Linux Virtualization

Lies, statistics and benchmarks

Posted by Fraser Campbell Thu, 08 Mar 2007 23:56:00 GMT

VMware published a A Performance Comparison of Hypervisors at the end of January. Since the paper only discusses Windows I didn’t bother commenting – I don’t give two hoots about Windows.

Still the story is becoming amusing enough to warrant some study. Simon Crosby, Xensource CTO, recently published his thoughts the study:

All of XenSource’s commercial products match or beat ESX performance for Windows in all but a couple of benchmarks. This for a new product, and using the HVM feature set that has never been tuned. For Linux, we absolutely thrash ESX, which should come as no surprise. We’ll publish all of our results… just as soon as we get permission from VMware, that is.

Simon’s complete commentary is available in the Xensource blog here.

I would really have to agree with Simon, there are various commercial implementations of Xen (even if they aren’t allowed to be called that) and all will undoubtedly perform better than the older open source codebase that VMware did their comparison against.

Since VMware is comparing apples to oranges it reminds me a bit of the benchmarks I did a year ago with SuSE on Xen versus SuSE on ESX. Let’s just say embarrassing is not the word, joke might be the word but it sounds rather unprofessional – paravirtualization does help whether it’s just a paravirtualized network driver as in VMware’s windows benchmarks, or if it’s a completely paravirtualized kernel as in my SuSE on Xen tests.

Let’s hope that this evil policy of banning free and open benchmarking is lifted so that reasonable public discourse can take place without threat of lawsuit.

Posted in Xen, XenSource, VMware | no comments

Ulrich Drepper on hypervisors versus KVM

Posted by Fraser Campbell Tue, 27 Feb 2007 13:05:00 GMT

Ulrich Drepper is lead maintainer of the Linux C library (GNU libc), works for Red Hat and is well known in Linux circles – basically he is one smart cookie.

Last night he has posted a great article entitled Xensource/VMWare start sandbagging.

The article discusses the fact that Linux already has great support for NUMA, SMP, scheduling, hardware drivers, etc. My favorite “As for better scheduling with a hypervisor: that can only be a joke.”.

We can expect the marketing machines to crank out reams of verbage in the next 6 months but I trust Mr. Drepper more than I would trust anything I see coming from the corporate presses.

Linux as the hypervisor just makes sense. Jeff Dike has been pushing the idea for years with UML and UML continues to move forward.

The only slight beef (or question) I have with KVM is why has it diverged from QEMU? More specifically KVM relies on QEMU for it’s device emulation but it also requires hardware virtualization. Now that QEMU’s kernel accelerator is open source could KVM and QEMU not be merged back together to give us one high performing solution that would support both VT and non-VT capable hardware?

Posted in Xen, XenSource, QEMU, VMware, KVM | 2 comments