Hi, Barak, Hope the following info can help you
1. HOST: <http://git.linaro.org/people/christoffer.dall/linux-kvm-arm.git> http://git.linaro.org/people/christoffer.dall/linux-kvm-arm.git branch: v3.10-arndale config: arch/arm/configs/exynos5_arndale_defconfig dtb: arch/arm/boot/dts/exynos5250-arndale.dtb rootfs: Ubuntu 13.10 GUEST: Official 3.12 config: arch/arm/configs/vexpress_defconfig with virtio-devices enabled dtb: arch/arm/boot/dts/vexpress-v2p-ca15-tc1.dtb rootfs: Ubuntu 12.04 2. We are still developing it in progress and will try to open source asap. The main purpose of that patch is to introduce the ioeventfd into kvm-arm 3. as mentioned in 1. 4. qemu-1.6.0 5. We ported part of guest/host notifiers of virtio-pci to virtio-mmio 6. /usr/bin/qemu-system-arm -enable-kvm -kernel /root/nfs/zImage -m 128 --machine vexpress-a15 -cpu cortex-a15 -drive file=/root/nfs/guest-1G-precise-vm1.img,id=virtio-blk,if=none,cache=none -device virtio-blk-device,drive=virtio-blk -append "earlyprintk=ttyAMA0 console=ttyAMA0 root=/dev/vda rw ip=192.168.101.101::192.168.101.1:vm1:eth0:off --no-log" -dtb /root/nfs/vexpress-v2p-ca15-tc1.dtb --nographic -chardev socket,id=mon,path=/root/vm1.monitor,server,nowait -mon chardev=mon,id=monitor,mode=readline -device virtio-net-device,netdev=net0,mac="52:54:00:12:34:01" -netdev type=tap,id=net0,script=/root/nfs/net.sh,downscript=no,vhost=off vhost-net could be truned on by changing the last parameter vhost=on. -- Ying-Shiuan Pan, H Div., CCMA, ITRI, TW ---- Best Regards, 潘穎軒Ying-Shiuan Pan 2014/1/13 Barak Wasserstrom <wba...@gmail.com> > Ying-Shiuan Pan, > Your experiments with arndale Exynos-5250 board can help me greatly and i > would really appreciate if you share with me the following information: > 1. Which Linux kernel did you use for the host and for the guest? > 2. Which Linux kernel patches did you use for KVM? > 3. Which config files did you use for both the host and guest? > 4. Which QEMU did you use? > 5. Which QEMU patches did you use? > 6. What is the exact command line you used for invoking the guest, with > and without vhost-net? > > Many thanks in advance! > > Regards, > Barak > > > > On Mon, Jan 13, 2014 at 5:47 AM, Ying-Shiuan Pan <yingshiuan....@gmail.com > > wrote: > >> Hi, Barak, >> >> We've tried vhost-net in kvm-arm on arndale Exynos-5250 board (it >> requires some patches in qemu and kvm, of course). It works (without irqfd >> support), however, the performance does not increase much. The throughput >> (iperf) of virtio-net and vhost-net are 93.5Mbps and 93.6Mbps respectively. >> I thought the result are because both virtio-net and vhost-net almost >> reached the limitation of 100Mbps Ethernet. >> >> The good news is that we even ported vhost-net in our kvm-a9 hypervisor >> (refer: >> http://academic.odysci.com/article/1010113020064758/evaluation-of-a-server-grade-software-only-arm-hypervisor), >> and the throughput of vhost-net on that platform (with 1Gbps Ethernet) >> increased from 323Mbps to 435Mbps. >> >> -- >> Ying-Shiuan Pan, >> H Div., CCMA, ITRI, TW >> >> >> ---- >> Best Regards, >> 潘穎軒Ying-Shiuan Pan >> >> >> 2014/1/13 Peter Maydell <peter.mayd...@linaro.org> >> >>> On 12 January 2014 21:49, Barak Wasserstrom <wba...@gmail.com> wrote: >>> > Thanks - I got virtio-net-device running now, but performance is >>> terrible. >>> > When i look at the guest's ethernet interface features (ethtool -k >>> eth0) i >>> > see all offload features are disabled. >>> > I'm using a virtual tap on the host (tap0 bridged to eth3). >>> > On the tap i also see all offload features are disabled, while on br0 >>> and >>> > eth3 i see the expected offload features. >>> > Can this explain the terrible performance i'm facing? >>> > If so, how can this be changed? >>> > If not, what else can cause such bad performance? >>> > Do you know if vhost_net can be used on ARM Cortex A15 host/guest, even >>> > though the guest doesn't support PCI & MSIX? >>> >>> I have no idea, I'm afraid. I don't have enough time available to >>> investigate performance issues at the moment; if you find anything >>> specific you can submit patches... >>> >>> thanks >>> -- PMM >>> >>> >> >
