Xen performance on FreeBSD vs Linux

[Roger Pau Monné]

On Mon, Jan 06, 2020 at 12:43:51PM +0200, Stefan Parvu wrote:
> Hi,
> 
> How Xen hypervisor compares in terms of performance (guest) on FreeBSD vs Linux
> , using ZFS or UFS ?

There are several factors to take into account here.

On FreeBSD the hypervisor is built with clang, while on Linux it's
usually built with gcc, and hence different optimizations will be
used.

Also a FreeBSD dom0 can only work in PVH mode, which is faster for
certain operations like page table modifications, but it's slower for
others, like issuing hypercalls, when compared to a PV dom0.

I don't have figures at hand now, but guest creation is likely slower
on a FreeBSD PVH dom0 than on a Linux PV dom0, and that's because
hypercalls are more expensive on PVH than on PV (has nothing to do
whether Linux or FreeBSD is used).

> Are there any benchmarks or tests regarding this ?

I don't think so, but I think they will be useful if someone has the
time to perform them :).

Thanks, Roger.