Thanks a lot, vlad, I'll give it a try. Regards, Jerry On Mon, Mar 16, 2015 at 3:24 PM, Vlad Yasevich <vyasevich@xxxxxxxxx> wrote: > 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
