我正在使用iperf3 verson 3.0.11来测量两个虚拟机之间UDPstream的吞吐量。 虚拟机通过OpenStack部署。 在物理主机中，一个位于布拉迪斯拉发，另一个位于卢布尔雅那。
networking方面，每台物理主机都有一个1Gbit的网卡，虚拟机通过pci_passthrough进行连接，从而可以完全访问网卡。
iperf服务器显示以下输出：
root@lju:/home/gts# iperf3 -s -V iperf 3.0.11 Linux lju 3.13.0-37-generic #64-Ubuntu SMP Mon Sep 22 21:28:38 UTC 2014 x86_64 x86_64 x86_64 GNU/Linux ----------------------------------------------------------- Server listening on 5201 ----------------------------------------------------------- Time: Fri, 15 Jan 2016 12:16:20 GMT Accepted connection from 172.16.0.78, port 40774 Cookie: bra.1452860180.557437.6c142f196ae2a4 [ 5] local 172.16.0.80 port 5201 connected to 172.16.0.78 port 57847 Starting Test: protocol: UDP, 1 streams, 8192 byte blocks, omitting 0 seconds, 10 second test iperf3: OUT OF ORDER - incoming packet = 70 and received packet = 97 AND SP = 5 iperf3: OUT OF ORDER - incoming packet = 71 and received packet = 97 AND SP = 5 iperf3: OUT OF ORDER - incoming packet = 72 and received packet = 99 AND SP = 5 iperf3: OUT OF ORDER - incoming packet = 14 and received packet = 123 AND SP = 5 iperf3: OUT OF ORDER - incoming packet = 15 and received packet = 125 AND SP = 5 iperf3: OUT OF ORDER - incoming packet = 78 and received packet = 137 AND SP = 5 iperf3: OUT OF ORDER - incoming packet = 79 and received packet = 137 AND SP = 5 iperf3: OUT OF ORDER - incoming packet = 80 and received packet = 139 AND SP = 5 iperf3: OUT OF ORDER - incoming packet = 82 and received packet = 172 AND SP = 5 iperf3: OUT OF ORDER - incoming packet = 83 and received packet = 173 AND SP = 5 iperf3: OUT OF ORDER - incoming packet = 65 and received packet = 175 AND SP = 5 iperf3: OUT OF ORDER - incoming packet = 66 and received packet = 176 AND SP = 5 iperf3: OUT OF ORDER - incoming packet = 67 and received packet = 177 AND SP = 5 iperf3: OUT OF ORDER - incoming packet = 84 and received packet = 177 AND SP = 5 iperf3: OUT OF ORDER - incoming packet = 86 and received packet = 198 AND SP = 5 iperf3: OUT OF ORDER - incoming packet = 18 and received packet = 203 AND SP = 5 iperf3: OUT OF ORDER - incoming packet = 19 and received packet = 205 AND SP = 5 iperf3: OUT OF ORDER - incoming packet = 22 and received packet = 270 AND SP = 5 iperf3: OUT OF ORDER - incoming packet = 23 and received packet = 273 AND SP = 5 iperf3: OUT OF ORDER - incoming packet = 38 and received packet = 349 AND SP = 5 iperf3: OUT OF ORDER - incoming packet = 39 and received packet = 350 AND SP = 5 iperf3: OUT OF ORDER - incoming packet = 40 and received packet = 350 AND SP = 5 iperf3: OUT OF ORDER - incoming packet = 41 and received packet = 350 AND SP = 5 iperf3: OUT OF ORDER - incoming packet = 47 and received packet = 412 AND SP = 5 iperf3: OUT OF ORDER - incoming packet = 48 and received packet = 412 AND SP = 5 iperf3: OUT OF ORDER - incoming packet = 49 and received packet = 412 AND SP = 5 iperf3: OUT OF ORDER - incoming packet = 50 and received packet = 414 AND SP = 5 iperf3: OUT OF ORDER - incoming packet = 55 and received packet = 490 AND SP = 5 iperf3: OUT OF ORDER - incoming packet = 56 and received packet = 490 AND SP = 5 iperf3: OUT OF ORDER - incoming packet = 57 and received packet = 490 AND SP = 5 iperf3: