
Performance benchmarks: KVM vs. Xen - lelf
https://major.io/2014/06/22/performance-benchmarks-kvm-vs-xen/
======
arielweisberg
I don't see a benchmark of network IO, especially small packet performance, or
heavy random IO workloads on SSD?

If those are the kinds of apps you want to run that is great, but I would need
to see more to get an idea of how they compare for frontend, caching, content,
or database serving.

The difference I see between virtualization configurations for things like
small packet performance is dramatic even within the same hypervisor.

------
drostie
That's actually really interesting. I wanted at one point to run Joyent's
SmartOS ([http://smartos.org/](http://smartos.org/)) on a desktop, since it
seems like I live my work-life in VMware anyways. I'd like to know what
VMware's processor cost is, because I've definitely noticed it indirectly when
trying to do the same thing both inside and outside the VM. Let's take my last
example: a Python script which searches a large graph to find out how many
paths there are with N edges or fewer. It turned out to save a couple hours of
running time to install Python on Windows and then run on Windows than to run
on Linux in the VM, and I may be wrong, but I don't think that the Windows
version of Python is magically faster than the Linux one.

I also haven't figured out how to get VMware to let me do OpenCL stuff, which
has occasionally been a headache when some library does exactly what I want to
do, but does it with OpenCL. The hope would be that bare-metal hypervisors
would be a little more transparent.

But yeah, 2% is great news. I don't even consider this a "win" against Xen
necessarily; I think they're both showing that they're much more competitive
than I thought they'd be.

------
lazyant
"Xen fell within 2.5% of bare metal performance in three out of ten tests but
often had a variance of up to 5-7%"

Happy to see that I had it bang on
[https://news.ycombinator.com/item?id=8285851](https://news.ycombinator.com/item?id=8285851)

------
imaginenore
Add units to the table, it's absolutely not clear if higher=better or the
opposite.

------
bstx
Any KVM vs. Xen PV benchmarks? The Xen (PV)HVM case isn't that interesting.

