2014-11-10 13:45 GMT+01:00 Akilesh K <akilesh1...@gmail.com>: > Hi Alberto, > May I know the flavor and image you were using to do this test. TSO seems > to be a method that moves the process of tcp segmentation off to the nic > card. > > Hi Akilesh,
I was using m1.tiny flavor with 512MiB of RAM and 1 vCPU for all the previous tests. Testing now with m1.smaill (2048 MiB of RAM and 1 vCPU) there is a slight increase in the bandwidth between the instance and its router: ~ 300Kbits/sec. The increase is more evident using m1.medium (4096 MiB of RAM and 2 vCPUs) where a bandwidth ~ 700 Kbits/sec is achieved. In both cases bandwidth of 700-800 Mbits/sec are measured turning off TSO: ubuntu@test4g:~$ iperf -c 10.0.0.1 ------------------------------------------------------------ Client connecting to 10.0.0.1, TCP port 5001 TCP window size: 85.0 KByte (default) ------------------------------------------------------------ [ 3] local 10.0.0.17 port 50855 connected with 10.0.0.1 port 5001 [ ID] Interval Transfer Bandwidth [ 3] 0.0-11.9 sec 1.00 MBytes 704 Kbits/sec ubuntu@test4g:~$ sudo ethtool -K eth0 tso off ubuntu@test4g:~$ iperf -c 10.0.0.1 ------------------------------------------------------------ Client connecting to 10.0.0.1, TCP port 5001 TCP window size: 85.0 KByte (default) ------------------------------------------------------------ [ 3] local 10.0.0.17 port 50856 connected with 10.0.0.1 port 5001 [ ID] Interval Transfer Bandwidth [ 3] 0.0-10.0 sec 938 MBytes 786 Mbits/sec > I believe in OpenStack the nic is a tap interface that kvm attaches your > instance to and hence you have offloaded the task of segmenting to the host > cpu now ( I am only guessing, not sure). > > Yes. KVM is using tap interfaces with virtio driver. I would like to know if this is the case and using a better flavor and > image would offer you better results without tinkering with the interface. > > Images used are Ubuntu Trusty downloaded from http://images.ubuntu.com/trusty/current and a Debian Wheezy tested previously in another private cloud. No significant differences were found using Ubuntu or Debian images. Thanks Akilesh! Alberto
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