WARNING - OLD ARCHIVES

This is an archived copy of the Xen.org mailing list, which we have preserved to ensure that existing links to archives are not broken. The live archive, which contains the latest emails, can be found at http://lists.xen.org/
   
 
 
Xen 
 
Home Products Support Community News
 
   
 

xen-users

Re: [Xen-users] Exporting a PCI Device

To: Joris Dobbelsteen <Joris@xxxxxxxxxxxxxxxxxxxxx>
Subject: Re: [Xen-users] Exporting a PCI Device
From: Jan Kalcic <jandot@xxxxxxxxxxxxxx>
Date: Tue, 19 Feb 2008 11:30:35 +0100
Cc: deshantm@xxxxxxxxx, xen-users@xxxxxxxxxxxxxxxxxxx
Delivery-date: Tue, 19 Feb 2008 02:29:36 -0800
Dkim-signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=googlemail.com; s=gamma; h=domainkey-signature:received:received:message-id:date:from:user-agent:mime-version:to:cc:subject:references:in-reply-to:content-type:content-transfer-encoding; bh=QOK1qkbaY7+YjUljMqkS0fKuDL/iHz3Xr3ZDQ+cjahE=; b=p6FwpFkcs9WY5SNwt9P+pM2MDPagIRmlXDu5iNVCbTn7tPHLNm5txUKiX+Nm350TTKAYmJAo0eLHetUrT86/eo8rJsgfLN8K2KbIbHLgDbY6MD3lWZAPddcXeVjE7Xq88L0DYv3VpW8xdAqCpIJ/PJ+fyAB08sQdKBWI7a4ruS8=
Domainkey-signature: a=rsa-sha1; c=nofws; d=googlemail.com; s=gamma; h=message-id:date:from:user-agent:mime-version:to:cc:subject:references:in-reply-to:content-type:content-transfer-encoding; b=lV27bRDKYcEGsA0/4C5jKnrYP7gkykLPMKHca/zUSoBPVlPqOHAG1JJQwZL4dqF/pPPIWNtcpVPjtSSJhEZ3laVFrMbs4J5lvBZZ0UavLv3upG0lfI0UcNGFJkaDmatD6sZhsPgGdBWf85iD/eLg4BobgoUTDZByaM6LsGwgSl8=
Envelope-to: www-data@xxxxxxxxxxxxxxxxxx
In-reply-to: <E4953B65D9E5054AA6C227B410C56AA9C37E@xxxxxxxxxxxxxxxxxxxxxxx>
List-help: <mailto:xen-users-request@lists.xensource.com?subject=help>
List-id: Xen user discussion <xen-users.lists.xensource.com>
List-post: <mailto:xen-users@lists.xensource.com>
List-subscribe: <http://lists.xensource.com/cgi-bin/mailman/listinfo/xen-users>, <mailto:xen-users-request@lists.xensource.com?subject=subscribe>
List-unsubscribe: <http://lists.xensource.com/cgi-bin/mailman/listinfo/xen-users>, <mailto:xen-users-request@lists.xensource.com?subject=unsubscribe>
References: <47B8C482.5050600@xxxxxxxxxxxxxx><1e16a9ed0802171801n591a4949r4ee5e362c2f80f05@xxxxxxxxxxxxxx> <47B965A9.4040300@xxxxxxxxxxxxxx> <E4953B65D9E5054AA6C227B410C56AA9C379@xxxxxxxxxxxxxxxxxxxxxxx> <47BA0A48.9080004@xxxxxxxxxxxxxx> <E4953B65D9E5054AA6C227B410C56AA9C37E@xxxxxxxxxxxxxxxxxxxxxxx>
Sender: xen-users-bounces@xxxxxxxxxxxxxxxxxxx
User-agent: Thunderbird 2.0.0.9 (X11/20070801)
Joris Dobbelsteen wrote:
>> -----Original Message-----
>> From: Jan Kalcic [mailto:jandot@xxxxxxxxxxxxxx] 
>> Sent: Monday, 18 February 2008 23:44
>> To: Joris Dobbelsteen
>> Cc: deshantm@xxxxxxxxx; xen-users@xxxxxxxxxxxxxxxxxxx
>> Subject: Re: [Xen-users] Exporting a PCI Device
>>
>>     
> [snip]
>   
>> I did some test and actually it's quite slow both in reading 
>> and in writing. Roughly 50% as Block Device attacched to the domU.
>> It reduces complexity but too much is lost in performance.
>>     
>
> For some odd reason I'm seeing a similar things on my box with attached
> RAID-0 & LVM. The domU only reaches 50%. I don't know the cause, I only
> heared comments that it had todo with LVM oddities that RAID seemed to
> aggrivate. Nevertheless the dom0 reaches full speed.
>
> Coincidence or a sign of deeper trouble?
>
> My setup is just some standard (cheap) SATA disks, it's a personal
> system. It does run Xen 3.1.2, the 2.6.20 kernel on the domU and the
> Debian Etch 2.6.18 kernels on the guests. Tests where with Bonnie++
> (that's part of debian etch).
>
> To rule out the virtual block device playing tricks I would try to see
> what happens with a slower disk on the SAN and even with a local disk
> (in the system itself).
>
> - Joris
>
>
>   
Hi Joris,

I did some test on the local disk (software RAID) of another system just
to have an idea about performance. There is a bit lost in performance,
dom0 tends to be a little quicker even if the difference is not so big
to be problematic. Differently was on the other system with SAN which I
could not test. I'll do soon and I'll let you know. The following is the
output of the test I did.

What do you mean when you say "deeper trouble"? Do you refer to Xen code
or something about the infrastructure configuration?

Thanks,
Jan


domU

# dd if=/dev/zero of=/mnt/test count=1000 bs=1M
1000+0 records in
1000+0 records out
1048576000 bytes (1.0 GB) copied, 18.7752 seconds, 55.8 MB/s

1000+0 records in
1000+0 records out
1048576000 bytes (1.0 GB) copied, 12.395 seconds, 84.6 MB/s

1000+0 records in
1000+0 records out
1048576000 bytes (1.0 GB) copied, 18.1577 seconds, 57.7 MB/s


# hdparm -t /dev/sdd1 (three times)

/dev/sdd1:
 Timing buffered disk reads:  116 MB in  3.00 seconds =  38.62 MB/sec

/dev/sdd1:
 Timing buffered disk reads:  156 MB in  3.01 seconds =  51.80 MB/sec

/dev/sdd1:
 Timing buffered disk reads:  148 MB in  3.03 seconds =  48.85 MB/sec
-------------------------------------------------------------
dom0

# dd if=/dev/zero of=/data/test count=1000 bs=1M (three times)
1000+0 records in
1000+0 records out
1048576000 bytes (1.0 GB) copied, 13.2577 seconds, 79.1 MB/s

1000+0 records in
1000+0 records out
1048576000 bytes (1.0 GB) copied, 18.3124 seconds, 57.3 MB/s

1000+0 records in
1000+0 records out
1048576000 bytes (1.0 GB) copied, 12.244 seconds, 85.6 MB/s

# hdparm -t /dev/md3

/dev/md3:
 Timing buffered disk reads:  164 MB in  3.02 seconds =  54.37 MB/sec

/dev/md3:
 Timing buffered disk reads:  172 MB in  3.01 seconds =  57.21 MB/sec

/dev/md3:
 Timing buffered disk reads:  180 MB in  3.01 seconds =  59.85 MB/sec
                                                         



_______________________________________________
Xen-users mailing list
Xen-users@xxxxxxxxxxxxxxxxxxx
http://lists.xensource.com/xen-users