Re: [CentOS-virt] performance differences between kvm/xen

[Todd Deshane]

Hi Grant,

On Wed, Oct 27, 2010 at 11:00 AM, Grant McWilliams
 wrote:
> Todd, I think there's more than one way to look at this as well. As Xen
> becomes more of a product and less of an installable package
> it will probably have to be profiled as a product.

The XCP devs hope that XCP will eventually be available via a package
install (for example something similar to yum install xcp).

> Say benchmark XCP on
> particular hardware and benchmark RHEL KVM on the same hardware and ESX as
> well.
> It makes sense to benchmark a XEN kernel and a KVM kernel if we have that
> flexibility but that's starting to shrink. Another test that I don't think
> is THAT important anymore is tesing Xen with and without pvops kernels.
> There were some rumors going around that the old 2.6.18 kernel was faster
> than the new pvops. I was going to put together tests and never got to it.
> Not that it makes any difference in the future because the old kernel is
> fast going
> away.
>

Yeah the old one is going away, comparing the forward port kernel (for
example from OpenSUSE) to the new pv_ops one is what we will want to
do. The pv_ops one may be better or worse under certain loads, but
unless we test, how will we know? Once we can demonstrate it, the
pv_ops kernel can be improved as needed too.

> What I'd like to have is a standardized test with a way of multiple people
> uploading it and comparing results so we can run it on as many systems as
> possible.
> Data correlation could then be done on the data. Currently we have one test
> over here and another over there and the tests never seem to be updated or
> even
> run again to verify results. Maybe none of it matters as the hypervisor
> becomes inconsequential.
>

Great, yes that is what research at Clarkson University tried to do.
As far as I know no one at Clarkson is actively working on it though.
I will check with them when I get a chance though.

> I'm going to look at the tests you've done as soon as time permits.

What we completed were some basic things. There is still more to test.

Thanks,
Todd

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Re: [CentOS-virt] performance differences between kvm/xen

[Todd Deshane]

On Tue, Oct 26, 2010 at 4:15 PM, Eric Searcy  wrote:
> On Oct 25, 2010, at 8:14 AM, Todd Deshane wrote:
>
>> I was also going to mention that we should look at scalability and
>> performance isolation.
>> Some references and previous studies here:
>>
>> http://todddeshane.net/research/Xen_versus_KVM_20080623.pdf
>> http://clarkson.edu/~jnm/publications/isolation_ExpCS_FINALSUBMISSION.pdf
>> http://clarkson.edu/~jnm/publications/freenix04-clark.pdf
>
> I only got as far as the top one.  One concern: the nestled comment "We 
> believe that KVM may have performed better than Xen in terms of I/O due to 
> disk caching" makes me skeptical of the value of the results if this wasn't 
> taken into consideration (in other words I think it is a much bigger problem 
> than the aforementioned comment gives credit to, such that it ought to be at 
> least addressed in the concluding remarks) ... for instance if my VM 
> load-outs use all but ~384M of total memory (that being the amount I leave to 
> the host, most of it used) then there's not going to be much extra RAM for 
> memory cache/buffers with on the host side (depending greatly on what 
> vm.swappiness camp you are in).  Based on the author's result output [1] 
> (since the VM parameters aren't given in the paper), as relates to a 
> disk-intensive test they in effect gave 2G potential caching to Xen but ~4G 
> to KVM.  Based at least on the amount of free memory on my Xen/KVM hosts I 
> don't think this "host memor
>  y cache bias" can be assumed to be a bonus trait that would normally be 
> present for KVM.  (And of course a cache bias would be even more noticeable 
> in the 256MB Phoronix test and in the 4x128M isolation tests [2] ...)
>
> [1] 
> http://web2.clarkson.edu/projects/virtualization/benchvm/results/performance/
> [2] 
> http://web2.clarkson.edu/projects/virtualization/benchvm/results/isolation/xen/memory/specweb1/SPECweb_Support.20080614-100931.html
>
> BTW, I do realize you're pointing out that we should look at scalability and 
> isolation, and here I am just giving critical feedback on a 3 year old paper 
> ... yes you're right those are important!  I just want to make sure the tests 
> are fair ;-)
>

These are old tests now and not necessarily perfect, but they were Xen
and KVM on the same kernel. KVM very early on and not necessarily in
its best light. The Xen dom0/domU kernel was also not the best light
for Xen. The point was to try to compare them on the same kernel. Xen
and KVM on the same kernel has happened in the form of OpenSUSE's
forward port of the Xen dom0 kernel with KVM that is already in
mainline. The pv_ops kernel is not fully mainline, but is getting
close. Some distros now have Xen dom0 kernels based on the pv_ops
kernel, which could also run KVM.

In any case, some updated numbers would be very welcome. And yes,
taking scalability, performance isolation, and other factors into
account is important.

I have been involved in quite a few performance studies over the years
and I will try to give advice and help as I can.

On Tue, Oct 26, 2010 at 2:38 PM, Grant McWilliams
 wrote:
> So you've already done a lot of this then Todd? Should we just be making a 
> standardized test out of your work?

At Clarkson, we tried to build a standardized tool called benchvm as a
standard, but it has been stuck in an alpha state for awhile
http://code.google.com/p/benchvm/

I can dig up the rejected academic paper on the benchvm if people are
interested, feel free to email me privately.

I wonder if using things like puppet, the phoronix test suite, etc.
are a simpler way to go? I guess it all depends on how general a
benchmarking tool is needed.

Thanks,
Todd

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Re: [CentOS-virt] performance differences between kvm/xen

[Eric Searcy]

On Oct 25, 2010, at 8:14 AM, Todd Deshane wrote:

> I was also going to mention that we should look at scalability and
> performance isolation.
> Some references and previous studies here:
> 
> http://todddeshane.net/research/Xen_versus_KVM_20080623.pdf
> http://clarkson.edu/~jnm/publications/isolation_ExpCS_FINALSUBMISSION.pdf
> http://clarkson.edu/~jnm/publications/freenix04-clark.pdf

I only got as far as the top one.  One concern: the nestled comment "We believe 
that KVM may have performed better than Xen in terms of I/O due to disk 
caching" makes me skeptical of the value of the results if this wasn't taken 
into consideration (in other words I think it is a much bigger problem than the 
aforementioned comment gives credit to, such that it ought to be at least 
addressed in the concluding remarks) ... for instance if my VM load-outs use 
all but ~384M of total memory (that being the amount I leave to the host, most 
of it used) then there's not going to be much extra RAM for memory 
cache/buffers with on the host side (depending greatly on what vm.swappiness 
camp you are in).  Based on the author's result output [1] (since the VM 
parameters aren't given in the paper), as relates to a disk-intensive test they 
in effect gave 2G potential caching to Xen but ~4G to KVM.  Based at least on 
the amount of free memory on my Xen/KVM hosts I don't think this "host memor
 y cache bias" can be assumed to be a bonus trait that would normally be 
present for KVM.  (And of course a cache bias would be even more noticeable in 
the 256MB Phoronix test and in the 4x128M isolation tests [2] ...)

