[OmniOS-discuss] Potential KVM Virtio Performance Issues

John Barfield john.barfield at bissinc.com
Tue Mar 24 19:29:45 UTC 2015

Greetings OmnisOS community! This is my first time to ask a question on 
this list so here goes. I’ve deployed a zone on omnios and a KVM virtual 
machine within the zone. I’ve been doing some initial virtio network 
interface performance testing with iperf and the following are my results 
(default out of the box for all moving parts). 

OmniOS build stable: r151012
Test Interfaces:
GZ Phys = igb0
KVM Vnic: kvm0 over igb0
GZ Vnic: gvm0 over igb0
Zone Vnic: zvm0 over igb0

Network addressing: All vnics are with

Zone Brand: Omni-ti ipkg
Qemu-Kvm Guest: Centos 6.6 x86_64

iPerf Results:

KVM Guest -> Global Zone = 151 Mbytes (Expected close to 1 GByte)

KVM Guest -> KVM Zone = 147 Mbytes (Expected close to 1 GByte)

Zone -> Global Zone = 5.0GBytes (These were expected since it was a host 
only VNIC network)

GZ -> Zone = 4.7 Gbytes (These were expected since it was a host only VNIC 

My question is are there any tweaks that I’m missing to get the full 
performance potential within the guest? Why am I only seeing 147 Mbytes 
between KVM and the hosting zone or the global zone? 

I’m testing with an isolated network and vnics only, so the traffic is 
never leaving the physical host to go over the wire.

I do have cpu capped at 16 cores and memory capped at 16GB of memory in 
the zone. Is there some default network capping that I’m missing? Or 
process throttling?

MTU is 1500 across the board. 

I did the same test with etherstubs at first but though maybe I was having 
an MTU mismatch because I received the same 147 Mbyte result…however a 
subsequent test using just the GZ -> child zone showed 5.0GBps over the 
etherstub switch just like when I only used the VNIC’s over igb0.  

Also just for grins I tested two bare metal hosts on my physical network 
with iperf…one being CentOS 6.5 and the other OmniOS build r151012 and 
received 1.09 Gbytes over a physical switch. 

Your thoughts are appreciated!

John Barfield / Sr Principal Engineer
+1 (214) 425-0783/ john.barfield at bissinc.com
BISS, Inc. Office: +1 (214) 506-8354 

4925 Greenville Ave Suite 900
Dallas, TX 75206
support.bissinc.com <http://htmlsig.com/support.bissinc.com>

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