Well then, thanks for the hint.. dmesg shows the following:

Jan 16 18:22:30 bsd10 kernel: xn0: <Virtual Network Interface> at device/vif/0 
on xenbusb_front0
Jan 16 18:22:30 bsd10 kernel: xn0: Ethernet address: 00:16:3e:df:1b:5a
Jan 16 18:22:30 bsd10 kernel: xenbusb_back0: <Xen Backend Devices> on xenstore0
Jan 16 18:22:30 bsd10 kernel: xn0: backend features: feature-sg feature-gso-tcp4
Jan 16 18:22:30 bsd10 kernel: xbd0: 8192MB <Virtual Block Device> at 
device/vbd/768 on xenbusb_front0
Jan 16 18:22:30 bsd10 kernel: xbd0: attaching as ada0
Jan 16 18:22:30 bsd10 kernel: xbd0: features: flush, write_barrier
Jan 16 18:22:30 bsd10 kernel: xbd0: synchronize cache commands enabled.

Now i did some tests with raw images and the disk performs very well (10-15% 
less than native throughput).

Is this a known problem or maybe specific to this constellation?

The Test System is running on a Haswell Intel Core i3 CPU (4310T) with an Intel 
H81 Chipset.

Cheers,
Sydney.

On 16.01.2014, at 18:06, Sydney Meyer <meyer.syd...@googlemail.com> wrote:

> No, the VMs are running on local LVM Volumes as Disk Backend.
> 
>> On 16 Jan 2014, at 17:59, Roger Pau Monné <roger....@citrix.com> wrote:
>> 
>>> On 16/01/14 17:41, Sydney Meyer wrote:
>>> Hello everyone,
>>> 
>>> does someone know how to check if the paravirtualized I/O drivers from Xen 
>>> are loaded/working in FreeBSD 10? To my understanding it isn't necessary 
>>> anymore to compile a custom kernel with PVHVM enabled, right? In 
>>> /var/log/messages/ I can see the XN* and XBD* devices and the network 
>>> performance is very good (saturated Gb) compared to qemu-emulated, but the 
>>> disk performance is not as well, infact, it is even slower than emulated 
>>> with qemu (0.10.2). I did some test with dd and bonnie++, turned caching on 
>>> the host off and tried to directly sync to disk, PVonHVM is averagely 15-20 
>>> % slower than QEMU at throughput. Both VM's are running on the same host on 
>>> a Xen 4.1 Hypervisor with QEMU 0.10.2 on a Debian Linux 3.2 Kernel as Dom0.
>> 
>> PV drivers will be used automatically if Xen is detected. You should see
>> something like this on dmesg:
>> 
>> xn0: <Virtual Network Interface> at device/vif/0 on xenbusb_front0
>> xn0: Ethernet address: 00:16:3e:47:d4:52
>> xenbusb_back0: <Xen Backend Devices> on xenstore0
>> xn0: backend features: feature-sg feature-gso-tcp4
>> xbd0: 20480MB <Virtual Block Device> at device/vbd/51712 on xenbusb_front0
>> xbd0: features: flush, write_barrier
>> xbd0: synchronize cache commands enabled.
>> 
>> Are you using a raw file as a disk?
>> 
>> Roger.
>> 

_______________________________________________
freebsd-virtualization@freebsd.org mailing list
http://lists.freebsd.org/mailman/listinfo/freebsd-virtualization
To unsubscribe, send any mail to 
"freebsd-virtualization-unsubscr...@freebsd.org"

Reply via email to