[1] 
http://web2.clarkson.edu/projects/virtualization/benchvm/results/performance/
[2] 
http://web2.clarkson.edu/projects/virtualization/benchvm/results/isolation/xen/memory/specweb1/SPECweb_Support.20080614-100931.html

BTW, I do realize you're pointing out that we should look at scalability and 
isolation, and here I am just giving critical feedback on a 3 year old paper 
... yes you're right those are important!  I just want to make sure the tests 
are fair ;-)

Eric
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Re: [CentOS-virt] performance differences between kvm/xen

[Grant McWilliams]

> >
> > One thing that I think probably needs to be modified for our needs is a
> Dom0
> > controller to run various tests in each DomU simultaneously then collate
> the
> > date.
> > Virtual worlds are more complex than non-virtual ones. Sometimes
> something
> > runs great in on VM but drags when multiple VMs are being used.
>
> I was also going to mention that we should look at scalability and
> performance isolation.
> Some references and previous studies here:
>
> http://todddeshane.net/research/Xen_versus_KVM_20080623.pdf
> http://clarkson.edu/~jnm/publications/isolation_ExpCS_FINALSUBMISSION.pdf
> http://clarkson.edu/~jnm/publications/freenix04-clark.pdf
>
> Also, is there anybody that has access to or would be able to get
> access to run SPECvirt?
> http://www.spec.org/virt_sc2010/
>
> Thanks,
> Todd
>
>  
>

So you've already done a lot of this then Todd? Should we just be making a
standardized test out of your work?


Grant McWilliams

Some people, when confronted with a problem, think "I know, I'll use
Windows."
Now they have two problems.
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Re: [CentOS-virt] performance differences between kvm/xen

[Todd Deshane]

On Thu, Oct 21, 2010 at 3:56 PM, Grant McWilliams
 wrote:
>
>
> On Thu, Oct 21, 2010 at 12:50 PM, Grant McWilliams
>  wrote:
>>
>>
>> On Thu, Oct 21, 2010 at 3:29 AM, Karanbir Singh 
>> wrote:
>>>
>>> On 10/21/2010 12:01 AM, Grant McWilliams wrote:
>>> > So what we're on the verge of doing here is creating a test set... I'd
>>> > love to see a shell script that ran a bunch of tests, gathered data
>>> > about the system and then created an archive that would then be
>>> > uploaded
>>> > to a website which created graphs. Dreaming maybe but it would be
>>> > consistent. So what goes in our testset?
>>>
>>> I am trying to create just that - a kickstart that will build a machine
>>> as a Xen dom0, build 4 domU's, fire up puppet inside the domU's do the
>>> testing and scp results into a central git repo. Then something similar
>>> for KVM.
>>>
>>> will get the basic framework online today.
>>>
>>> - KB
>>> __
>>
>> Do you suppose you could get it to use Phoronix Test Suite so
>> we can start to have measurable stats? We could do the same thing for any
>> VM software - even
>> the ones that don't allow publishing stats in the EULA...
>>
>> I'm also wondering if we should do the whole test suite or a subset.
>> Here is the list of tests..
>>
>
> One thing that I think probably needs to be modified for our needs is a Dom0
> controller to run various tests in each DomU simultaneously then collate the
> date.
> Virtual worlds are more complex than non-virtual ones. Sometimes something
> runs great in on VM but drags when multiple VMs are being used.

I was also going to mention that we should look at scalability and
performance isolation.
Some references and previous studies here:

http://todddeshane.net/research/Xen_versus_KVM_20080623.pdf
http://clarkson.edu/~jnm/publications/isolation_ExpCS_FINALSUBMISSION.pdf
http://clarkson.edu/~jnm/publications/freenix04-clark.pdf

Also, is there anybody that has access to or would be able to get
access to run SPECvirt?
http://www.spec.org/virt_sc2010/

Thanks,
Todd

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http://runningxen.com
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Re: [CentOS-virt] performance differences between kvm/xen

[Pasi Kärkkäinen]

On Tue, Oct 19, 2010 at 12:47:03PM +0200, Dennis Jacobfeuerborn wrote:
> On 10/19/2010 09:41 AM, Pasi Kärkkäinen wrote:
> > On Sat, Oct 16, 2010 at 09:58:15PM +0200, Dennis Jacobfeuerborn wrote:
> >> On 10/16/2010 08:11 PM, Pasi Kärkkäinen wrote:
> >>> On Thu, Oct 14, 2010 at 02:16:42PM +0100, Bart Swedrowski wrote:
>  Hi Karanbir,
> 
>  On 14 October 2010 19:59, Karanbir Singh   wrote:
> >
> > On 10/14/2010 07:48 AM, Tom Bishop wrote:
> >> I think xen is still on top in terms of performance and featuresnow
> >
> > that is indeed what it 'feels' like, but I'm quite keen on putting some
> > numbers on that.
> 
>  I have done some testing some time ago on one of the EQ machines that
>  I got from hetzner.de.  Full spec of the machine was as following:
> 
>  * Intel® Core??? i7-920
>  * 8 GB DDR3 RAM
>  * 2 x 750 GB SATA-II HDD
> 
>  It's nothing big but even though results are quite interesting.  All
>  tests were performed on CentOS 5.5 x86_64 with PostgreSQL 8.4 (from
>  CentOS repos).
> 
> >>>
> >>> Note that 64bit Xen guests should be HVM, not PV, for best performance.
> >>> Xen HVM guests obviously still need to have PV-on-HVM drivers installed.
> >>>
> >>> 32bit Xen guests can be PV.
> >>
> >> Hm, why would HVM be faster than PV for 64 bit guests?
> >>
> >
> > It's because of the x86_64 architecture, afaik.
> >
> > There was some good technical explananation about it,
> > but I can't remember the url now.
> 
> In that case I'll have to call this advice extremely bogus and you probably 
> should refrain from passing it on. The only way I can see this being true 
> is some weird corner case.
> 

It's not bogus, you can go ask on xen-devel :)

-- Pasi

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Re: [CentOS-virt] performance differences between kvm/xen

[Grant McWilliams]

On Thu, Oct 21, 2010 at 12:50 PM, Grant McWilliams <
grantmasterfl...@gmail.com> wrote:

>
>
> On Thu, Oct 21, 2010 at 3:29 AM, Karanbir Singh wrote:
>
>> On 10/21/2010 12:01 AM, Grant McWilliams wrote:
>> > So what we're on the verge of doing here is creating a test set... I'd
>> > love to see a shell script that ran a bunch of tests, gathered data
>> > about the system and then created an archive that would then be uploaded
>> > to a website which created graphs. Dreaming maybe but it would be
>> > consistent. So what goes in our testset?
>>
>> I am trying to create just that - a kickstart that will build a machine
>> as a Xen dom0, build 4 domU's, fire up puppet inside the domU's do the
>> testing and scp results into a central git repo. Then something similar
>> for KVM.
>>
>> will get the basic framework online today.
>>
>> - KB
>> __
>>
>
> Do you suppose you could get it to use Phoronix Test Suite so
> we can start to have measurable stats? We could do the same thing for any
> VM software - even
> the ones that don't allow publishing stats in the EULA...
>
> I'm also wondering if we should do the whole test suite or a subset.
> Here is the list of tests..
>
>
One thing that I think probably needs to be modified for our needs is a Dom0
controller to run various tests in each DomU simultaneously then collate the
date.
Virtual worlds are more complex than non-virtual ones. Sometimes something
runs great in on VM but drags when multiple VMs are being used.

