KVM benchmarks (compared to vmware)

[Martin Vogt <vogt@itwm.fraunhofer.de>]

Hello list,

I did some benchmarks over the weekend and compared
kvm-78 on a 2.6.27.4-2-default against vmware server 2.0.0-122956

Host Machine:
- Host E8400 (3GHz) 2GB RAM
- virtual machines are on iSCSI or NFS
- virtual machine is booted with -m 1024 and e1000

1. Bench
=========

Installation of SuSE 11.1: (time to finish)
1. iSCSI kvm : 48 min
2. NFS   kvm : 54 min (qcow image)
3. VMWare    : 38 min

2. Bench
========
Booting of SuSE 11.1 beta4 (from grub to getty prompt)
(with coldcache, http://linux-mm.org/Drop_Caches)

1. iSCSI kvm : 33 sec
2. NFS   kvm : 44 sec
3. VMWare    : 34 sec

same, with "hotcache".

1. iSCSI kvm : 22 sec
2. NFS   kvm : 23 sec
3. VMWare    : 21 sec

3. Bench
=========
Now the NIC performance from within the VM to the outer world,
(measured with tcpspray--program writes to the discard service over tcp)

VM->outer world

1. iSCSI kvm : 12 MB/s
2. NFS   kvm : 12 MB/s
3. VMWare    : 50 MB/s

now the reverse:

outer world->VM

1. iSCSI kvm : 50 MB/s
2. NFS   kvm : 50 MB/s
3. VMWare    : 100 MB/s

but here the kvm results varies from 30MB/s - 70MB/s


4. Bench
========

Now iozone benchmarks, which measure the "virtual drive" of the
VM: IOZone write a 2GB file to /tmp , writes it again reads it and reads
it again. (Two runs with 2GB and 4GB file size)

1. iSCSI-kvm:
KB	write	re-writeread	re-read
2097152	24131	25349	44325	46055
4194304	25056	25419	44917	44654
avg:	24593	25382	44621	45354


2. NFS-kvm:
KB	write	re-writeread	re-read
2097152	7584	37846	43334	42654
4194304	12185	20558	37075	40029
avg     9884	29202	40204	41341

2a (because of qcow effect) second run:
KB	write	re-writeread	re-read
2097152	35980	33474	42010	43395
4194304	21675	20732	37976	39134
avg     28827	27103	39993	41264


3 VMWARE:
KB	write	re-writeread	re-read
2097152	56168	47829	12568	11688
4194304	47315	32088	10897	10801
avg     51741	39958	11732	11244



RESULT
=======


As a result I would say, that the virtual NIC in VMware is much faster
(if you see tcpspray as benchmark)
And the write performace of VMWare is better 50MB/s againt 29MB/s in
kvm. But VMWare seems to have a horrible read performance (11MB/s vs.
44MB/s)

But in general VMWare is faster, at least during the installation
benchmarks (38min vs 48 min with kvm)
Maybe these benches could give an idea for future improvements, but
I wont say that kvm is slow, its fast enough, but maybe has room for
improvements.  :-)

regards,

Martin