On 03/16/2015 12:37 PM, Jerry Jerry wrote: > Hello everyone, > > We have found a very strange behavior where the transfer is > particularly slower when sending data to a socket connecting ports on > the same host, but rather faster to the socket connecting ports on > different host. /proc/net/sctp/assoc shows that TX_QUEUE of same host > socket buffers a lot of data but RX_QUEUE of the socket on the > receiving side is almost empty. On the contrary, both TX_QUEUE and > RX_QUEUE are almost empty for those sockets connecting different > hosts. > > We first thought this might because the processing difference between > local and remote hosts, but the problem remains the same even for a > symmetric case where both hosts send same messages to both its own > local and remote receiver, and receive messages via different local > and remote connections. In our opinion, the data transfer should be > faster or at least the same when sending to a socket connecting local > ports. > > This problem particularly occurs when the message size is small, but > playing with SCTP NODELAY option doesn't help. This is mostly likely due to the congestion window not being able to grow because the loopback mtu is higher then amount of queued data. You could try tweaking the loopback MTU to see if it changes things.. -vlad > > I'm not sure if I may have missed anything, but any comments to shed > lights on this, or suggestions to tune would be appreciated very much! > > Regards, > Jerry > -- > To unsubscribe from this list: send the line "unsubscribe linux-sctp" in > the body of a message to majordomo@xxxxxxxxxxxxxxx > More majordomo info at http://vger.kernel.org/majordomo-info.html > -- To unsubscribe from this list: send the line "unsubscribe linux-sctp" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
