This is a repository containing a modified version of the 5.1.5 Linux kernel to support features of RSS++:
- Support for giving the "hash" from RSS to a BPF XDP program. Just to avoid recomputing the hash in software.
- SO_AUTOMIGRATE allows to migrate a thread doing a read on a socket to the core where the last packet was received. Of course, this is to be used in a sharding context where all packets of the same flow are handled on the same core. With RSS++, flows may be migrated, and the thread will therefore migrate with it at its next read call.
- SO_SHARDED allows to use per-core flow table. Unfortunately this did not lead to the improvements we wanted, because there are still many locks and source of contention in the kernel. E.g., buffer recycling should be sharded too. SO_SHARDED is actually the source of most of the modifications in this repository. The other features do not depend on SO_SHARDED.
You can obtain a patch using git diff v5.1.5 and try your luck on applying to other kernel versions.
All features are built-in. Just compile the Kernel as you would normally do. A full tutorial for Ubuntu is available at https://wiki.ubuntu.com/Kernel/BuildYourOwnKernel. But these few steps should guide you through a faster compilation and installation if you use Ubuntu 18.04:
- Install dependencis with
sudo apt install build-essential libncurses5-dev flex bison openssl libssl-dev libelf-dev libudev-dev libpci-dev libiberty-dev autoconf - Configure your options, eg with you may copy the config file in /boot/configXXX to .config and then use "make olddefconfig" to upgrade the configuration to 5.1.5:
cp /boot/config-$(uname -r) .config && make olddefconfig make bzImage && make modulessudo make modules install && sudo make installsudo reboot
Options are used as any other socket option:
int migrate = 1;
setsockopt( fd, SOL_SOCKET, SO_AUTOMIGRATE, &migrate, sizeof(migrate) ))
See the iPerf2 modified version for a complete sample.
There are several guides for kernel developers and users. These guides can be rendered in a number of formats, like HTML and PDF. Please read Documentation/admin-guide/README.rst first.
In order to build the documentation, use make htmldocs or
make pdfdocs. The formatted documentation can also be read online at:
https://www.kernel.org/doc/html/latest/
There are various text files in the Documentation/ subdirectory, several of them using the Restructured Text markup notation.
Please read the Documentation/process/changes.rst file, as it contains the requirements for building and running the kernel, and information about the problems which may result by upgrading your kernel.