Add the tested-by:) Tested-by: Qian Xu <qian.q.xu at intel.com>
- Test Commit: 608487f3fc96704271c624d0f3fe9d7fb2187aea - OS/Kernel: Fedora 21/4.1.13 - GCC: gcc (GCC) 4.9.2 20141101 (Red Hat 4.9.2-1) - CPU: Intel(R) Xeon(R) CPU E5-2695 v4 @ 2.10 - NIC: Intel(R) Ethernet Controller X710 for 10GbE SFP+ - Total 2 cases, 2 passed, 0 failed. Test Case1: Virtio-net IPV4 fwd performance with mergable=off Summary: Launch the vhost-switch sample, and launch VM with 2 virtio-net devices, let 2 virtio-net run IPV4 fwd, send traffic to the NIC port and let the traffic go through 2 virtio-net devices. Check the performance. Details: 1. Bind one port to igb_uio. 2. Run vhost switch sample with mergeable=0, disable mergeable. taskset -c 18-19 ./examples/vhost/build/vhost-switch -c 0xc0000 -n 4 --huge-dir /mnt/huge --socket-mem 1024,1024 -- -p 0x1 --mergeable 0 --vm2vm 0 3. Launch VM: taskset -c 22-23 \ /root/qemu-versions/qemu-2.6.0/x86_64-softmmu/qemu-system-x86_64 -name vm1 \ -cpu host -enable-kvm -m 2048 -object memory-backend-file,id=mem,size=2048M,mem-path=/mnt/huge,share=on -numa node,memdev=mem -mem-prealloc \ -smp cores=4 -drive file=/home/img/vm1.img \ -chardev socket,id=char0,path=./vhost-net \ -netdev type=vhost-user,id=mynet1,chardev=char0,vhostforce \ -device virtio-net-pci,mac=52:54:00:00:00:01,netdev=mynet1,mrg_rxbuf=on \ -chardev socket,id=char1,path=./vhost-net \ -netdev type=vhost-user,id=mynet2,chardev=char1,vhostforce \ -device virtio-net-pci,mac=52:54:00:00:00:02,netdev=mynet2,mrg_rxbuf=on \ -netdev tap,id=ipvm1,ifname=tap3,script=/etc/qemu-ifup -device rtl8139,netdev=ipvm1,id=net0,mac=00:00:00:00:10:01 \ -vnc :3 -daemonize 4. Set IPV4 fwd rules in VM: virtio1=$1 virtio2=$2 systemctl stop firewalld.service systemctl disable firewalld.service systemctl stop ip6tables.service systemctl disable ip6tables.service systemctl stop iptables.service systemctl disable iptables.service systemctl stop NetworkManager.service echo 1 >/proc/sys/net/ipv4/ip_forward ip addr add 192.168.1.2/24 dev $virtio1 ip neigh add 192.168.1.1 lladdr 00:00:10:00:24:00 dev $virtio1 ip link set dev $virtio1 up ip addr add 192.168.2.2/24 dev $virtio2 ip neigh add 192.168.2.1 lladdr 00:00:10:00:24:01 dev $virtio2 ip link set dev $virtio2 up 5. Send traffic to NIC and see the performance back from virtio2. The performance is back with the patch. Test Case2: Virtio-net IPV4 fwd performance with mergable=on Similar steps, just one feature set is different, set mergable=1 in the vhost-switch sample, then the performance is good as before. -----Original Message----- From: Yuanhan Liu [mailto:yuanhan....@linux.intel.com] Sent: Thursday, July 21, 2016 9:34 AM To: Tan, Jianfeng <jianfeng.tan at intel.com> Cc: dev at dpdk.org; Wang, Zhihong <zhihong.wang at intel.com>; Xu, Qian Q <qian.q.xu at intel.com> Subject: Re: [PATCH v3] examples/vhost: fix perf regression On Thu, Jul 21, 2016 at 12:42:45AM +0000, Jianfeng Tan wrote: > We find significant perfermance drop introduced by below commit, when > vhost example is started with --mergeable 0 and inside vm, kernel > virtio-net driver is used to do ip based forwarding. > > The commit, 859b480d5afd ("vhost: add guest offload setting"), adds > support for VIRTIO_NET_F_GUEST_TSO4 and VIRTIO_NET_F_GUEST_TSO6, in > vhost lib. But inside vhost example, the way to disable tso only > excludes the direction from virtio to vhost, but not the opposite > direction. When mergeable is disabled, it triggers big_packets path of > virtio-net driver to prepare to receive possible big packets with size > of 64K. Because mergeable is off, for each entry of avail ring, virtio > driver uses 19 desc chained together, with one desc pointing to > header, other 18 desc pointing to 4K-sized pages. But QEMU only > creates 256 desc entries for each vq, which results in that only 13 > packets can be received. VM kernel can quickly handle those packets > and go to sleep (HLT). > > As QEMU has no option to set the desc entries of a vq, so here, we > disable VIRTIO_NET_F_GUEST_TSO4 and VIRTIO_NET_F_GUEST_TSO6 with > VIRTIO_NET_F_HOST_TSO4 and VIRTIO_NET_F_HOST_TSO6 when we disable tso > of vhost example, to avoid VM kernel virtio driver go into big_packets > path. > > Fixes: 9fd72e3cbd29 ("examples/vhost: add virtio offload") > > Reported-by: Qian Xu <qian.q.xu at intel.com> > Signed-off-by: Jianfeng Tan <jianfeng.tan at intel.com> > --- > v3: reword commit log. Yes, much better. One minor nit: you forgot to carry the Tested-by from Qian. Acked-by: Yuanhan Liu <yuanhan.liu at linux.intel.com> Thanks. --yliu