Grant McWilliams
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Re: [CentOS-virt] performance differences between kvm/xen

[Grant McWilliams]

On Thu, Oct 21, 2010 at 3:29 AM, Karanbir Singh wrote:

> On 10/21/2010 12:01 AM, Grant McWilliams wrote:
> > So what we're on the verge of doing here is creating a test set... I'd
> > love to see a shell script that ran a bunch of tests, gathered data
> > about the system and then created an archive that would then be uploaded
> > to a website which created graphs. Dreaming maybe but it would be
> > consistent. So what goes in our testset?
>
> I am trying to create just that - a kickstart that will build a machine
> as a Xen dom0, build 4 domU's, fire up puppet inside the domU's do the
> testing and scp results into a central git repo. Then something similar
> for KVM.
>
> will get the basic framework online today.
>
> - KB
> __
>

Do you suppose you could get it to use Phoronix Test Suite so
we can start to have measurable stats? We could do the same thing for any VM
software - even
the ones that don't allow publishing stats in the EULA...

I'm also wondering if we should do the whole test suite or a subset.
Here is the list of tests..

aio-stress
apache
battery-power-usage
blogbench
bork
build-apache
build-imagemagick
build-linux-kernel
build-mplayer
build-mysql
build-php
bullet
bwfirt
byte
c-ray
cachebench
compilebench
compliance-acpi
compliance-sensors
compress-7zip
compress-gzip
compress-lzma
compress-pbzip2
crafty
dbench
dcraw
doom3
encode-ape
encode-flac
encode-mp3
encode-ogg
encode-wavpack
espeak
et
etqw-demo-iqc
etqw-demo
etqw
ffmpeg
fhourstones
fio
fs-mark
gcrypt
geekbench
gluxmark
gmpbench
gnupg
graphics-magick
gtkperf
hdparm-read
himeno
hmmer
idle-power-usage
idle
iozone
j2dbench
java-scimark2
jgfxbat
john-the-ripper
juliagpu
jxrendermark
lightsmark
mafft
mandelbulbgpu
mandelgpu
mencoder
minion
mrbayes
n-queens
nero2d
network-loopback
nexuiz-iqc
nexuiz
npb
openarena
openssl
opstone-svd
opstone-svsp
opstone-vsp
padman
pgbench
phpbench
postmark
povray
prey
pybench
pyopencl
qgears2
quake4
ramspeed
render-bench
scimark2
smallpt-gpu
smallpt
smokin-guns
specviewperf10
specviewperf9
sqlite
stream
stresscpu2
sudokut
sunflow
supertuxkart
systester
tachyon
tiobench
tremulous
trislam
tscp
ttsiod-renderer
unigine-heaven
unigine-sanctuary
unigine-tropics
unpack-linux
urbanterror
ut2004-demo
vdrift-fps-monitor
vdrift
video-cpu-usage
video-extensions
warsow
wine-cloth
wine-domino
wine-fire2
wine-hdr
wine-metaballs
wine-vf2
wine-water
x11perf
x264
xplane9-iqc
xplane9
yafray



Grant McWilliams

.
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Re: [CentOS-virt] performance differences between kvm/xen

[Karanbir Singh]

On 10/21/2010 12:01 AM, Grant McWilliams wrote:
> So what we're on the verge of doing here is creating a test set... I'd
> love to see a shell script that ran a bunch of tests, gathered data
> about the system and then created an archive that would then be uploaded
> to a website which created graphs. Dreaming maybe but it would be
> consistent. So what goes in our testset?

I am trying to create just that - a kickstart that will build a machine 
as a Xen dom0, build 4 domU's, fire up puppet inside the domU's do the 
testing and scp results into a central git repo. Then something similar 
for KVM.

will get the basic framework online today.

- KB
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Re: [CentOS-virt] performance differences between kvm/xen

[Kelvin Edmison]

On 20/10/10 7:01 PM, "Grant McWilliams"  wrote:

> 
> 
> On Wed, Oct 20, 2010 at 6:24 AM, Tom Bishop  wrote:
>> Ok so I'd like to help, since most folks have Intel Chipsets, I have a AMD
>> 4p(16 core)/32gig memory opteron server that I'm running that we can get some
>> numbers onbut it would be nice if we could run apples to apples...I have
>> iozone loaded and can run that but would be nice to run using the same
>> parametersis there any way we could list the types of test we would like
>> to run and the actual command with options listed and then we would have some
>> thing to compare at least  level the playing field...KB, any thoughts, is
>> this a good idea?
>> 
>> 
>> On Wed, Oct 20, 2010 at 6:52 AM, Karanbir Singh  wrote:
>>> On 10/20/2010 12:35 PM, Dennis Jacobfeuerborn wrote:
 Being skeptical is the best approach in the absence of
 verifiable/falsifiable data. Today or tomorrow I'll get my hands on a new
 host system and although it is supposed to go into production immediately I
 will probably find some time to do some rudimentary benchmarking in that
 regard to see if this is worth investigating further. Right now I'm
>>> 
>>> That sounds great. I've got a machine coming online in the next few days
>>> as well and will do some testing on there. Its got 2 of these :
>>> 
>>> Intel(R) Xeon(R) CPU E5310
>>> 
>>> So not the newest/greatest, but should be fairly representative.
>>> 
 planning to use fio for block device measurements but don't know any decent
 (and uncomplicated) network i/o benchmarking tools. Any ideas what tools I
 could use to quickly get some useful data on this from the machine?
>>> 
>>> iozone and openssl speed tests are always a good thing to run as a 'warm
>>> up' to your app level testing. Since pgtest has been posted here
>>> already, I'd say that is definitely one thing to include so it creates a
>>> level of common-code-testing and comparison. mysql-bench is worth
>>> hitting as well. I have a personal interest in web app delivery, so a
>>> apache-bench hosted from an external machine hitting domU's / VM's ( but
>>> more than 1 instance, and hitting more than 1 VM / domU at the same time
>>> ) would be good to have as well.
>>> 
>>> And yes, publish lots of machine details and also details on the code /
>>> platform / versions used. I will try to do the same ( but will  limit my
>>> testing to whats already available in the distro )
>>> 
>>> thanks
>>> 
>>> - KB
>>> __
> 
> 
> So what we're on the verge of doing here is creating a test set... I'd love to
> see a shell script that ran a bunch of tests, gathered data about the system
> and then created an archive that would then be uploaded to a website which
> created graphs. Dreaming maybe but it would be consistent. So what goes in our
> testset?
> 
> Just a generic list, add to or take away form it..
> 
> * phoronix test suite ?
> * 
> * iozone
> * kernbench
> * dbench
> * bonnie++
> * iperf
> * nbench
> 
> The phoronix test suite has most tests in it in addition to many many others.
> Maybe a subset of those tests with the aim of testing Virtualization would be
> good?
> 
> Grant McWilliams

+1 for the Phoronix test suite.  I was going to suggest it too.
http://phoronix-test-suite.com/

It can publish stats to a central server which the phoronix folks maintain,
and it records the details of the server on which the test was performed.
Not sure if it's smart enough to detect a VM though.   My experience with it
has been limited so far but generally positive.

