[OmniOS-discuss] kvm io 10 times slower after r151010 -> r151012 upgrade

[Tobias Oetiker]

Hi Michael,

Today Michael Mounteney wrote:

> On Wed, 10 Dec 2014 06:14:56 +0100 (CET)
> Tobias Oetiker <tobi at oetiker.ch> wrote:
>
> > This leads me to suspect, that either only very few people are
> > using omnios as a kvm server OR it is also a hardware dependent
> > problem.
>
> I think it must be.  I'm running KVM (Gentoo Linux guests) and have
> just gone from 151010 to 151012.  I haven't carried-out any
> quantitative assessment, but didn't notice any slowdown.  For the
> record, my KVM invocation is:
>
> /usr/bin/qemu-system-x86_64 \
>         -name "Gentoo "$WHAT \
>         -cpu host \
>         -boot order=d \
>         -enable-kvm \
>         -vnc cortex:$VNC \
>         -smp 1,maxcpus=1,cores=2 \
>         -m 1024 \
>         -no-hpet \
>         -localtime \
>         -kernel /gentoo/kernel-source/linux-3.17.4-gentoo-vbox/arch/x86/boot/bzImage \
>         -append "root=/dev/vda1 init=/usr/lib/systemd/systemd quiet" \
>         -drive file=/dev/zvol/dsk/rpool/vol/Gentoo-KVM-${WHAT},cache=none,if=virtio,index=0 \
>         -drive file=/dev/zvol/dsk/rpool/vol/Linuswap-${WHAT},cache=none,if=virtio,index=1 \
>         -net nic,vlan=0,macaddr=$mac,model=virtio,name=ncard1 \
>         -net vnic,vlan=0,name=net0,ifname=$VNIC,macaddr=$mac \
>         -monitor telnet:127.0.0.1:${monitor},server,nowait \
>         -vga std \
>         -daemonize
>
> where ${WHAT} is either KDE or XFCE.  Machine is a Supermicro 5017C-LF with 1 x Intel Xeon E3-1240V2 3.40 GHz.4 Cores , 4 Threads,8Mb cache and 8 GiB RAM.
>
> If you are interested in any performance figures, let me know any tar or dd etc. commands you'd like me to run.

yes, a very simple test:

guest$ dd if=/dev/zero bs=1M count=20 | ssh host dd of=/dev/null
guest$ ssh host dd if=/dev/zero bs=1M count=20 | dd of=/dev/null

and since I suspect that the disk io suffers too but due to
caching, maybe reading just a bit off the disk device might be an
interesting test:

  dd if=/dev/vda of=/dev/zero bs=1M count=1000

cheers
tobi


> Michael.
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>

-- 
Tobi Oetiker, OETIKER+PARTNER AG, Aarweg 15 CH-4600 Olten, Switzerland
www.oetiker.ch tobi at oetiker.ch +41 62 775 9902