Virtio and WinXP (disk drivers)

Virtio and WinXP (disk drivers)

[Alpár Török]

Hi,

First of all please allow me to salute the community since this is my
first post.

Now my problem. I have been using KVM to conduct tests for various
software  on windows, so far it worked out just fine. I use savevm and
loadvm to assure that the VM is in the same state for each test. I do
a savevm manually, then start the automatic tests.

Lately i was trying to optimize parts of my tests, to increase the throughput.

First the network I/O was slow with the default device, and i needed
to copy some files to the VM for each test. The virtio network driver
was fast, but with my bridge networking, on Win XP, after starting the
VM with loadvm. This isn't such a big issue since i then started using
e1000 device, and speed increased. I am not sure just how much would
virtio be faster, so the question remains : Doesn't virtio work with
loadvm/savevm, or (most probably) am i doing something wrong?

The second issue, even a greather one, is disk access speed in the VM.
Again i have looked at virtio, but it seems that there is no Win
direver. Is that so? What can i do to improove disk access
performance?

The final issue isn't related to performance. With the e1000 device,
accessing or writing files  on a samba share from the host failes
saying that the file doesn't exists, (the file exists, i am sure).
This doesn't happen all that often, less than 1% of the time, but it's
rather anolying because it influences the tests. it seems to be happen
randomly, i caoudm't identify a factor that might be causing it.

Thank you in advance for your advices.

--
Alpar Torok

Re: Virtio and WinXP (disk drivers)

[Dor Laor]

Alpár Török wrote:
> Hi,
>
> First of all please allow me to salute the community since this is my
> first post.
>   
Congratulations, hoping for the next ones :)
> Now my problem. I have been using KVM to conduct tests for various
> software  on windows, so far it worked out just fine. I use savevm and
> loadvm to assure that the VM is in the same state for each test. I do
> a savevm manually, then start the automatic tests.
>
> Lately i was trying to optimize parts of my tests, to increase the throughput.
>
> First the network I/O was slow with the default device, and i needed
> to copy some files to the VM for each test. The virtio network driver
> was fast, but with my bridge networking, on Win XP, after starting the
> VM with loadvm. This isn't such a big issue since i then started using
> e1000 device, and speed increased. I am not sure just how much would
> virtio be faster, so the question remains : Doesn't virtio work with
> loadvm/savevm, or (most probably) am i doing something wrong?
>   
Indeed virtio performs better than e1000.
It should work, please provide host kernel version, kvm version, virtio 
net version and
windows guest type. Also the cmdline and monitor command will help.

> The second issue, even a greather one, is disk access speed in the VM.
> Again i have looked at virtio, but it seems that there is no Win
> direver. Is that so? What can i do to improove disk access
> performance?
>
>   
We have beta code for windows pv block. We plan to publish them as soon
they will be rock stable. Scsi emulation also exist but might not be 
100% stable.
> The final issue isn't related to performance. With the e1000 device,
> accessing or writing files  on a samba share from the host failes
> saying that the file doesn't exists, (the file exists, i am sure).
> This doesn't happen all that often, less than 1% of the time, but it's
> rather anolying because it influences the tests. it seems to be happen
> randomly, i caoudm't identify a factor that might be causing it.
>
>   
Seems like a samba related bug and not necessarily network bug.
> Thank you in advance for your advices.
>
> --
> Alpar Torok
> --
> To unsubscribe from this list: send the line "unsubscribe kvm" in
> the body of a message to majordomo@vger.kernel.org
> More majordomo info at  http://vger.kernel.org/majordomo-info.html
>   

Re: Virtio and WinXP (disk drivers)

[Alpár Török]

2009/2/25 Dor Laor <dlaor@redhat.com>:
> Alpár Török wrote:
>>
>> Hi,
>>
>> First of all please allow me to salute the community since this is my
>> first post.
>>
>
> Congratulations, hoping for the next ones :)
>>
>> Now my problem. I have been using KVM to conduct tests for various
>> software  on windows, so far it worked out just fine. I use savevm and
>> loadvm to assure that the VM is in the same state for each test. I do
>> a savevm manually, then start the automatic tests.
>>
>> Lately i was trying to optimize parts of my tests, to increase the
>> throughput.
>>
>> First the network I/O was slow with the default device, and i needed
>> to copy some files to the VM for each test. The virtio network driver
>> was fast, but with my bridge networking, on Win XP, after starting the
>> VM with loadvm. This isn't such a big issue since i then started using
>> e1000 device, and speed increased. I am not sure just how much would
>> virtio be faster, so the question remains : Doesn't virtio work with
>> loadvm/savevm, or (most probably) am i doing something wrong?
>>
>
> Indeed virtio performs better than e1000.
> It should work, please provide host kernel version, kvm version, virtio net
> version and
> windows guest type. Also the cmdline and monitor command will help.
kernel is 2.6.25.16-0.1-default of openSuse 11.0
KVM version is 63-31.1 (also shipped with the distribution)
I don't know what version i have tried beafore, i tried to repeat the
scenario, and coudn't even install the latest version i have just
downloaded (5.1.2008.1229) , and failes with : device coudn't be
started (code=10) , it's strange.
The guest is Xindows Xp SP2
the  command line is :  -net nic,ifname=virtio -net tap,tap0 -m 256
-loadvm state

