will accept an HttpRequest object containing the request headers,
followed by an HttpResponse object containing the response headers.
Result:
The SpdyHttpEncoder will create a SpdySynStreamFrame followed by a
SpdyHeadersFrame when sending pushed resources.
Motivation:
NioUdtMessageRendezvoudChannelTest.basicEcho() is flakey on Linux and
failing on Windows.
Modifications:
Disable the problematic test until it's fixed.
Result:
Less annoyance
Motivation:
Currently when there are bytes left in the cumulation buffer we do a byte copy to produce the input buffer for the decode method. This can put quite some overhead on the impl.
Modification:
- Use a CompositeByteBuf to eliminate the byte copy.
- Allow to specify if a CompositeBytebug should be used or not as some handlers can only act on one ByteBuffer in an efficient way (like SslHandler :( ).
Result:
Performance improvement as shown in the following benchmark.
Without this patch:
[xxx@xxx ~]$ ./wrk-benchmark
Running 5m test @ http://xxx:8080/plaintext
16 threads and 256 connections
Thread Stats Avg Stdev Max +/- Stdev
Latency 20.19ms 38.34ms 1.02s 98.70%
Req/Sec 241.10k 26.50k 303.45k 93.46%
1153994119 requests in 5.00m, 155.84GB read
Requests/sec: 3846702.44
Transfer/sec: 531.93MB
With the patch:
[xxx@xxx ~]$ ./wrk-benchmark
Running 5m test @ http://xxx:8080/plaintext
16 threads and 256 connections
Thread Stats Avg Stdev Max +/- Stdev
Latency 17.34ms 27.14ms 877.62ms 98.26%
Req/Sec 252.55k 23.77k 329.50k 87.71%
1209772221 requests in 5.00m, 163.37GB read
Requests/sec: 4032584.22
Transfer/sec: 557.64MB
