linux KVM guests network performance is slower than host

i have a KVM linux based virtual machines, as the network performance of the host is running perfect with 1GB/s(in internal network) and using iperf tools it show that the network is running perfect in host , but guests is slow network performance as iperf result was so strange as it is not 100MB/s and is not 1GB/s its range between 350 and 500MB/s maximum, and this is result of using iperf command (iperf -c servername -P 15)

[ ID] Interval Transfer Bandwidth
[ 17] 0.0-10.0 sec 68.6 MBytes 57.5 Mbits/sec
[ ID] Interval Transfer Bandwidth
[ 4] 0.0-10.0 sec 18.6 MBytes 15.5 Mbits/sec
[ ID] Interval Transfer Bandwidth
[ 5] 0.0-10.0 sec 61.9 MBytes 51.9 Mbits/sec
[ ID] Interval Transfer Bandwidth
[ 11] 0.0-10.0 sec 16.0 MBytes 13.4 Mbits/sec
[ ID] Interval Transfer Bandwidth
[ 10] 0.0-10.0 sec 24.3 MBytes 20.4 Mbits/sec
[ ID] Interval Transfer Bandwidth
[ 15] 0.0-10.0 sec 20.2 MBytes 16.9 Mbits/sec
[ ID] Interval Transfer Bandwidth
[ 12] 0.0-10.0 sec 30.2 MBytes 25.3 Mbits/sec
[ ID] Interval Transfer Bandwidth
[ 3] 0.0-10.0 sec 36.2 MBytes 30.3 Mbits/sec
[ ID] Interval Transfer Bandwidth
[ 8] 0.0-10.0 sec 23.6 MBytes 19.8 Mbits/sec
[ ID] Interval Transfer Bandwidth
[ 9] 0.0-10.0 sec 24.2 MBytes 20.3 Mbits/sec
[ ID] Interval Transfer Bandwidth
[ 14] 0.0-10.0 sec 31.0 MBytes 25.9 Mbits/sec
[ ID] Interval Transfer Bandwidth
[ 7] 0.0-10.0 sec 16.6 MBytes 13.9 Mbits/sec
[ ID] Interval Transfer Bandwidth
[ 6] 0.0-10.0 sec 18.8 MBytes 15.7 Mbits/sec
[ ID] Interval Transfer Bandwidth
[ 13] 0.0-10.0 sec 13.3 MBytes 11.2 Mbits/sec
[ ID] Interval Transfer Bandwidth
[ 16] 0.0-10.0 sec 29.6 MBytes 24.8 Mbits/sec
[SUM] 0.0-10.0 sec 433 MBytes 363 Mbits/sec

i tested different network models and the best result was with the virtio model any one please can help to get the full performance of network and be 1 GB/s

1 Answer

try and stop iptables and run your test again, I have seen a miss configured "mingle table" can have similar effects on your kvm guests.

/etc/init.d/iptables off

5

Your Answer

Sign up or log in

Sign up using Google Sign up using Facebook Sign up using Email and Password Submit

Post as a guest

Post Your Answer Discard

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy