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Norman Maurer d96c02fc68 Reduce direct memory overhead per EpollEventLoop when using EpollDatagramChannel (#8825)
Motivation:

When using a linux distribution that supports sendmmsg(...) we allocated enough direct memory per EpollEventLoop to be able to write IOV_MAX number of iovecs per message that can be written per sendmmsg.
The number of messages that can be written per sendmmsg(...) call is limited by UIO_MAX_IOV.

In practice this resulted in an allocation of 16MB direct memory per EpollEventLoop instance that stayed allocated until the EpollEventLoop was shutdown which happens as part of the shutdown of the enclosing EpollEVentLoopGroup.

This resulted in quite some heavy direct memory usage in practice even when in practice we have very slim changes to ever need all of the memory.

Modification:

Adjust NativeDatagramPacketArray to share one IovArray instance across all NativeDatagramPacket instances it holds. This limits the max number of iovecs we can write across all messages to IOV_MAX per sendmmsg(...) call.
This in practice will still be enough to allow us to write multiple messages with one syscall while keep the memory overhead to a minimum.

Result:

Smaller direct memory footprint per EpollEventLoop when using EpollDatagramChannel on distributions that support sendmmsg(...).
Fixes https://github.com/netty/netty/issues/8814
2019-02-02 07:14:53 +01:00
.github Use GitHub Issue/PR Template Feature 2016-12-07 11:40:26 -08:00
.mvn support publishing snapshots from docker based ci (#8634) 2018-12-07 06:16:39 +01:00
all Remove OIO transport (and transports that depend on it). (#8580) 2018-11-21 15:23:18 +01:00
bom Remove OIO transport (and transports that depend on it). (#8580) 2018-11-21 15:23:18 +01:00
buffer CompositeByteBuf tidy-up (#8784) 2019-02-01 10:32:02 +01:00
codec Remove ChannelHandler.exceptionCaught(...) as it should only exist in… (#8822) 2019-01-31 20:29:17 +01:00
codec-dns Java 8 migration. Remove ThreadLocalProvider and inline java.util.concurrent.ThreadLocalRandom.current() where necessary. (#8762) 2019-01-22 20:14:28 +01:00
codec-haproxy migrate java8 (#8779) 2019-01-28 05:55:30 +01:00
codec-http Replace custome readAllFile method with Files.readAllBytes (#8828) 2019-02-01 16:45:20 +01:00
codec-http2 Remove ChannelHandler.exceptionCaught(...) as it should only exist in… (#8822) 2019-01-31 20:29:17 +01:00
codec-memcache Correcting Maven Dependencies (#8622) 2018-12-06 09:02:00 +01:00
codec-mqtt Java 8 migration: Use diamond operator (#8749) 2019-01-22 16:07:26 +01:00
codec-redis Java 8 migration: Use diamond operator (#8749) 2019-01-22 16:07:26 +01:00
codec-smtp migrate java8 (#8779) 2019-01-28 05:55:30 +01:00
codec-socks migrate java8: use lambda and method reference (#8781) 2019-01-29 14:06:05 +01:00
codec-stomp Remove support for marking reader and writerIndex in ByteBuf to reduce overhead and complexity. (#8636) 2018-12-11 14:00:49 +01:00
codec-xml Update to new checkstyle plugin (#8777) 2019-01-24 16:24:19 +01:00
common Fix varargs parameter logging in LocationAwareSlf4JLogger (#8834) 2019-02-02 07:08:58 +01:00
dev-tools Update version number to start working on Netty 5 2018-11-20 15:49:57 +01:00
docker Update to latest JDK8 and JDK11 releases (#8725) 2019-01-17 09:14:42 +01:00
example Compare HttpMethod by reference (#8815) 2019-01-30 21:17:24 +01:00
handler migrate java8: use lambda and method reference (#8781) 2019-01-29 14:06:05 +01:00
handler-proxy migrate java8: use lambda and method reference (#8781) 2019-01-29 14:06:05 +01:00
license Add the NOTICE of the forked portion of Apache Harmony 2018-01-30 11:22:51 +01:00
