Monthly Archives: August 2012

First Xen Test Day, August 14th

After the success of Xen Document Days and with Xen 4.2 being close to release, we decided to trial Xen test Days. The first Xen Test Day will be on Tuesday, August 14th, on IRC freenode channel #xentest. The plan is to test Xen 4.2 RC2, whic h should be released shortly. You can find more information about Xen Test Days on:

What is a Xen Test Day?

Xen test days are all day IRC events, facilitated by members of the Xen community. The purpose of Xen Test Days is to

Security discussion poll

As promised, here is the poll for the security discussion. As a reminder, the purpose of this poll is mainly to see where people’s attitudes are with respect to the various options, so that we can move the discussion forward towards a conclusion. If you have any interested at all in the outcome, please make your voice heard.

The poll will not be secret. You may fill out the poll anonymously, but if you do, your vote will be given less weight (to avoid ballot stuffing). We don’t necessarily plan on publishing the individual poll responses, but we may do so if we think it would be helpful.

Because of the summer holidays, we will keep the poll open for two weeks; we will tabulate the results Monday, August 20.

The poll can be found here:

Thank you for your time.

3 weeks to XenSummit

It is time again for the XenSummit North America, which will start in 3 weeks. This year, XenSummit is conveniently co-located with CloudOpen and LinuxCon. If you use open source Xen, Huawei UVP, Oracle VM, XenServer, XenClient or other Xen derived products and want to see where the Xen open source project is heading, you should consider attending the 2012 Summit. If you are intending to build a Xen based cloud, XenSummit will also provide lots of great content.

XenSummit is a 2 day in-depth technical event that provides attendees with a chance to interact with and learn from contributors to projects and users of the open source Xen Hypervisor, Xen Cloud Platform and Xen ARM projects.

This year’s event will cover topics from Cloud Computing, Xen in embedded and mobile devices, Xen on ARM based Servers, Security, Xen and Linux, Xen and BSD, Xen case-studies, Xen and storage, latest Xen research as well as many others topics. The event features speakers from AMD, ARM, Broadcom, Bromium, the BSD Community, Cambridge University, Canonical, Calxeda, Citrix, The Flux Research Group, Galois, Huawei, Inktank, Intel, Locaweb, OnApp, Oracle, Rackspace Hosting and the University of Applied Sciences (HES) in Vaud.

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Linux PV Guest Performance Improvements

The Xen community achieved a major milestone last summer when all the necessary components for Xen dom0 support made it into the upstream kernel for the 3.0 release. However, during that process developers were focused on functionality, and not on performance. As a result a handful of performance regressions were introduced in pv-ops kernels compared to the classic kernels..

Recently I have started looking at performance aspects of pv-ops Linux by using xentrace and xenalyze (see George Dunlap’s presentation for an introduction) to compare the number and pattern of hypercalls between a classic 2.6.32 kernel and a 3.3 pvops one. I found a number of performance regressions which, luckily, are easily fixed or have minimal impact. The individual fixes are listed below.

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