Re: [Qemu-devel] slow networking with VM virtio

[Bandan Das]

[Ccing qemu-devel and kvm]

"Boylan, Ross" <address@hidden> writes:

> Running a Windows 7 VM under KVM, with virtio drivers, the networking was so 
> slow as to be non-functional.
> As suggested in comment 11 of  
> https://bugzilla.redhat.com/show_bug.cgi?id=855640, I did ethtool -K eth1 gro 
> off and speeds got much better, ~150Mb/s, although using speedtest.net it was 
> unable to connect to the server for the upload test.
>
> However, ssh in to the host machine, or to linux VM's running on the same 
> host, became extremely erratic (prone to dropped connections) and slow after 
> making these changes.  I was connected via sshuttle for VPN.
>
> Does anyone have any suggestions?
> I would appreciate a cc.
>
> Thanks.
> Ross Boylan
>
> Details:
> Host is running Debian wheezy on amd64.  Using virt-manager > libvirt > kvm 
> and bridged networking.
> Linux markov00 3.2.0-4-amd64 #1 SMP Debian 3.2.65-1+deb7u2 x86_64 GNU/Linux
> Here's one of the network specifications for libvirt:
>     <interface type='direct'>
>       <mac address='52:54:00:61:xxxx'/>
>       <source dev='eth1' mode='vepa'/>
>       <model type='virtio'/>
>       <address type='pci' domain='0x0000' bus='0x00' slot='0x03' 
> function='0x0'/>
>    </interface>
>
> The Windows drivers came from 
> http://alt.fedoraproject.org/pub/alt/virtio-win/latest/images/virtio-win-0.1-100.iso
>  in the 32 bit windows 7 directory of the iso (host is 64 bit, as is the 
> emulated machine; Windows 7 is 32 bit). --
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