Re: UDP and e1000 : Simple test, little bugs.

From: Ben Greear
Date: Thu Feb 17 2005 - 19:30:42 EST


Vincent Roqueta wrote:
Hello all,

I am working on NFS interoperabiity and I experiment some problems with UDP. The problem appear between the linux 2.6.10rc1 and 2.6.10rc2, and is still present in the last kernel (2.6.11rc3)

With NFSv3:
Client send a 32k file splited into 22 IP fragments. The problem is the server only receive 17 fragments.
More investigation tell me that the server reveive 17 fragments because the client only send 17 IP fragments.

As the NFS client code is exactly the same between the 2.6.10rc1 and 2.6.10rc2 I tried to write a simple UDP client server, to be sure there is no relation between this bug and NFS.

Client create a buffer of X bytes and fill it with the 'A' symbol. Then it write it over a udp socket (sendto).
Server read the first 1024KB sent.

If X is <26000 the write is done with sucess.
Else it fail. (Typicaly for a 32KB size, as for NFS)

Try setting the socket send buffer size larger. By default it's
quite small, and so it may not accept a large UDP frame.

Ben


--
Ben Greear <greearb@xxxxxxxxxxxxxxx>
Candela Technologies Inc http://www.candelatech.com

-
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/