Hello Boris, On Thu, 2009-09-10 at 19:31 -0700, Boris Shpolyansky wrote: > Are you referring to actual Ethernet frame size or to TCP message > size? > If the port MTU set to 1500 it will reject Ethernet frames larger than > this size, this has nothing to do with the LRO. > LRO is a TCP offload that improves CPU utilization on the TCP receiver > by combining multiple packets belonging to the same TCP stream to a > single buffer and transferring it to the TCP stack as a single large > packet.
Because the LRO is enabled in device driver level, when it receives multiple tcp fragmentation packets, it will merge to a large packet to deliver to upper layer protocol to process. However, the port1 works well, but not for port2 when LRO enabled. I don't know when the packet drops since I don't have any tool rather than tcpdump. From tcpdump I can see the large packet when I use port1, but I can't see the large packet when I use port2 with LRO enabled. If I disabled LRO, all packets are smaller than 1500 mtu from tcpdump, everything works fine for both ports. I hope it's clear. Thanks Shirley _______________________________________________ general mailing list general@lists.openfabrics.org http://lists.openfabrics.org/cgi-bin/mailman/listinfo/general To unsubscribe, please visit http://openib.org/mailman/listinfo/openib-general
