2b9f69ac38
Motivation Currently an epoll_ctl syscall is made every time there is a change to the event interest flags (EPOLLIN, EPOLLOUT, etc) of a channel. These are only done in the event loop so can be aggregated into 0 or 1 such calls per channel prior to the next call to epoll_wait. Modifications I think further streamlining/simplification is possible but for now I've tried to minimize structural changes and added the aggregation beneath the existing flag manipulation logic. A new AbstractChannel#activeFlags field records the flags last set on the epoll fd for that channel. Calls to setFlag/clearFlag update the flags field as before but instead of calling epoll_ctl immediately, just set or clear a bit for the channel in a new bitset in the associated EpollEventLoop to reflect whether there's any change to the last set value. Prior to calling epoll_wait the event loop makes the appropriate epoll_ctl(EPOLL_CTL_MOD) call once for each channel who's bit is set. Result Fewer syscalls, particularly in some auto-read=false cases. Simplified error handling from centralization of these calls.
Netty Project
Netty is an asynchronous event-driven network application framework for rapid development of maintainable high performance protocol servers & clients.
Links
How to build
For the detailed information about building and developing Netty, please visit the developer guide. This page only gives very basic information.
You require the following to build Netty:
- Latest stable Oracle JDK 7
- Latest stable Apache Maven
- If you are on Linux, you need additional development packages installed on your system, because you'll build the native transport.
Note that this is build-time requirement. JDK 5 (for 3.x) or 6 (for 4.0+) is enough to run your Netty-based application.
Branches to look
Development of all versions takes place in each branch whose name is identical to <majorVersion>.<minorVersion>. For example, the development of 3.9 and 4.0 resides in the branch '3.9' and the branch '4.0' respectively.
Usage with JDK 9
Netty can be used in modular JDK9 applications as a collection of automatic modules. The module names follow the reverse-DNS style, and are derived from subproject names rather than root packages due to historical reasons. They are listed below:
io.netty.allio.netty.bufferio.netty.codecio.netty.codec.dnsio.netty.codec.haproxyio.netty.codec.httpio.netty.codec.http2io.netty.codec.memcacheio.netty.codec.mqttio.netty.codec.redisio.netty.codec.smtpio.netty.codec.socksio.netty.codec.stompio.netty.codec.xmlio.netty.commonio.netty.handlerio.netty.handler.proxyio.netty.resolverio.netty.resolver.dnsio.netty.transportio.netty.transport.epoll(nativeomitted - reserved keyword in Java)io.netty.transport.kqueue(nativeomitted - reserved keyword in Java)io.netty.transport.unix.common(nativeomitted - reserved keyword in Java)io.netty.transport.rxtxio.netty.transport.sctpio.netty.transport.udt
Automatic modules do not provide any means to declare dependencies, so you need to list each used module separately
in your module-info file.