skb size

Oommen Thomas (
Thu, 21 May 1998 00:48:06 +0530 (IST)

Hi all,

We are facing a major throughput problem on our ftp-site under
slackware linux 2.0.30.

Testing showed that this may be mainly due to the OS (kernel) limitations.

UDP services like tftp/rcp as well as SMTP/UUCP give very good throughput,

The 'skbuff' settings in 'tcp.c' is said to be hardcoded and fails under
heavy load. The following line is a typical case in this.

copy = min(sk->mss - tcp_size, seglen);

Is there a real problem in the kernel?
Is this solved in newer versions?
Is a patch available for the problem?

The network consultant is even suggesting of replacing the 'free' linux
with a better & powerful 'real' unix with a 'full' commercial
implementation of TCP, which will not drop packets on heavy load.

The advice we received (which we find hard to buy) is that a free OS
like Linux must not be used for Production servers as the kernel lacks lot
of TCP functionalities.

Any hints (to help save linux's as well as our prestige) will be greatly

Regards, Imagine Technologies
Oommen 16,Shaffee Mohammed Road
Rutland Gate
eMail: Chennai 600 006 INDIA Voice : 91-44-8211031/733/734/796
Fax : 91-44-8225341

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