Bad performance with Xen

[Agustin Lopez <Agustin.Lopez@xxxxx>]

Hello.


We are testing low performance in IO with the next command in Debian Buster 
(kernel 4.19.0-8-amd64) with Xen (4.11.4-pre)

       time for i in `dpkg -L ncurses-term | sort`; do if [ -f "$i" ]; then ls -ld  "$i"; fi; done | 
tr -s " "| cut -d" " -f5,9 >/dev/null


In all our Dom0s - DomUs  we are getting around 20 seconds.

In the same physical machines booting with Debian without Xen, we get 5-7 
seconds

In some KVM VMs in other server we are geting almost the same as physical.

(all in local Disks. XFS filesystems. Images of DomUs in raw format)


I have booted Xen with 4.8 y 4.4 releases with almost the same bad data.


Where could be the problem?

I think of is not normal this difference between DomUs and physical machine.


Every pointer will be welcomed.


Best regards,

Agustín