I agree, but since you are saying this is in open stack environ, the Guest's parameters gets supplied through different input files for different type of Guests, better to check once. -----Original Message----- From: JR [mailto:botemout@xxxxxxxxx] Sent: Thursday, May 15, 2014 11:33 PM To: Venkateswara Rao Nandigam; kvm@xxxxxxxxxxxxxxx Subject: Re: Poor performance with virtio network driver on windows 2008 R2 on KVM Yes, thank you, Venkateswara, it is vhost=on is present. This is something specific to driver in windows since, in linux it performs very well. On 5/15/2014 1:41 PM, Venkateswara Rao Nandigam wrote: > One more important thing is to make sure you launch vhost thread for your virtio nic, as part of Guest instantiation. There will be a parameter "vhost=on" in Guest instantiation command line. > > -----Original Message----- > From: kvm-owner@xxxxxxxxxxxxxxx [mailto:kvm-owner@xxxxxxxxxxxxxxx] On > Behalf Of Venkateswara Rao Nandigam > Sent: Thursday, May 15, 2014 10:20 AM > To: JR; kvm@xxxxxxxxxxxxxxx > Subject: RE: Poor performance with virtio network driver on windows > 2008 R2 on KVM > > Try TSO offload on Guest Virtio interface > > And try passthrough interface mode at Host Level for this Guest Virtio > Interface > > Thanks, > Venkatesh > > -----Original Message----- > From: kvm-owner@xxxxxxxxxxxxxxx [mailto:kvm-owner@xxxxxxxxxxxxxxx] On > Behalf Of JR > Sent: Wednesday, May 14, 2014 9:07 PM > To: kvm@xxxxxxxxxxxxxxx > Subject: Poor performance with virtio network driver on windows 2008 > R2 on KVM > > Greetings all, > > Though I don't believe that this is KVM problem per se, I'm seeing very poor network performance when using windows 2008R2 KVM instances with the virtio driver when on a 10G network. iperf results show linux VMs getting close to wire speeds, while windows only does about 1.3Gb/sec. > > I've tried a number of tcp settings (chimney, etc...) as recommended by some google searches but nothing has helped. > > Does anyone have any advice? > > Thanks much, > JR > > > -- > Your electronic communications are being monitored; strong encryption > is an answer. My public key > <http://pgp.mit.edu:11371/pks/lookup?op=get&search=0x4F08C504BD634953> > -- > To unsubscribe from this list: send the line "unsubscribe kvm" in the > body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at > http://vger.kernel.org/majordomo-info.html > -- > To unsubscribe from this list: send the line "unsubscribe kvm" in the > body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at > http://vger.kernel.org/majordomo-info.html > -- Your electronic communications are being monitored; strong encryption is an answer. My public key <http://pgp.mit.edu:11371/pks/lookup?op=get&search=0x4F08C504BD634953> -- To unsubscribe from this list: send the line "unsubscribe kvm" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html