here is my small script that initializes the network (please note that
i need the machines to be isolated from the external world)

vconfig add eth0 2
brctl addbr br0
brctl addif br0 eth0.2
for ((i=0; i < 2 ; i++)); do
   echo -n "Setting up  $i"
   tunctl -u 1 -t tap$i
   brctl addif br0 tap$i
   ifconfig tap$i up promisc
done
ifconfig br0 10.0.1.1 netmask 255.255.255.0

Changing parts of this setup can also make networking not work after
savevm / loadvm  , not even with e1000, in some cases, the network
stops working only  after the host is restarted (the network
configuration re - created).
>
>> The second issue, even a greather one, is disk access speed in the VM.
>> Again i have looked at virtio, but it seems that there is no Win
>> direver. Is that so? What can i do to improove disk access
>> performance?
>>
>>
>
> We have beta code for windows pv block. We plan to publish them as soon
> they will be rock stable. Scsi emulation also exist but might not be 100%
> stable.

Where can i find code or binaries? In my case. If it speeds things up,
more than it makes them crash, i won't mind using it, and could
probably get you some debug data on those crashes, or help in other
similar ways.

>>
>> The final issue isn't related to performance. With the e1000 device,
>> accessing or writing files  on a samba share from the host failes
>> saying that the file doesn't exists, (the file exists, i am sure).
>> This doesn't happen all that often, less than 1% of the time, but it's
>> rather anolying because it influences the tests. it seems to be happen
>> randomly, i caoudm't identify a factor that might be causing it.
>>
>>
>
> Seems like a samba related bug and not necessarily network bug.

any advice on how could i gather debugging information? I must be able
to include  this into my test cases, because i can't reproduce it by
hand, i have to trap the problem, when it happens.

>>
>> Thank you in advance for your advices.
>>
>> --
>> Alpar Torok
>> --
>> To unsubscribe from this list: send the line "unsubscribe kvm" in
>> the body of a message to majordomo@vger.kernel.org
>> More majordomo info at  http://vger.kernel.org/majordomo-info.html
>>
>
>



-- 
Alpar Torok

Re: Virtio and WinXP (disk drivers)

[Tomasz Chmielewski]

Alpár Török schrieb:

>> Indeed virtio performs better than e1000.
>> It should work, please provide host kernel version, kvm version, virtio net
>> version and
>> windows guest type. Also the cmdline and monitor command will help.
> kernel is 2.6.25.16-0.1-default of openSuse 11.0
> KVM version is 63-31.1 (also shipped with the distribution)

This is pretty ancient version - could you try kvm-84 to see if it 
solves your problems?



-- 
Tomasz Chmielewski
http://wpkg.org

Re: Virtio and WinXP (disk drivers)

[Alpár Török]

2009/2/25 Tomasz Chmielewski <mangoo@wpkg.org>:
> Alpár Török schrieb:
>
>>> Indeed virtio performs better than e1000.
>>> It should work, please provide host kernel version, kvm version, virtio
>>> net
>>> version and
>>> windows guest type. Also the cmdline and monitor command will help.
>>
>> kernel is 2.6.25.16-0.1-default of openSuse 11.0
>> KVM version is 63-31.1 (also shipped with the distribution)
>
> This is pretty ancient version - could you try kvm-84 to see if it solves
> your problems?

Yes, just to see if it works is not a problem. But i have many
machines, compiling for each of them would be unpractical, perhaps i
can make a new kernel rpm and install that for the other VMs, with the
latest KVM compiled in, if there's no other option i will try that, to
see if it solves the problems. Is there anything else that slipped my
mind, that would allow me to update kvm on all machines? I knew that
the version shipped with the distribution is old, but i went with it
for convenience of installation .

>
>
>
> --
> Tomasz Chmielewski
> http://wpkg.org
>
>



-- 
Alpar Torok

Re: Virtio and WinXP (disk drivers)

[Tomasz Chmielewski]

Alpár Török schrieb:
> 2009/2/25 Tomasz Chmielewski <mangoo@wpkg.org>:
>> Alpár Török schrieb:
>>
>>>> Indeed virtio performs better than e1000.
>>>> It should work, please provide host kernel version, kvm version, virtio
>>>> net
>>>> version and
>>>> windows guest type. Also the cmdline and monitor command will help.
>>> kernel is 2.6.25.16-0.1-default of openSuse 11.0
>>> KVM version is 63-31.1 (also shipped with the distribution)
>> This is pretty ancient version - could you try kvm-84 to see if it solves
>> your problems?
> 
> Yes, just to see if it works is not a problem. But i have many
> machines, compiling for each of them would be unpractical, perhaps i
> can make a new kernel rpm and install that for the other VMs, with the
> latest KVM compiled in, if there's no other option i will try that, to
> see if it solves the problems. Is there anything else that slipped my
> mind, that would allow me to update kvm on all machines? I knew that
> the version shipped with the distribution is old, but i went with it
> for convenience of installation .

