On Wed, Jan 15, 2014 at 04:56:02PM -0600, Xiaoye Sun wrote: > In the experiment, I change the sending rate of the syn packet and compute > the RTT of each syn and syn-ack pair. However, I found that when the rate > is high, for example, 200 syn pkt per sec, the RTTs usually are much less > than the RTTs of a lower sending rate, for example 50 pkt per sec. > > This result is strange since when the sending rate is high, the controller > and ovs should have more workload. The RTT should not be less than the RTT > in a network having less workload per second...
OVS tries to deal with packets in batches for efficiency. At a low rate, probably each batch contains exactly one packet. As the rate increases, I guess that a batch contains more than one packet, and it's likely that the batches mix up SYNs and SYN-ACKs, possibly reducing the latency. OVS 2.0 and later probably have much better latency because these versions use separate threads dedicated to packet forwarding. _______________________________________________ discuss mailing list [email protected] http://openvswitch.org/mailman/listinfo/discuss
