[OmniOS-discuss] kvm performance regresseion r10 -> r12

[Dan McDonald]

> On Oct 29, 2014, at 9:31 AM, Tobias Oetiker <tobi at oetiker.ch> wrote:
> 
> I am still running omnios r10 ...being reluctant to upgrade,
> because we find that kvm virtio network performance seems to have
> taken a severe hit from r10 to r12
> 
> I am runing this simple test:
> 
>  hw-box$ ssh -c aes256-ctr kvm-guest dd if=/dev/zero bs=10M count=10 > /dev/null
> 
> On r10 I get 31 MB/s
> 
> On r12 I get 21 MB/s
> 
> 
> On both systems we are running kvm with the magic
> 
>  -device-virtio-net-pci,mac=$mac,tx=timer,x-txtimer=200000,x-txburst=128,vlan=0
>  -net vnic,vlan=0,name=net0,ifname=$VNIC,macaddr=$mac
> 
> 
> Questions
> 
> a) do you see that too ?
> 
> b) any ideas what could be causing it ?

I'll be honest --> there are no changes in the virtio code between r151010 and r151012:

r151012(~/ws/illumos-omnios)[0]% git branch
* r151012
r151012(~/ws/illumos-omnios)[0]% git whatchanged origin/r151010.. | grep vir
    5004 load average should be virtualized for zones
:100644 100644 558abd8... 2e82787... M  usr/src/man/man5/environ.5
r151012(~/ws/illumos-omnios)[0]% 

Also, if you're measuring network performance only, use netperf or at least iperf (both are packages you'll have to download and compile for now), as they are better equipped to tell you (esp. netperf) if you're seeing problems in latency, bandwidth, or both.

Dan