This isn't my data, but I think it's a good example of how pts can be used
to compare results from different tests and scenarios.
http://global.phoronix-test-suite.com/?k=profile&u=justapost-29384-19429-181
61

Regards,
  Kelvin

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Re: [CentOS-virt] performance differences between kvm/xen

[Grant McWilliams]

On Wed, Oct 20, 2010 at 6:24 AM, Tom Bishop  wrote:

> Ok so I'd like to help, since most folks have Intel Chipsets, I have a AMD
> 4p(16 core)/32gig memory opteron server that I'm running that we can get
> some numbers onbut it would be nice if we could run apples to apples...I
> have iozone loaded and can run that but would be nice to run using the same
> parametersis there any way we could list the types of test we would like
> to run and the actual command with options listed and then we would have
> some thing to compare at least  level the playing field...KB, any thoughts,
> is this a good idea?
>
>
> On Wed, Oct 20, 2010 at 6:52 AM, Karanbir Singh wrote:
>
>> On 10/20/2010 12:35 PM, Dennis Jacobfeuerborn wrote:
>> > Being skeptical is the best approach in the absence of
>> > verifiable/falsifiable data. Today or tomorrow I'll get my hands on a
>> new
>> > host system and although it is supposed to go into production
>> immediately I
>> > will probably find some time to do some rudimentary benchmarking in that
>> > regard to see if this is worth investigating further. Right now I'm
>>
>> That sounds great. I've got a machine coming online in the next few days
>> as well and will do some testing on there. Its got 2 of these :
>>
>> Intel(R) Xeon(R) CPU E5310
>>
>> So not the newest/greatest, but should be fairly representative.
>>
>> > planning to use fio for block device measurements but don't know any
>> decent
>> > (and uncomplicated) network i/o benchmarking tools. Any ideas what tools
>> I
>> > could use to quickly get some useful data on this from the machine?
>>
>> iozone and openssl speed tests are always a good thing to run as a 'warm
>> up' to your app level testing. Since pgtest has been posted here
>> already, I'd say that is definitely one thing to include so it creates a
>> level of common-code-testing and comparison. mysql-bench is worth
>> hitting as well. I have a personal interest in web app delivery, so a
>> apache-bench hosted from an external machine hitting domU's / VM's ( but
>> more than 1 instance, and hitting more than 1 VM / domU at the same time
>> ) would be good to have as well.
>>
>> And yes, publish lots of machine details and also details on the code /
>> platform / versions used. I will try to do the same ( but will  limit my
>> testing to whats already available in the distro )
>>
>> thanks
>>
>> - KB
>> __
>>
>

So what we're on the verge of doing here is creating a test set... I'd love
to see a shell script that ran a bunch of tests, gathered data about the
system and then created an archive that would then be uploaded to a website
which created graphs. Dreaming maybe but it would be consistent. So what
goes in our testset?

Just a generic list, add to or take away form it..


   - phoronix test suite ?
   - iozone
   - kernbench
   - dbench
   - bonnie++
   - iperf
   - nbench


The phoronix test suite has most tests in it in addition to many many
others. Maybe a subset of those tests with the aim of testing Virtualization
would be good?

Grant McWilliams
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Re: [CentOS-virt] performance differences between kvm/xen

[Tom Bishop]

Ok so I'd like to help, since most folks have Intel Chipsets, I have a AMD
4p(16 core)/32gig memory opteron server that I'm running that we can get
some numbers onbut it would be nice if we could run apples to apples...I
have iozone loaded and can run that but would be nice to run using the same
parametersis there any way we could list the types of test we would like
to run and the actual command with options listed and then we would have
some thing to compare at least  level the playing field...KB, any thoughts,
is this a good idea?

On Wed, Oct 20, 2010 at 6:52 AM, Karanbir Singh wrote:

> On 10/20/2010 12:35 PM, Dennis Jacobfeuerborn wrote:
> > Being skeptical is the best approach in the absence of
> > verifiable/falsifiable data. Today or tomorrow I'll get my hands on a new
> > host system and although it is supposed to go into production immediately
> I
> > will probably find some time to do some rudimentary benchmarking in that
> > regard to see if this is worth investigating further. Right now I'm
>
> That sounds great. I've got a machine coming online in the next few days
> as well and will do some testing on there. Its got 2 of these :
>
> Intel(R) Xeon(R) CPU E5310
>
> So not the newest/greatest, but should be fairly representative.
>
> > planning to use fio for block device measurements but don't know any
> decent
> > (and uncomplicated) network i/o benchmarking tools. Any ideas what tools
> I
> > could use to quickly get some useful data on this from the machine?
>
> iozone and openssl speed tests are always a good thing to run as a 'warm
> up' to your app level testing. Since pgtest has been posted here
> already, I'd say that is definitely one thing to include so it creates a
> level of common-code-testing and comparison. mysql-bench is worth
> hitting as well. I have a personal interest in web app delivery, so a
> apache-bench hosted from an external machine hitting domU's / VM's ( but
> more than 1 instance, and hitting more than 1 VM / domU at the same time
> ) would be good to have as well.
>
> And yes, publish lots of machine details and also details on the code /
> platform / versions used. I will try to do the same ( but will  limit my
> testing to whats already available in the distro )
>
> thanks
>
> - KB
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Re: [CentOS-virt] performance differences between kvm/xen

[Karanbir Singh]

On 10/20/2010 12:52 PM, Karanbir Singh wrote:
> iozone and openssl speed tests are always a good thing to run as a 'warm

iperf is another good tool to benchmark against, just make sure you run 
dual direction, and use a second real-iron box very closeby.

- KB
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Re: [CentOS-virt] performance differences between kvm/xen

[Karanbir Singh]

On 10/20/2010 12:35 PM, Dennis Jacobfeuerborn wrote:
> Being skeptical is the best approach in the absence of
> verifiable/falsifiable data. Today or tomorrow I'll get my hands on a new
> host system and although it is supposed to go into production immediately I
> will probably find some time to do some rudimentary benchmarking in that
> regard to see if this is worth investigating further. Right now I'm

That sounds great. I've got a machine coming online in the next few days 
as well and will do some testing on there. Its got 2 of these :

Intel(R) Xeon(R) CPU E5310

So not the newest/greatest, but should be fairly representative.

> planning to use fio for block device measurements but don't know any decent
> (and uncomplicated) network i/o benchmarking tools. Any ideas what tools I
> could use to quickly get some useful data on this from the machine?

iozone and openssl speed tests are always a good thing to run as a 'warm 
up' to your app level testing. Since pgtest has been posted here 
already, I'd say that is definitely one thing to include so it creates a 
level of common-code-testing and comparison. mysql-bench is worth 
hitting as well. I have a personal interest in web app delivery, so a 
apache-bench hosted from an external machine hitting domU's / VM's ( but 
more than 1 instance, and hitting more than 1 VM / domU at the same time 
) would be good to have as well.

And yes, publish lots of machine details and also details on the code / 
platform / versions used. I will try to do the same ( but will  limit my 
testing to whats already available in the distro )

thanks

- KB
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Re: [CentOS-virt] performance differences between kvm/xen

[Dennis Jacobfeuerborn]

On 10/20/2010 08:12 AM, Grant McWilliams wrote:
>
>  > If I understand that paper correctly, HVM+VT-d outperforms PV by quite 
> a
>  > lot (if you have VT-d support on your system).
>  >
>
> Thanks for that link. Just to make my criticism of the initial claim more
> clear: I don't claim that HVM can never be faster than PV but that you 
> need
> to understand when exactly this is the case. For example I'm not sure that
> x86_64 vs. x86 really enters into this but I can definitely see VT-d 
> making
> an impact there.
>
> Regards,
>Dennis
>
>
>
> Even though this is Intel talking I'd still be very sceptical of getting
> those numbers since this is quite the opposite of what I've seen.
> Maybe the vt-d is getting good enough to actually accelerate IO operations
> but even so that would only happen on the latest hardware.
>
> I will say that Xen has a really long packet path though.

