Xen 4.3.0 released!

Xenproject.org is pleased to announce the release of Xen 4.3.0. The release is available from the download page:

Xen 4.3 is the work of just over 9 months of development, with 1362 changesets containing changes to over 136128 lines of code, made by 90 individuals from 27 different organizations and 25 unaffiliated individual developers.

Xen 4.3 is also the first release made with using the roadmap to track what people were doing and aim for what to try to get into this release, as well as the first release to have consistent Xen test days. This, combined with the increased number of contributors, should make this one of the best Xen releases so far. Read on for more information.

New Features

Probably the biggest single feature of this release is the experimental support for ARM virtualization, both 32-bit and 64-bit variants. The 32-bit port of Xen boots on ARMv7 Fast Models, the Cortex A15 Versatile Express platform and the Arndale board (equipped with the Exynos5 SoC by Samsung). It can boot dom0, create other virtual machines and it supports all the basic virtual machine lifecycle operations. Hardware is not yet available for 64-bit ARM processors yet, but Xen is running well in 64-bit mode on AEMv8 Real-time System Models by ARM.

The next headline feature is NUMA-aware scheduling. The scheduler now knows on which nodes a VM’s memory resides, and will preferentially run them there, while still allowing them to run elsewhere if the system is too busy. More on NUMA affinity can be found in Dario Faggioli’s blog on the subject.

Another cool new feature is support for openvswitch as a bridging mechanism. Hot-plug scripts for openvswitch are now included in the Xen tree, so setting it up is straightforward and reliable. See Openvswitch setup for more details.

Another big change is that we will be switching the default qemu from our old qemu fork (affectionately called qemu-traditional) to qemu-xen. qemu-xen will be based on a recent release of the upstream qemu project, plus a small number of patches, mostly back-ports from upstream of fixes and new features. qemu-traditional will still be available.

There are many more improvements and changes under the hood. For a more complete list, see the Xen 4.3 feature list.

Thanks

Contributions were made to this release from 90 individuals working for 27 different organizations, not counting contributions made to other important components such as qemu, Linux, the BSDs, and so on.

The diagram below shows organizations which contributed more than 1% in lines of code to the Xen 4.3 release. Several items in the diagram describe groups of people or organizations: (Individual) covers contributions by individuals whose affiliation is unknown, (Other) covers contributions by commercial organizations which did not go above 1% individually and (Academia, Other) covers contributions by Universities which did not go above 1% individually.

Xen 4.3 contribution stats

I did also want to list the top 20 contributors to Xen 4.3 (in terms of commits/and lines of code). These are: Jan Beulich(266/11148), Ian Campbell(225/62548), Stefano Stabellini(80/3332), Daniel De Graaf(68/5444), Ian Jackson(65/2170), Julien Grall(56/3682), Olaf Hering(40/391), Tim Deegan(35/1814), Dongxiao Xu(33/853), George Dunlap(32/578), Keir Fraser(31/8881), Konrad Rzeszutek Wilk(31/440), Matthew Fioravante(29/19322), Andrew Cooper(24/369), Roger Pau Monne(24/660), Anthony PERARD(23/1017), Christoph Egger(23/1298), Dario Faggioli(23/1306), Boris Ostrovsky(16/481), and Daniel Kiper(13/70).

For a complete breakdown see the Acknowledgement page. A big thank you again!

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About George Dunlap

I received my PhD from the University of Michigan in December 2006. I joined XenSource in May of 2006. I've been working on analyzing performance in the Xen hypervisor. I'm currently working on a new scheduler.