Subject: Re: Bad performance of virtual disk driver
To: None <port-xen@NetBSD.org>
From: Matthias Scheler <tron@zhadum.de>
List: port-xen
Date: 05/03/2005 15:26:42
On Tue, May 03, 2005 at 02:34:56PM +0100, Matthias Scheler wrote:
> I've using the following setup:
>
> Hypervisor: Xen 2.0.5
> dom0: Linux 2.6.10
> domU: NetBSD 3.0_BETA (sources from 2005-04-28)
>
> The performace of the virtual disks is very bad ...
>
> # dd if=/dev/xbd1b of=/dev/null bs=1024k
> 512+0 records in
> 512+0 records out
> 536870912 bytes transferred in 331.800 secs (1618055 bytes/sec)
>
> ... compared to the performance in the Linux dom0:
>
> # dd if=/dev/vg/matthias-1swap of=/dev/null bs=1024k
> 512+0 records in
> 512+0 records out
> 536870912 bytes transferred in 15.469114 seconds (34705990 bytes/sec)
Performance in an unpriviliged Linux domain on the same machine ...
# dd if=/dev/sda2 of=/dev/null bs=1024k
200+0 records in
200+0 records out
209715200 bytes transferred in 20.675648 seconds (10143102 bytes/sec)
... is also slower than in the Linux dom0:
# dd if=/dev/vg/jds3swap of=/dev/null bs=1024k
200+0 records in
200+0 records out
209715200 bytes transferred in 5.931684 seconds (35355086 bytes/sec)
But here it is only by a factor of 3 and not 20.
Kind regards
--
Matthias Scheler http://scheler.de/~matthias/