Being skeptical is the best approach in the absence of 
verifiable/falsifiable data. Today or tomorrow I'll get my hands on a new 
host system and although it is supposed to go into production immediately I 
will probably find some time to do some rudimentary benchmarking in that 
regard to see if this is worth investigating further. Right now I'm 
planning to use fio for block device measurements but don't know any decent 
(and uncomplicated) network i/o benchmarking tools. Any ideas what tools I 
could use to quickly get some useful data on this from the machine?

Regards,
   Dennis
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Re: [CentOS-virt] performance differences between kvm/xen

[Grant McWilliams]

> > If I understand that paper correctly, HVM+VT-d outperforms PV by quite a
> > lot (if you have VT-d support on your system).
> >
>
> Thanks for that link. Just to make my criticism of the initial claim more
> clear: I don't claim that HVM can never be faster than PV but that you need
> to understand when exactly this is the case. For example I'm not sure that
> x86_64 vs. x86 really enters into this but I can definitely see VT-d making
> an impact there.
>
> Regards,
>Dennis
>
>
>
Even though this is Intel talking I'd still be very sceptical of getting
those numbers since this is quite the opposite of what I've seen.
Maybe the vt-d is getting good enough to actually accelerate IO operations
but even so that would only happen on the latest hardware.

I will say that Xen has a really long packet path though.

Grant McWilliams
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Re: [CentOS-virt] performance differences between kvm/xen

[Dennis Jacobfeuerborn]

On 10/19/2010 01:16 PM, Jerry Franz wrote:
>On 10/19/2010 03:47 AM, Dennis Jacobfeuerborn wrote:
>> On 10/19/2010 09:41 AM, Pasi Kärkkäinen wrote:
>>>
>>> It's because of the x86_64 architecture, afaik.
>>>
>>> There was some good technical explananation about it,
>>> but I can't remember the url now.
>> In that case I'll have to call this advice extremely bogus and you probably
>> should refrain from passing it on. The only way I can see this being true
>> is some weird corner case.
> There appear to be some interactions with the Intel VT-d processor features.
>
> http://www.xen.org/files/xensummit_intel09/xensummit2009_IOVirtPerf.pdf
>
> If I understand that paper correctly, HVM+VT-d outperforms PV by quite a
> lot (if you have VT-d support on your system).
>

Thanks for that link. Just to make my criticism of the initial claim more 
clear: I don't claim that HVM can never be faster than PV but that you need 
to understand when exactly this is the case. For example I'm not sure that 
x86_64 vs. x86 really enters into this but I can definitely see VT-d making 
an impact there.

Regards,
   Dennis

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Re: [CentOS-virt] performance differences between kvm/xen

[Lucas Timm LH]

Hi guys,

Sorry by late reading this thread. I had already compared Xen Source with
KVM (and btw, VMware Server 2) in CentOS 5.2 days (2008) for a college job.
At this time Xen have more performance than the others, but I'd tested in my
desktop: A Core 2 Duo E6420 with 3GB Ram. All the papers I'd used is
available in brazilian portuguese, if anyone is interesed I would send. But
*IMHO* isn't interesting translating the job to english because, as I said,
I did it in CentOS 5.2 (2008) and a *LOT* things has changed in all this
hypervisors.

Anyway, here in my job I have two IBMs x3400 (two Xeon 5504 sockets with 8GB
Ram and 2 x 160GB [SAS? SATA? I really don't know]) available, and they
works perfect with Xen and KVM (both worked as Dom0 before, so we replaced
them for rack mounted machines). I really like x86 virtualization, so I can
test the hypervisors again in this real servers and write about it in my
free time, but I need a metodology to follow up and do a benchmark. (I'm not
good in performance metter). If someone else is interesed in do it with me,
will be really fun.



2010/10/19 Jerry Franz 

>   On 10/19/2010 03:47 AM, Dennis Jacobfeuerborn wrote:
> > On 10/19/2010 09:41 AM, Pasi Kärkkäinen wrote:
> >>
> >> It's because of the x86_64 architecture, afaik.
> >>
> >> There was some good technical explananation about it,
> >> but I can't remember the url now.
> > In that case I'll have to call this advice extremely bogus and you
> probably
> > should refrain from passing it on. The only way I can see this being true
> > is some weird corner case.
> There appear to be some interactions with the Intel VT-d processor
> features.
>
> http://www.xen.org/files/xensummit_intel09/xensummit2009_IOVirtPerf.pdf
>
> If I understand that paper correctly, HVM+VT-d outperforms PV by quite a
> lot (if you have VT-d support on your system).
>
> --
> Benjamin Franz
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-- 
Lucas Timm, Goiânia/GO.
http://timmerman.wordpress.com

(62) 8198-0867
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Re: [CentOS-virt] performance differences between kvm/xen

[Jerry Franz]

  On 10/19/2010 03:47 AM, Dennis Jacobfeuerborn wrote:
> On 10/19/2010 09:41 AM, Pasi Kärkkäinen wrote:
>>
>> It's because of the x86_64 architecture, afaik.
>>
>> There was some good technical explananation about it,
>> but I can't remember the url now.
> In that case I'll have to call this advice extremely bogus and you probably
> should refrain from passing it on. The only way I can see this being true
> is some weird corner case.
There appear to be some interactions with the Intel VT-d processor features.

http://www.xen.org/files/xensummit_intel09/xensummit2009_IOVirtPerf.pdf

If I understand that paper correctly, HVM+VT-d outperforms PV by quite a 
lot (if you have VT-d support on your system).

-- 
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Re: [CentOS-virt] performance differences between kvm/xen

[Dennis Jacobfeuerborn]

On 10/19/2010 09:41 AM, Pasi Kärkkäinen wrote:
> On Sat, Oct 16, 2010 at 09:58:15PM +0200, Dennis Jacobfeuerborn wrote:
>> On 10/16/2010 08:11 PM, Pasi Kärkkäinen wrote:
>>> On Thu, Oct 14, 2010 at 02:16:42PM +0100, Bart Swedrowski wrote:
 Hi Karanbir,

 On 14 October 2010 19:59, Karanbir Singh   wrote:
>
> On 10/14/2010 07:48 AM, Tom Bishop wrote:
>> I think xen is still on top in terms of performance and featuresnow
>
> that is indeed what it 'feels' like, but I'm quite keen on putting some
> numbers on that.

 I have done some testing some time ago on one of the EQ machines that
 I got from hetzner.de.  Full spec of the machine was as following:

 * Intel® Core??? i7-920
 * 8 GB DDR3 RAM
 * 2 x 750 GB SATA-II HDD

 It's nothing big but even though results are quite interesting.  All
 tests were performed on CentOS 5.5 x86_64 with PostgreSQL 8.4 (from
 CentOS repos).

