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

George Dunlap
The Paravirtualization Spectrum, part 1: The Ends of the Spectrum
Oct 23 2012

At XenSummit 2012 in San Diego, Mukesh Rathor from Oracle presented his work on a new virtualization mode, called “PVH”. Adding this mode, there are now a rather dizzying array of different terms thrown about — “HVM”, “PV”, “PVHVM”, “PVH” — what do they all mean? And why do we have so

Xen.org on Uservoice.com
Oct 15 2012

One of the issues in any software project can be the disconnect between what users want or would find useful, and the developers’ idea of what users want or would find useful, and Xen is no exception. To help address this issue, we are starting to experiment with a website

Disclosure process poll results
Aug 23 2012

Monday we closed the poll for the security discussion. Thank you everyone who participated! The process has not turned up a hidden option that everyone agreed on; however, it has helped find what I hope will be a “median” option which best addresses the concerns and desires as the community

Security discussion poll
Aug 06 2012

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

The Intel SYSRET privilege escalation
Jun 13 2012

The Xen Security team recently disclosed a vulnerability, Xen Security Advisory 7 (CVE-2012-0217), which would allow guest administrators to escalate to hypervisor-level privileges. The impact is much wider than Xen; many other operating systems seem to have the same vulnerability, including NetBSD, FreeBSD, some versions of Microsoft Windows (including Windows

Xen 4.2 preview: xl and pci pass-through
Jun 04 2012

One of the goals for the 4.2 release is for xl to have feature parity with xm for the most important functions. But along the way, we’ve also been adding a number of improvements to the interface as well. One of the ways in which xl has changed

Xen 4.2: cpupools
Apr 23 2012

Among the more unique features of Xen 4.2 is a feature called cpupools, designed and implemented by Jürgen Groß at Fujitsu. At its core it’s a simple idea, but one that allows it to be a flexible and powerful solution to a number of different problems. The

Xen 4.2: New scheduler parameters
Apr 10 2012

Xen 4.2 will contain two new scheduling parameters for the credit1 scheduler which significantly increase its confurability and performance for cloud-based workloads: timeslice_ms and ratelimit_us. This blog post describes what they do, and how to configure them for best performance. Timeslice The timeslice for the credit1 has

Xen Hackathon crazy idea: insmod xen
Sep 15 2011

One of the fun things about a hackathon is the chance to get everyone together in a room and just talk about crazy ideas you might try at some point in the future. One of the advantage that a certain competing virtualization technology has over Xen is that you don’

Linux 2.6.37: first upstream Linux kernel to work as Dom0
Jan 14 2011

by Stefano Stabellini Linux 2.6.37, released just few days ago, is the first upstream Linux kernel that can boot on Xen as Dom0: Linus pulled my “xen initial domain” patch series on the 28th of October and on the 5th of January the first Linux kernel was released

Xen Community Manager Search
Nov 22 2010

Quick update on the community manager search. We’ve interviewed a number of candidates, all of whom look very promising. We’re going to be discussing them soon, and hopefully sending out offers within a reasonable time frame after that. So stay tuned!

Xen Summit / Xen Directions Asia 2010
Oct 18 2010

As many of you know, XenSummit Asia 2010, originally planned for Nov 3-4 in Seoul, Korea, is being postponed. The current plan is to push back the event by about a month, and possibly expand it to include a user “XenDirections” track. Until we hire a new community Xen.org