[ovs-discuss] [help]Question about tcp higher retansmition rate during iperf test

txfh2007 txfh2007 at aliyun.com
Thu Apr 4 09:48:30 UTC 2019


Hi all:
    I'm testing ovs-dpdk performance. the test environment is as below: VM1(2u2g)  and VM2(2u2g) on same host, image is centos 7.2, iperf test shows high tcp retransmition rate as follows. But when I  use native-ovs in the same environment,  the retransmition rate is under 100.
   So what should I  do to Reduce retransmission rate ?  I guess the kernel parameter should be adjusted when using dpdk-ovs ?

Thanks for help 
Timo
 
dpdk-ovs:
[  4] 72.00-73.00  sec   573 MBytes 4.81 Gbits/sec  1206    197 KBytes       
[  4] 73.00-74.00  sec   559 MBytes 4.70 Gbits/sec  1287    361 KBytes       
[  4] 74.00-75.00  sec   555 MBytes 4.66 Gbits/sec  968    430 KBytes       
[  4] 75.00-76.00  sec   563 MBytes 4.72 Gbits/sec  916    444 KBytes       
[  4] 76.00-77.00  sec   480 MBytes 4.02 Gbits/sec  841    402 KBytes       
[  4] 77.00-77.22  sec  91.5 MBytes 3.50 Gbits/sec  764    173 KBytes
[ ID] Interval           Transfer     Bandwidth       Retr
[  4]   0.00-77.22  sec  41.3 GBytes  4.59 Gbits/sec  76413             sender
[  4]   0.00-77.22  sec  0.00 Bytes  0.00 bits/sec                  receiver

native-ovs:

[ ID] Interval           Transfer     Bandwidth       Retr  Cwnd
[  4]   0.00-1.00   sec  1.07 GBytes  9.22 Gbits/sec    0   2.96 MBytes       
[  4]   1.00-2.00   sec  1.09 GBytes  9.39 Gbits/sec    0   3.02 MBytes       
[  4]   2.00-3.00   sec  1.09 GBytes  9.39 Gbits/sec    0   3.02 MBytes       
[  4]   3.00-4.00   sec  1.09 GBytes  9.39 Gbits/sec    0   3.02 MBytes       
[  4]   4.00-4.45   sec   499 MBytes  9.38 Gbits/sec    0   3.02 MBytes       
- - - - - - - - - - - - - - - - - - - - - - - - -
[ ID] Interval           Transfer     Bandwidth       Retr
[  4]   0.00-4.45   sec  4.84 GBytes  9.35 Gbits/sec    0             sender
[  4]   0.00-4.45   sec  0.00 Bytes  0.00 bits/sec                  receiver





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