166caf96ef
Motivation The recently-introduced event loop scheduling hooks can be exploited by the epoll transport to avoid waking the event loop when scheduling future tasks if there is a timer already set to wake up sooner. There is also a "default" timeout which will wake the event loop after 1 second if there are no pending future tasks. The performance impact of these wakeups themselves is likely negligible but there's significant overhead in having to re-arm the timer every time the event loop goes to sleep (see #7816). It's not 100% clear why this timeout was there originally but we're sure it's no longer needed. Modification Combine the existing volatile wakenUp and non-volatile prevDeadlineNanos fields into a single AtomicLong that stores the next scheduled wakeup time while the event loop is in epoll_wait, and is -1 while it is awake. Use this as a guard to debounce wakeups from both immediate scheduled tasks and future scheduled tasks, the latter using the new before/afterScheduledTaskSubmitted overrides and based on whether the new deadline occurs prior to an already-scheduled timer. A similar optimization was already added to NioEventLoop, but it still uses two separate volatiles. We should consider similar streamlining of that in a future update. Result Fewer event loop wakeups when scheduling future tasks, greatly reduced overhead when no future tasks are scheduled. |
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| .github | ||
| .mvn | ||
| all | ||
| bom | ||
| buffer | ||
| codec | ||
| codec-dns | ||
| codec-haproxy | ||
| codec-http | ||
| codec-http2 | ||
| codec-memcache | ||
| codec-mqtt | ||
| codec-redis | ||
| codec-smtp | ||
| codec-socks | ||
| codec-stomp | ||
| codec-xml | ||
| common | ||
| dev-tools | ||
| docker | ||
| example | ||
| handler | ||
| handler-proxy | ||
| license | ||
| microbench | ||
| resolver | ||
| resolver-dns | ||
| tarball | ||
| testsuite | ||
| testsuite-autobahn | ||
| testsuite-http2 | ||
| testsuite-native-image | ||
| testsuite-osgi | ||
| testsuite-shading | ||
| transport | ||
| transport-native-epoll | ||
| transport-native-kqueue | ||
| transport-native-unix-common | ||
| transport-native-unix-common-tests | ||
| transport-rxtx | ||
| transport-sctp | ||
| transport-udt | ||
| .fbprefs | ||
| .gitattributes | ||
| .gitignore | ||
| CONTRIBUTING.md | ||
| LICENSE.txt | ||
| mvnw | ||
| mvnw.cmd | ||
| NOTICE.txt | ||
| pom.xml | ||
| README.md | ||
| run-example.sh | ||
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.