From mboxrd@z Thu Jan  1 00:00:00 1970
From: "SourceForge.net" <noreply@sourceforge.net>
Subject: [ kvm-Bugs-1998355 ] IO Performance
Date: Thu, 18 Nov 2010 10:16:05 +0000
Message-ID: <E1PJ1XB-0004iN-0O@sfs-web-6.v29.ch3.sourceforge.com>
Mime-Version: 1.0
Content-Type: text/plain; charset="UTF-8"
To: noreply@sourceforge.net
Return-path: <kvm-owner@vger.kernel.org>
Received: from ch3.sourceforge.net ([216.34.181.60]:60301 "EHLO
	ch3.sourceforge.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org
	with ESMTP id S1756808Ab0KRLCA (ORCPT <rfc822;kvm@vger.kernel.org>);
	Thu, 18 Nov 2010 06:02:00 -0500
Sender: kvm-owner@vger.kernel.org
List-ID: <kvm.vger.kernel.org>

Bugs item #1998355, was opened at 2008-06-20 02:11
Message generated for change (Comment added) made by jessorensen
You can respond by visiting: 
https://sourceforge.net/tracker/?func=detail&atid=893831&aid=1998355&group_id=180599

Please note that this message will contain a full copy of the comment thread,
including the initial issue submission, for this request,
not just the latest update.
Category: None
Group: None
>Status: Closed
>Resolution: Out of Date
Priority: 5
Private: No
Submitted By: Joshua Rosen (bjrosen)
Assigned to: Nobody/Anonymous (nobody)
Summary: IO Performance 

Initial Comment:
Is there any way of mapping a host's directory into a KVM VM similar to VMware's Shared Folder feature?

I've been benchmarking the performance of NCVerilog under various VMs. The performance of KVM when using a virtual disk is excellent, in fact it's better than VMware Server or VMware Workstation, however if you use
an NFS mounted host directory the performance is unspeakably awful. An NFS mounted directory under VMware Server 2.0 (Beta 2) is also slow but it's still significantly better than KVM. Using a Shared Folder with VMware Workstation eliminates the IO bottleneck, the performance there is about the same as accessing a virtual disk.

The system that I did these benchmarks on is a 3GHz Core2 with 8G of RAM. VMware was running under CentOS5.1 with a 2.6.23.7 kernel. KVM is running on Fedora 9 with a 2.6.25.xx kernel. The Verilog simulation times for my test suite are as follows,

Native				06:34
VM Server 2, virtual disk	08:05
VM Server 2, NFS		18:37
VM Workstation, shared folder	08:14
KVM, Virtual disk		07:42
KVM, NFS			38:36


----------------------------------------------------------------------

>Comment By: Jes Sorensen (jessorensen)
Date: 2010-11-18 11:16

Message:
Per previous comment, bug is out of date.

There are a number of solutions in upstream and better performance. If you
still feel this is an issue, please feel free to open a new bug in
Launchpad.

Thanks,
Jes


----------------------------------------------------------------------

Comment By: Jes Sorensen (jessorensen)
Date: 2010-08-19 12:18

Message:
Hi,

Did this get resolved? If so would you mind closing this bug. If I don't
hear back, I
will assume it is fixed and close it at some point :)

Thanks,
Jes


----------------------------------------------------------------------

Comment By: Joshua Rosen (bjrosen)
Date: 2008-06-22 15:54

Message:
Logged In: YES 
user_id=39829
Originator: YES

I've tried the following command line, it brings up the VM but I can't
configure the NIC, there is an error message about vlan 0.

qemu-kvm -M pc -m 512 -smp 1 -monitor pty -net
nic,macaddr=a0:1e:37:84:b1:da,model=virtio  -boot c -hda /home/xen/panther
Warning: vlan 0 is not connected to host network

I've also tried the following, but the qemu-ifup command is missing an
argument

qemu-kvm -M pc -m 512 -smp 1 -monitor pty -net
nic,macaddr=a0:1e:37:84:b1:da,model=virtio -net
tap,script=/etc/xen/qemu-ifup -boot c -hda /home/xen/panther
config qemu network with xen bridge for  tap0
Incorrect number of arguments for command
Usage: brctl addif <bridge> <device>	add interface to bridge
char device redirected to /dev/pts/3

----------------------------------------------------------------------

Comment By: Dor Laor (thekozmo)
Date: 2008-06-22 08:08

Message:
Logged In: YES 
user_id=2124464
Originator: NO

Example cmdline:
./qemu/x86_64-softmmu/qemu-system-x86_64 -boot c -drive
file=/images/xpbase.qcow2,if=ide,cache=on,format=qcow2,boot=on -m 384  -net
nic,macaddr=a0:1e:37:84:b1:da,model=virtio -net
tap,script=/etc/kvm/qemu-ifup -snapshot

btw: you can use 'ps' to discover libvirt cmdline

----------------------------------------------------------------------

Comment By: Joshua Rosen (bjrosen)
Date: 2008-06-22 03:18

Message:
Logged In: YES 
user_id=39829
Originator: YES

How do I use virtio-net instead of virtio-blk?

I've been launching the VM using virt-manager which has no options. KVM
doesn't have a MAN page so I have no idea about how to launch the VM using
the CLI. Would you please give me specific step by step instructions.

Thanks,


----------------------------------------------------------------------

Comment By: Joshua Rosen (bjrosen)
Date: 2008-06-21 16:28

Message:
Logged In: YES 
user_id=39829
Originator: YES

How do I use virtio-net instead of virtio-blk?

I've been launching the VM using virt-manager which has no options. KVM
doesn't have a MAN page so I have no idea about how to launch the VM using
the CLI. Would you please give me specific step by step instructions.

Thanks,


----------------------------------------------------------------------

Comment By: Dor Laor (thekozmo)
Date: 2008-06-21 15:45

Message:
Logged In: YES 
user_id=2124464
Originator: NO

If you don't boot from virtio-blk there is no need for this
configuration.
Just use virtio-net in order to boost nfs accesses.

----------------------------------------------------------------------

Comment By: Joshua Rosen (bjrosen)
Date: 2008-06-21 01:29

Message:
Logged In: YES 
user_id=39829
Originator: YES

The instructions for setting up virtio are a little confusing. I have a
CentOS5 VM on Fedora 9. F9 uses the 2.6.25 kernel. 

The wiki says to edit /etc/initramfs-tools/modules however it doesn't say
whether this file is on the host or the guest. There is no
/etc/initramfs-tools directory on either. Would someone please clarify the
procedure for adding a virtio NIC on an F9 host.


----------------------------------------------------------------------

Comment By: Dor Laor (thekozmo)
Date: 2008-06-20 23:58

Message:
Logged In: YES 
user_id=2124464
Originator: NO

Did you use virtio nic when testing kvm with NFS?
If not, do try, it should boost your performance.

----------------------------------------------------------------------

You can respond by visiting: 
https://sourceforge.net/tracker/?func=detail&atid=893831&aid=1998355&group_id=180599