OUT OF ORDER - incoming packet = 60 and received packet = 541 AND SP = 5 iperf3: OUT OF ORDER - incoming packet = 61 and received packet = 541 AND SP = 5 iperf3: OUT OF ORDER - incoming packet = 62 and received packet = 541 AND SP = 5 iperf3: OUT OF ORDER - incoming packet = 63 and received packet = 541 AND SP = 5 [ ID] Interval Transfer Bandwidth Jitter Lost/Total Datagrams [ 5] 0.00-1.00 sec 105 MBytes 880 Mbits/sec 0.086 ms 141304/154697 (91%) [ 5] 1.00-2.00 sec 114 MBytes 956 Mbits/sec 0.142 ms 164060/178642 (92%) [ 5] 2.00-3.00 sec 114 MBytes 956 Mbits/sec 0.083 ms 165925/180507 (92%) [ 5] 3.00-4.00 sec 114 MBytes 956 Mbits/sec 0.090 ms 164512/179094 (92%) [ 5] 4.00-5.00 sec 114 MBytes 956 Mbits/sec 0.107 ms 166389/180972 (92%) [ 5] 5.00-6.00 sec 114 MBytes 956 Mbits/sec 0.079 ms 159459/174041 (92%) [ 5] 6.00-7.00 sec 114 MBytes 956 Mbits/sec 0.084 ms 168138/182720 (92%) [ 5] 7.00-8.00 sec 114 MBytes 956 Mbits/sec 0.098 ms 169098/183680 (92%) [ 5] 8.00-9.00 sec 114 MBytes 956 Mbits/sec 0.101 ms 166463/181046 (92%) [ 5] 9.00-10.00 sec 114 MBytes 956 Mbits/sec 0.097 ms 168547/183128 (92%) [ 5] 10.00-10.15 sec 16.6 MBytes 952 Mbits/sec 0.076 ms 23353/25473 (92%) - - - - - - - - - - - - - - - - - - - - - - - - - Test Complete. Summary Results: [ ID] Interval Transfer Bandwidth Jitter Lost/Total Datagrams [ 5] 0.00-10.15 sec 13.8 GBytes 11.7 Gbits/sec 0.076 ms 1657248/1804000 (92%) [SUM] 0.0-10.1 sec 1657248 datagrams received out-of-order CPU Utilization: local/receiver 11.9% (1.3%u/10.6%s), remote/sender 44.5% (4.0%u/40.5%s) iperf 3.0.11 Linux lju 3.13.0-37-generic #64-Ubuntu SMP Mon Sep 22 21:28:38 UTC 2014 x86_64 x86_64 x86_64 GNU/Linux 客户端显示这个输出：
root@bra:/home/gts# iperf3 -u -c 172.16.0.80 -b 0 -V iperf 3.0.11 Linux bra 3.13.0-37-generic #64-Ubuntu SMP Mon Sep 22 21:28:38 UTC 2014 x86_64 x86_64 x86_64 GNU/Linux Time: Fri, 15 Jan 2016 12:16:20 GMT Connecting to host 172.16.0.80, port 5201 Cookie: bra.1452860180.557437.6c142f196ae2a4 [ 4] local 172.16.0.78 port 57847 connected to 172.16.0.80 port 5201 Starting Test: protocol: UDP, 1 streams, 8192 byte blocks, omitting 0 seconds, 10 second test [ ID] Interval Transfer Bandwidth Total Datagrams [ 4] 0.00-1.00 sec 1.38 GBytes 11.8 Gbits/sec 180260 [ 4] 1.00-2.00 sec 1.37 GBytes 11.7 Gbits/sec 179180 [ 4] 2.00-3.00 sec 1.37 GBytes 11.8 Gbits/sec 179950 [ 4] 3.00-4.00 sec 1.37 GBytes 11.8 Gbits/sec 180030 [ 4] 4.00-5.00 sec 1.37 GBytes 11.7 Gbits/sec 179240 [ 4] 5.00-6.00 sec 1.33 GBytes 11.5 Gbits/sec 174840 [ 4] 6.00-7.00 sec 1.40 GBytes 12.0 Gbits/sec 183040 [ 4] 7.00-8.00 sec 1.40 GBytes 12.1 Gbits/sec 183970 [ 4] 8.00-9.00 sec 1.38 GBytes 11.9 Gbits/sec 180830 [ 4] 9.00-10.00 sec 1.39 GBytes 12.0 Gbits/sec 182660 - - - - - - - - - - - - - - - - - - - - - - - - - Test Complete. Summary Results: [ ID] Interval Transfer Bandwidth Jitter Lost/Total Datagrams [ 4] 0.00-10.00 sec 13.8 GBytes 11.8 Gbits/sec 0.076 ms 1657248/1804000 (92%) [ 4] Sent 1804000 datagrams CPU Utilization: local/sender 44.5% (4.0%u/40.5%s), remote/receiver 11.9% (1.3%u/10.6%s)
首先，与开始测量时传入服务器的“失序”数据包数量不同。 此外，总结显示11.7Gbit / s的带宽，而NIC只能够1Gbit / s。 中间结果在服务器端显示更多的潜力，但在客户端显示相同的exception数字。 通常也有92％的数据报丢失。
有没有人有指示为什么iperf3展示这种行为？