microbench Remove ChannelHandler.exceptionCaught(...) as it should only exist in… (#8822) 2019-01-31 20:29:17 +01:00
resolver migrate java8: use lambda and method reference (#8781) 2019-01-29 14:06:05 +01:00
resolver-dns migrate java8: use lambda and method reference (#8781) 2019-01-29 14:06:05 +01:00
tarball Update version number to start working on Netty 5 2018-11-20 15:49:57 +01:00
testsuite Reduce GC produced by native DatagramChannel implementations when in connected mode. (#8806) 2019-02-01 10:29:55 +01:00
testsuite-autobahn Compare HttpMethod by reference (#8815) 2019-01-30 21:17:24 +01:00
testsuite-http2 use checkPositive/checkPositiveOrZero (#8803) 2019-01-31 09:06:59 +01:00
testsuite-osgi Java 8 migration: Use diamond operator (#8749) 2019-01-22 16:07:26 +01:00
testsuite-shading Update version number to start working on Netty 5 2018-11-20 15:49:57 +01:00
transport Remove ChannelHandler.exceptionCaught(...) as it should only exist in… (#8822) 2019-01-31 20:29:17 +01:00
transport-native-epoll Reduce direct memory overhead per EpollEventLoop when using EpollDatagramChannel (#8825) 2019-02-02 07:14:53 +01:00
transport-native-kqueue Reduce GC produced by native DatagramChannel implementations when in connected mode. (#8806) 2019-02-01 10:29:55 +01:00
transport-native-unix-common use checkPositive/checkPositiveOrZero (#8803) 2019-01-31 09:06:59 +01:00
transport-native-unix-common-tests Correcting Maven Dependencies (#8622) 2018-12-06 09:02:00 +01:00
transport-sctp use checkPositive/checkPositiveOrZero (#8803) 2019-01-31 09:06:59 +01:00
.fbprefs Updated Find Bugs configuration 2009-03-04 10:33:09 +00:00
.gitattributes Include mvn wrapper to make setup of development env easier 2018-01-26 08:13:17 +01:00
.gitignore Exclude mainframer related files from git 2018-10-14 13:20:18 +02:00
CONTRIBUTING.md Move the pull request guide to the developer guide 2014-03-12 13:13:58 +09:00
LICENSE.txt Relicensed to Apache License v2 2009-08-28 07:15:49 +00:00
mvnw Include mvn wrapper to make setup of development env easier 2018-01-26 08:13:17 +01:00
mvnw.cmd Include mvn wrapper to make setup of development env easier 2018-01-26 08:13:17 +01:00
NOTICE.txt Add the NOTICE of the forked portion of Apache Harmony 2018-01-30 11:22:51 +01:00
pom.xml Update to new checkstyle plugin (#8777) 2019-01-24 16:24:19 +01:00
README.md Provide an Automatic-Module-Name for the netty-all artifact fixes #7644 2018-01-27 20:31:16 +01:00
run-example.sh Add UptimeServer and adjust UptimeClient's code style. 2017-04-28 07:41:07 +02:00

Netty Project

Netty is an asynchronous event-driven network application framework for rapid development of maintainable high performance protocol servers & clients.

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:

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.all
  • io.netty.buffer
  • io.netty.codec
  • io.netty.codec.dns
  • io.netty.codec.haproxy
  • io.netty.codec.http
  • io.netty.codec.http2
  • io.netty.codec.memcache
  • io.netty.codec.mqtt
  • io.netty.codec.redis
  • io.netty.codec.smtp
  • io.netty.codec.socks
  • io.netty.codec.stomp
  • io.netty.codec.xml
  • io.netty.common
  • io.netty.handler
  • io.netty.handler.proxy
  • io.netty.resolver
  • io.netty.resolver.dns
  • io.netty.transport
  • io.netty.transport.epoll (native omitted - reserved keyword in Java)
  • io.netty.transport.kqueue (native omitted - reserved keyword in Java)
  • io.netty.transport.unix.common (native omitted - reserved keyword in Java)
  • io.netty.transport.rxtx
  • io.netty.transport.sctp
  • io.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.