>>>
>>> Note that 64bit Xen guests should be HVM, not PV, for best performance.
>>> Xen HVM guests obviously still need to have PV-on-HVM drivers installed.
>>>
>>> 32bit Xen guests can be PV.
>>
>> Hm, why would HVM be faster than PV for 64 bit guests?
>>
>
> It's because of the x86_64 architecture, afaik.
>
> There was some good technical explananation about it,
> but I can't remember the url now.

In that case I'll have to call this advice extremely bogus and you probably 
should refrain from passing it on. The only way I can see this being true 
is some weird corner case.

Regards,
   Dennis
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Re: [CentOS-virt] performance differences between kvm/xen

[Pasi Kärkkäinen]

On Sat, Oct 16, 2010 at 09:58:15PM +0200, Dennis Jacobfeuerborn wrote:
> On 10/16/2010 08:11 PM, Pasi Kärkkäinen wrote:
> > On Thu, Oct 14, 2010 at 02:16:42PM +0100, Bart Swedrowski wrote:
> >> Hi Karanbir,
> >>
> >> On 14 October 2010 19:59, Karanbir Singh  wrote:
> >>>
> >>> On 10/14/2010 07:48 AM, Tom Bishop wrote:
>  I think xen is still on top in terms of performance and featuresnow
> >>>
> >>> that is indeed what it 'feels' like, but I'm quite keen on putting some
> >>> numbers on that.
> >>
> >> I have done some testing some time ago on one of the EQ machines that
> >> I got from hetzner.de.  Full spec of the machine was as following:
> >>
> >>* Intel® Core??? i7-920
> >>* 8 GB DDR3 RAM
> >>* 2 x 750 GB SATA-II HDD
> >>
> >> It's nothing big but even though results are quite interesting.  All
> >> tests were performed on CentOS 5.5 x86_64 with PostgreSQL 8.4 (from
> >> CentOS repos).
> >>
> >
> > Note that 64bit Xen guests should be HVM, not PV, for best performance.
> > Xen HVM guests obviously still need to have PV-on-HVM drivers installed.
> >
> > 32bit Xen guests can be PV.
> 
> Hm, why would HVM be faster than PV for 64 bit guests?
> 

It's because of the x86_64 architecture, afaik.

There was some good technical explananation about it,
but I can't remember the url now.

-- Pasi

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Re: [CentOS-virt] performance differences between kvm/xen

[Grant McWilliams]

On Sat, Oct 16, 2010 at 12:58 PM, Dennis Jacobfeuerborn <
denni...@conversis.de> wrote:

> On 10/16/2010 08:11 PM, Pasi Kärkkäinen wrote:
> > On Thu, Oct 14, 2010 at 02:16:42PM +0100, Bart Swedrowski wrote:
> >> Hi Karanbir,
> >>
> >> On 14 October 2010 19:59, Karanbir Singh  wrote:
> >>>
> >>> On 10/14/2010 07:48 AM, Tom Bishop wrote:
>  I think xen is still on top in terms of performance and
> featuresnow
> >>>
> >>> that is indeed what it 'feels' like, but I'm quite keen on putting some
> >>> numbers on that.
> >>
> >> I have done some testing some time ago on one of the EQ machines that
> >> I got from hetzner.de.  Full spec of the machine was as following:
> >
> > Note that 64bit Xen guests should be HVM, not PV, for best performance.
> > Xen HVM guests obviously still need to have PV-on-HVM drivers installed.
> >
> > 32bit Xen guests can be PV.
>
> Hm, why would HVM be faster than PV for 64 bit guests?
>
> Regards,
>Dennis
>

lol, there's seems to be a lot of hearsay surrounding performance and Xen.



Grant McWilliams

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Windows."
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Re: [CentOS-virt] performance differences between kvm/xen

[Dennis Jacobfeuerborn]

On 10/16/2010 08:11 PM, Pasi Kärkkäinen wrote:
> On Thu, Oct 14, 2010 at 02:16:42PM +0100, Bart Swedrowski wrote:
>> Hi Karanbir,
>>
>> On 14 October 2010 19:59, Karanbir Singh  wrote:
>>>
>>> On 10/14/2010 07:48 AM, Tom Bishop wrote:
 I think xen is still on top in terms of performance and featuresnow
>>>
>>> that is indeed what it 'feels' like, but I'm quite keen on putting some
>>> numbers on that.
>>
>> I have done some testing some time ago on one of the EQ machines that
>> I got from hetzner.de.  Full spec of the machine was as following:
>>
>>* Intel® Core??? i7-920
>>* 8 GB DDR3 RAM
>>* 2 x 750 GB SATA-II HDD
>>
>> It's nothing big but even though results are quite interesting.  All
>> tests were performed on CentOS 5.5 x86_64 with PostgreSQL 8.4 (from
>> CentOS repos).
>>
>
> Note that 64bit Xen guests should be HVM, not PV, for best performance.
> Xen HVM guests obviously still need to have PV-on-HVM drivers installed.
>
> 32bit Xen guests can be PV.

Hm, why would HVM be faster than PV for 64 bit guests?

Regards,
   Dennis
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Re: [CentOS-virt] performance differences between kvm/xen

[Pasi Kärkkäinen]

On Thu, Oct 14, 2010 at 02:16:42PM +0100, Bart Swedrowski wrote:
> Hi Karanbir,
> 
> On 14 October 2010 19:59, Karanbir Singh  wrote:
> >
> > On 10/14/2010 07:48 AM, Tom Bishop wrote:
> > > I think xen is still on top in terms of performance and featuresnow
> >
> > that is indeed what it 'feels' like, but I'm quite keen on putting some
> > numbers on that.
> 
> I have done some testing some time ago on one of the EQ machines that
> I got from hetzner.de.  Full spec of the machine was as following:
> 
>   * Intel® Core??? i7-920
>   * 8 GB DDR3 RAM
>   * 2 x 750 GB SATA-II HDD
> 
> It's nothing big but even though results are quite interesting.  All
> tests were performed on CentOS 5.5 x86_64 with PostgreSQL 8.4 (from
> CentOS repos).
> 

Note that 64bit Xen guests should be HVM, not PV, for best performance.
Xen HVM guests obviously still need to have PV-on-HVM drivers installed.

32bit Xen guests can be PV.