If you don't want to compile a new kernel and make a package.

You can compile KVM to work with your old kernel.

Then, distribute kernel modules (3 files) and kvm/qemu binary (4th file) 
with rsync, done.
Still, you will have to stop virtual machines, remove/insert kvm 
modules, start the guests.

-- 
Tomasz Chmielewski
http://wpkg.org

Re: Virtio and WinXP (disk drivers)

[Alpár Török]

2009/2/25 Tomasz Chmielewski <mangoo@wpkg.org>:
> Alpár Török schrieb:
>>
>> 2009/2/25 Tomasz Chmielewski <mangoo@wpkg.org>:
>>>
>>> Alpár Török schrieb:
>>>
>>>>> Indeed virtio performs better than e1000.
>>>>> It should work, please provide host kernel version, kvm version, virtio
>>>>> net
>>>>> version and
>>>>> windows guest type. Also the cmdline and monitor command will help.
>>>>
>>>> kernel is 2.6.25.16-0.1-default of openSuse 11.0
>>>> KVM version is 63-31.1 (also shipped with the distribution)
>>>
>>> This is pretty ancient version - could you try kvm-84 to see if it solves
>>> your problems?
>>
>> Yes, just to see if it works is not a problem. But i have many
>> machines, compiling for each of them would be unpractical, perhaps i
>> can make a new kernel rpm and install that for the other VMs, with the
>> latest KVM compiled in, if there's no other option i will try that, to
>> see if it solves the problems. Is there anything else that slipped my
>> mind, that would allow me to update kvm on all machines? I knew that
>> the version shipped with the distribution is old, but i went with it
>> for convenience of installation .
>
> If you don't want to compile a new kernel and make a package.
>
> You can compile KVM to work with your old kernel.
>
> Then, distribute kernel modules (3 files) and kvm/qemu binary (4th file)
> with rsync, done.
> Still, you will have to stop virtual machines, remove/insert kvm modules,
> start the guests.

Stopping guests isn't a problem. i will try this on one machine, to
see if there are any improvements and post back.

On a second thought. Where can i find the pv block drivers for XP ?

>
> --
> Tomasz Chmielewski
> http://wpkg.org
>



-- 
Alpar Torok

Re: Virtio and WinXP (disk drivers)

[Dor Laor]

Alpár Török wrote:
> 2009/2/25 Tomasz Chmielewski <mangoo@wpkg.org>:
>   
>> Alpár Török schrieb:
>>     
>>> 2009/2/25 Tomasz Chmielewski <mangoo@wpkg.org>:
>>>       
>>>> Alpár Török schrieb:
>>>>
>>>>         
>>>>>> Indeed virtio performs better than e1000.
>>>>>> It should work, please provide host kernel version, kvm version, virtio
>>>>>> net
>>>>>> version and
>>>>>> windows guest type. Also the cmdline and monitor command will help.
>>>>>>             
>>>>> kernel is 2.6.25.16-0.1-default of openSuse 11.0
>>>>> KVM version is 63-31.1 (also shipped with the distribution)
>>>>>           
>>>> This is pretty ancient version - could you try kvm-84 to see if it solves
>>>> your problems?
>>>>         
>>> Yes, just to see if it works is not a problem. But i have many
>>> machines, compiling for each of them would be unpractical, perhaps i
>>> can make a new kernel rpm and install that for the other VMs, with the
>>> latest KVM compiled in, if there's no other option i will try that, to
>>> see if it solves the problems. Is there anything else that slipped my
>>> mind, that would allow me to update kvm on all machines? I knew that
>>> the version shipped with the distribution is old, but i went with it
>>> for convenience of installation .
>>>       
>> If you don't want to compile a new kernel and make a package.
>>
>> You can compile KVM to work with your old kernel.
>>
>> Then, distribute kernel modules (3 files) and kvm/qemu binary (4th file)
>> with rsync, done.
>> Still, you will have to stop virtual machines, remove/insert kvm modules,
>> start the guests.
>>     
>
> Stopping guests isn't a problem. i will try this on one machine, to
> see if there are any improvements and post back.
>
> On a second thought. Where can i find the pv block drivers for XP ?
>
>   
Currently we did not publish the drivers yet. We do plan to do so soon.
Nevertheless, the primary focus in first for all the win2k3, wink8 flavors
and only then for XP (it should be a problem anyway).

Do you have savevm/loadvm issues with virtio and latest kvm (84)?
>> --
>> Tomasz Chmielewski
>> http://wpkg.org
>>
>>     
>
>
>
>