Hello, I'm setting nVMX environment and observing poor network performance from L2 guest to L0 or any physical PC on the same network if L1 and L2 are running with vhost=on. My configuration is L0 - 4.11-rc8 from Fedora 26, Xeon 2330v4 with x2apic and apicv enabled L1 - 4.11-rc8 from Fedora 26, network model virtio with vhost on L2 - Ubuntu 16.10, network model virtio with vhost on L2 - Windows 2012R2 with virtio drivers 135-1 I run a couple of tests with iperf3 and the results are: L0 --> L1 is 23-30 Gbit L1 --> L2 is the same L1 --> L2 is the same L2 --> L1 is the same L0 --> L2 also shows the same performance Connecting to host 10.0.212.179, port 5201 [ 4] local 10.0.212.29 port 46254 connected to 10.0.212.179 port 5201 [ ID] Interval Transfer Bandwidth Retr Cwnd [ 4] 0.00-1.00 sec 2.96 GBytes 25.5 Gbits/sec 12 1.66 MBytes [ 4] 1.00-2.00 sec 3.05 GBytes 26.2 Gbits/sec 19 2.11 MBytes [ 4] 2.00-3.00 sec 3.31 GBytes 28.5 Gbits/sec 22 2.39 MBytes [ 4] 3.00-4.00 sec 3.40 GBytes 29.2 Gbits/sec 86 2.48 MBytes [ 4] 4.00-5.00 sec 3.37 GBytes 28.9 Gbits/sec 36 2.54 MBytes [ 4] 5.00-6.00 sec 3.43 GBytes 29.5 Gbits/sec 43 2.67 MBytes [ 4] 6.00-7.00 sec 3.38 GBytes 29.0 Gbits/sec 61 2.77 MBytes [ 4] 7.00-8.00 sec 2.80 GBytes 24.1 Gbits/sec 14 2.78 MBytes [ 4] 8.00-9.00 sec 3.23 GBytes 27.8 Gbits/sec 37 2.83 MBytes [ 4] 9.00-10.00 sec 3.37 GBytes 28.9 Gbits/sec 45 2.96 MBytes - - - - - - - - - - - - - - - - - - - - - - - - - [ ID] Interval Transfer Bandwidth Retr [ 4] 0.00-10.00 sec 32.3 GBytes 27.7 Gbits/sec 375 sender [ 4] 0.00-10.00 sec 32.3 GBytes 27.7 Gbits/sec receiver But results for L2-->L0 are: Accepted connection from 10.0.212.179, port 54096 [ 5] local 10.0.212.29 port 5201 connected to 10.0.212.179 port 54098 [ ID] Interval Transfer Bandwidth [ 5] 0.00-1.00 sec 14.3 MBytes 120 Mbits/sec [ 5] 1.00-2.00 sec 0.00 Bytes 0.00 bits/sec [ 5] 2.00-3.00 sec 0.00 Bytes 0.00 bits/sec [ 5] 3.00-4.00 sec 0.00 Bytes 0.00 bits/sec [ 5] 4.00-5.00 sec 0.00 Bytes 0.00 bits/sec And I have to reset network on L2. Sometimes test completed successfully without the need to restart network. If I run Windows 2012R2 as L2 guest I can see that network doesn't have any packets for 5 seconds, then some packets are passed, 5 seconds idle and so one. I also tried different NIC combinations for L1 and L2: L1 vmxnet3 L2 vmxnet3 - OK L1 virtio-vhost L2 virtio - OK L1 virtio L2 virtio-vhost - OK So the issue occurs only when L1 and L2 are running with virtio-vhost and when traffic goes from L2 to L0 or other physical PC. Thanks, Gleb