-- Pasi

> I have run some PostgreSQL PGBench tests as well as Bonnie++ tests.
> The PostgreSQL tests was divided into two tests having three goes (to
> get an idea of average).  The commands I used for testing were:
> 
> > dropdb pgbench && sync && sleep 3 && createdb pgbench && sync && sleep 3
> > pgbench -i -s 100 -U postgres -d pgbench && sync && sleep 3
> > pgbench -c 10 -t 5000 -s 100 -U postgres -d pgbench 2>/dev/null && sync \
> > && sleep 3 && pgbench -c 10 -t 5000 -s 100 -U postgres -d pgbench 
> > 2>/dev/null \
> > && sync && sleep 3 && pgbench -c 10 -t 5000 -s 100 -U postgres -d pgbench 
> > 2>/dev/null \
> > && sync && sleep 3
> 
> Now results.  First CentOS5/x86_64 without any virtualisation, without
> any PostgreSQL optimisation:
> 
> -bash-3.2$ pgbench -c 10 -t 5000 -s 100 -U postgres -d pgbench 2>/dev/null
> pghost:  pgport:  nclients: 10 nxacts: 5000 dbName: pgbench
> transaction type: TPC-B (sort of)
> scaling factor: 100
> number of clients: 10
> number of transactions per client: 5000
> number of transactions actually processed: 5/5
> tps = 141.191292 (including connections establishing)
> tps = 141.196776 (excluding connections establishing)
> -bash-3.2$ pgbench -c 10 -t 5000 -s 100 -U postgres -d pgbench 2>/dev/null
> pghost:  pgport:  nclients: 10 nxacts: 5000 dbName: pgbench
> transaction type: TPC-B (sort of)
> scaling factor: 100
> number of clients: 10
> number of transactions per client: 5000
> number of transactions actually processed: 5/5
> tps = 156.479561 (including connections establishing)
> tps = 156.486222 (excluding connections establishing)
> -bash-3.2$ pgbench -c 10 -t 5000 -s 100 -U postgres -d pgbench 2>/dev/null
> pghost:  pgport:  nclients: 10 nxacts: 5000 dbName: pgbench
> transaction type: TPC-B (sort of)
> scaling factor: 100
> number of clients: 10
> number of transactions per client: 5000
> number of transactions actually processed: 5/5
> tps = 164.880109 (including connections establishing)
> tps = 164.888009 (excluding connections establishing)
> 
> Now after optimisation (shared_buffers, effective_cache_size etc.):
> 
> pghost:  pgport:  nclients: 10 nxacts: 5000 dbName: pgbench
> transaction type: TPC-B (sort of)
> scaling factor: 100
> number of clients: 10
> number of transactions per client: 5000
> number of transactions actually processed: 5/5
> tps = 403.430951 (including connections establishing)
> tps = 403.474562 (excluding connections establishing)
> pghost:  pgport:  nclients: 10 nxacts: 5000 dbName: pgbench
> transaction type: TPC-B (sort of)
> scaling factor: 100
> number of clients: 10
> number of transactions per client: 5000
> number of transactions actually processed: 5/5
> tps = 336.060764 (including connections establishing)
> tps = 336.093214 (excluding connections establishing)
> pghost:  pgport:  nclients: 10 nxacts: 5000 dbName: pgbench
> transaction type: TPC-B (sort of)
> scaling factor: 100
> number of clients: 10
> number of transactions per client: 5000
> number of transactions actually processed: 5/5
> tps = 446.607705 (including connections establishing)
> tps = 446.664466 (excluding connections establishing)
> 
> Now KVM based VM with 7GB RAM and 8 CPUs.  Using virtio and LVM
> partitions as backend.
> 
> PostgreSQL results *w/o* optimisation.
> 
> -bash-3.2$ pgbench -c 10 -t 5000 -s 100 -U postgres -d pgbench
> 2>/dev/null && sync && sleep 3 && pgbench -c 10 -t 5000 -s 100 -U
> postgres -d pgbench 2>/dev/null && sync && sleep 3 && pgbench -c 10 -t
> 5000 -s 100 -U postgres -d pgbench 2>/dev/null && sync && sleep 3
> pghost:  pgport:  nclients: 10 nxacts: 5000 dbName: pgbench
> transaction type: TPC-B (sort of)
> scaling factor: 100
> number of clients: 10
> number of transactions per client: 5000
> number of transactions actually processed: 5/5
> tps = 124.578488 (including connections establishing)
> tps = 124.585776 (excluding connections establishing)
> pghost:  pgport:  nclients: 10 nxacts: 5000 dbName: pgbench
> transaction type: TPC-B (sort of)
> scaling

Re: [CentOS-virt] performance differences between kvm/xen

[Karanbir Singh]

On 10/15/2010 10:56 PM, compdoc wrote:
> I think he's right. Run PostgreSQL on the centos host directly, rather than
> from within a guest. The vm guests could access the database over the
> virtual lan, so speed of access for guests on the same server wouldn't be an
> issue.

I don't understand why that would have an issue with Xen, quite a lot of 
hosting companies run mysql on the dom0's and let all the VM's hosted on 
the box access it over a socket.

- KB
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Re: [CentOS-virt] performance differences between kvm/xen

[compdoc]

I think he's right. Run PostgreSQL on the centos host directly, rather than
from within a guest. The vm guests could access the database over the
virtual lan, so speed of access for guests on the same server wouldn't be an
issue.

There are lots of ways of file sharing for example. You can share from
within a linux or windows guest, or you could share directly from the centos
host with samba or iSCSI.

I get native speeds from guests, but I think running directly from the
server is always going to be faster.




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Re: [CentOS-virt] performance differences between kvm/xen

[Karanbir Singh]

On 10/15/2010 02:00 PM, John L. Magee wrote:
> One thing to possibly consider with PostgreSQL performance especially,
> is that when using KVM VMs for some applications, PostgreSQL could be
> run native. This is a viable approach with KVM that could never work
> with Xen.

Can you expand on this a little bit please ?

- KB
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Re: [CentOS-virt] performance differences between kvm/xen

[John L. Magee]

One thing to possibly consider with PostgreSQL performance especially,
is that when using KVM VMs for some applications, PostgreSQL could be
run native. This is a viable approach with KVM that could never work
with Xen.

 

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Re: [CentOS-virt] performance differences between kvm/xen

[Bart Swedrowski]

Hi Karanbir,

On 14 October 2010 19:59, Karanbir Singh  wrote:
>
> On 10/14/2010 07:48 AM, Tom Bishop wrote:
> > I think xen is still on top in terms of performance and featuresnow
>
> that is indeed what it 'feels' like, but I'm quite keen on putting some
> numbers on that.

I have done some testing some time ago on one of the EQ machines that
I got from hetzner.de.  Full spec of the machine was as following:

  * Intel® Core™ i7-920
  * 8 GB DDR3 RAM
  * 2 x 750 GB SATA-II HDD

It's nothing big but even though results are quite interesting.  All
tests were performed on CentOS 5.5 x86_64 with PostgreSQL 8.4 (from
CentOS repos).

I have run some PostgreSQL PGBench tests as well as Bonnie++ tests.
The PostgreSQL tests was divided into two tests having three goes (to
get an idea of average).  The commands I used for testing were:

> dropdb pgbench && sync && sleep 3 && createdb pgbench && sync && sleep 3
> pgbench -i -s 100 -U postgres -d pgbench && sync && sleep 3
> pgbench -c 10 -t 5000 -s 100 -U postgres -d pgbench 2>/dev/null && sync \
> && sleep 3 && pgbench -c 10 -t 5000 -s 100 -U postgres -d pgbench 2>/dev/null 
> \
> && sync && sleep 3 && pgbench -c 10 -t 5000 -s 100 -U postgres -d pgbench 
> 2>/dev/null \
> && sync && sleep 3

Now results.  First CentOS5/x86_64 without any virtualisation, without
any PostgreSQL optimisation:

-bash-3.2$ pgbench -c 10 -t 5000 -s 100 -U postgres -d pgbench 2>/dev/null
pghost:  pgport:  nclients: 10 nxacts: 5000 dbName: pgbench
transaction type: TPC-B (sort of)
scaling factor: 100
number of clients: 10
number of transactions per client: 5000
number of transactions actually processed: 5/5
tps = 141.191292 (including connections establishing)
tps = 141.196776 (excluding connections establishing)
-bash-3.2$ pgbench -c 10 -t 5000 -s 100 -U postgres -d pgbench 2>/dev/null
pghost:  pgport:  nclients: 10 nxacts: 5000 dbName: pgbench
transaction type: TPC-B (sort of)
scaling factor: 100
number of clients: 10
number of transactions per client: 5000
number of transactions actually processed: 5/5
tps = 156.479561 (including connections establishing)
tps = 156.486222 (excluding connections establishing)
-bash-3.2$ pgbench -c 10 -t 5000 -s 100 -U postgres -d pgbench 2>/dev/null
pghost:  pgport:  nclients: 10 nxacts: 5000 dbName: pgbench
transaction type: TPC-B (sort of)
scaling factor: 100
number of clients: 10
number of transactions per client: 5000
number of transactions actually processed: 5/5
tps = 164.880109 (including connections establishing)
tps = 164.888009 (excluding connections establishing)

Now after optimisation (shared_buffers, effective_cache_size etc.):

pghost:  pgport:  nclients: 10 nxacts: 5000 dbName: pgbench
transaction type: TPC-B (sort of)
scaling factor: 100
number of clients: 10
number of transactions per client: 5000
number of transactions actually processed: 5/5
tps = 403.430951 (including connections establishing)
tps = 403.474562 (excluding connections establishing)
pghost:  pgport:  nclients: 10 nxacts: 5000 dbName: pgbench
transaction type: TPC-B (sort of)
scaling factor: 100
number of clients: 10
number of transactions per client: 5000
number of transactions actually processed: 5/5
tps = 336.060764 (including connections establishing)
tps = 336.093214 (excluding connections establishing)
pghost:  pgport:  nclients: 10 nxacts: 5000 dbName: pgbench
transaction type: TPC-B (sort of)
scaling factor: 100
number of clients: 10
number of transactions per client: 5000
number of transactions actually processed: 5/5
tps = 446.607705 (including connections establishing)
tps = 446.664466 (excluding connections establishing)

Now KVM based VM with 7GB RAM and 8 CPUs.  Using virtio and LVM
partitions as backend.

PostgreSQL results *w/o* optimisation.

-bash-3.2$ pgbench -c 10 -t 5000 -s 100 -U postgres -d pgbench
2>/dev/null && sync && sleep 3 && pgbench -c 10 -t 5000 -s 100 -U
postgres -d pgbench 2>/dev/null && sync && sleep 3 && pgbench -c 10 -t
5000 -s 100 -U postgres -d pgbench 2>/dev/null && sync && sleep 3
pghost:  pgport:  nclients: 10 nxacts: 5000 dbName: pgbench
transaction type: TPC-B (sort of)
scaling factor: 100
number of clients: 10
number of transactions per client: 5000
number of transactions actually processed: 5/5
tps = 124.578488 (including connections establishing)
tps = 124.585776 (excluding connections establishing)
pghost:  pgport:  nclients: 10 nxacts: 5000 dbName: pgbench
transaction type: TPC-B (sort of)
scaling factor: 100
number of clients: 10
number of transactions per client: 5000
number of transactions actually processed: 5/5
tps = 140.451736 (including connections establishing)
tps = 140.463105 (excluding connections establishing)
pghost:  pgport:  nclients: 10 nxacts: 5000 dbName: pgbench
transaction type: TPC-B (sort of)
scaling factor: 100
number of clients: 10
number of transactions per client: 5000
number of transactions actually processed: 5/5
tps = 1

Re: [CentOS-virt] performance differences between kvm/xen

[Tom Bishop]

When you get the numbers please share, as I for one would be very
interestedI have read some on the web but nothing as of late.I just
don't have the time right now to go benchmark anything

On Thu, Oct 14, 2010 at 1:59 PM, Karanbir Singh wrote:

> On 10/14/2010 07:48 AM, Tom Bishop wrote:
> > I think xen is still on top in terms of performance and featuresnow
>
> that is indeed what it 'feels' like, but I'm quite keen on putting some
> numbers on that.
>
> > having said that my experience in the past with kvm and my latest
> > testing with 5.5 and KVM I can say that KVM has made great strides with
> > the virtio drivers for the disk and nic, my latest vm's that I am using
> > with those drivers are very snappy and so far I am very pleased.I'm
>
> I will try and get a machine up with centos dom0 and do some metrics.
>
> - KB
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Re: [CentOS-virt] performance differences between kvm/xen

[Edgar Rodolfo]

2010/10/14 Karanbir Singh 

> On 10/14/2010 07:48 AM, Tom Bishop wrote:
> > I think xen is still on top in terms of performance and featuresnow
>
> that is indeed what it 'feels' like, but I'm quite keen on putting some
> numbers on that.
>
> > having said that my experience in the past with kvm and my latest
> > testing with 5.5 and KVM I can say that KVM has made great strides with
> > the virtio drivers for the disk and nic, my latest vm's that I am using
> > with those drivers are very snappy and so far I am very pleased.I'm
>
> I will try and get a machine up with centos dom0 and do some metrics.
>
> - KB
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Not all the microprocessor support virtualization with kvm
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Re: [CentOS-virt] performance differences between kvm/xen

[Karanbir Singh]

On 10/14/2010 07:48 AM, Tom Bishop wrote:
> I think xen is still on top in terms of performance and featuresnow

that is indeed what it 'feels' like, but I'm quite keen on putting some 
numbers on that.

> having said that my experience in the past with kvm and my latest
> testing with 5.5 and KVM I can say that KVM has made great strides with
> the virtio drivers for the disk and nic, my latest vm's that I am using
> with those drivers are very snappy and so far I am very pleased.I'm

I will try and get a machine up with centos dom0 and do some metrics.

- KB
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Re: [CentOS-virt] performance differences between kvm/xen

[Tom Bishop]

I don't have any benchmarks per se just my recent testing of them

I think xen is still on top in terms of performance and featuresnow
having said that my experience in the past with kvm and my latest testing
with 5.5 and KVM I can say that KVM has made great strides with the virtio
drivers for the disk and nic, my latest vm's that I am using with those
drivers are very snappy and so far I am very pleased.I'm a big redhat
fan and think that KVM will only continue to get better and I believe at
some point will equal or pass xenI'm waiting for rhel6 to see what they
are going to be rolling out...I have not had any time to play with the beta
or look at fedora

On Thu, Oct 14, 2010 at 11:32 AM, Karanbir Singh wrote:

> hi guys,
>
> Just wondering if anyone has done any performance testing between kvm
> and xen on CentOS-5 ( using centos as host and vm in every case ) ?
>
> Regards,
>
> --
> Karanbir Singh
> London, UK   | http://www.karan.org/ | twitter.com/kbsingh
> ICQ: 2522219 | Yahoo IM: z00dax  | Gtalk: z00dax
> GnuPG Key : http://www.karan.org/publickey.asc
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[CentOS-virt] performance differences between kvm/xen

[Karanbir Singh]

hi guys,

Just wondering if anyone has done any performance testing between kvm 
and xen on CentOS-5 ( using centos as host and vm in every case ) ?

Regards,

-- 
Karanbir Singh
London, UK   | http://www.karan.org/ | twitter.com/kbsingh
ICQ: 2522219 | Yahoo IM: z00dax  | Gtalk: z00dax
GnuPG Key : http://www.karan.org/publickey.asc
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