Re: RE: [network performance question] only ~2Gbps throughputbetweentwo linux guests which are running on the same host via netperf-tTCP_STREAM -m 1400, but xen can ac

Zhang Haoyu
2014-06-06T10:14:56Z

> >> Try Rx/Tx checksum offload on the all the concerned guests of both Hypervisors.
> >>
> >Already ON on both hypervisors, so some other offloadings(e.g. tso, gso) can be supported.
>
> Try Rx/Tx checksum offload "OFF" on the all the concerned guests of both Hypervisors
>
Off Rx/Tx checksum offload on XEN guest, 1.6Gbps achived, tcpdump result on backend vif netdeivce shown that packets' size is 1448, stable.
Off Rx/Tx checksum offload on KVM guest, only ~1Gbps ahchived, tcpdump result on backend tap netdevice shown that packets' size is 1448, stable.

> And While launching the VM in KVM, in command line of virtio interface, you can specify TSO, LRO, RxMergebuf. Try this instead of ethtool interface.
The cuurent qemu command shown as below, and I will change the virtio-net configuration later as your advise,
/usr/bin/kvm -id 8572667846472 -chardev socket,id=qmp,path=/var/run/qemu-server/8572667846472.qmp,server,nowait -mon chardev=qmp,mode=control -vnc :0,websocket,to=200,x509,password -pidfile /var/run/qemu-server/8572667846472.pid -daemonize -name centos6-196.5.5.72 -smp sockets=1,cores=2 -cpu core2duo -nodefaults -vga cirrus -no-hpet -k en-us -boot menu=on,splash-time=8000 -m 4096 -usb -drive file=/sf/data/local/iso/vmtools/virtio_auto_install.iso,if=none,id=drive-ide0,media=cdrom,aio=threads,forecast=disable -device ide-cd,bus=ide.0,unit=0,drive=drive-ide0,id=ide0,bootindex=200 -drive file=/sf/data/local/images/host-f8bc123b3e74/32f49b646d1e/centos6-196.5.5.72.vm/vm-disk-1.qcow2,if=none,id=drive-ide2,cache=directsync,aio=threads,forecast=disable -device ide-hd,bus=ide.1,unit=0,drive=drive-
ide2,id=ide2,bootindex=100 -netdev type=tap,id=net0,ifname=857266784647200,script=/sf/etc/kvm/vtp-bridge,vhost=on,vhostforce=on -device virtio-net-pci,mac=FE:FC:FE:95:EC:A7,netdev=net0,bus=p
ci.0,addr=0x12,id=net0,bootindex=300 -rtc driftfix=slew,clock=rt -global kvm-pit.lost_tick_policy=discard -global PIIX4_PM.disable_s3=1 -global PIIX4_PM.disable_s4=1

-----Original Message-----
From: Zhang Haoyu [mailto:zhanghy@sangfor.com]
Sent: Friday, June 06, 2014 1:26 PM
To: Venkateswara Rao Nandigam; kvm; qemu-devel
Cc: Gleb Natapov; Paolo Bonzini; Michael S.Tsirkin; yewudi
Subject: RE: [network performance question] only ~2Gbps throughput betweentwo linux guests which are running on the same host via netperf -tTCP_STREAM -m 1400, but xen can ac