Re: Is kernel 2.6.11 adjust tcp_max_syn_backlog incorrectly?

Skywind
2005-06-07T00:46:42Z

Any one know the reason?

I think the subject may change to
"Is kernel 2.6.11 havn't set /proc network variable"
or
"Kernel 2.6.11 havn't set /proc network variable correctly by mem size"

> Is kernel 2.6.11 adjust tcp_max_syn_backlog incorrectly?
>
> Test Backgroud:
> CPU: Intel P4
> Mem: 512Mb
> The /etc/sysctl.conf and other haven't touch anything.
>
> I found a strange question: when I use kernel 2.6.11, the value of
> /proc/sys/net/ipv4/tcp_max_syn_backlog is 256,
> while kernel 2.6.10 on same computer the value is 1024.
>
> So I check the net/ipv4/[tcp.c, tcp_ipv4.c] and know when Mem >= 256Mb
> the tcp_max_syn_backlog will be set to 1024,
> but it is 256 in my test above.

> Some other variables that should be adjust all together with
> tcp_max_syn_backlog are:
> ip_local_port_range
> tcp_max_tw_buckets
> tcp_max_orphans
> But they don't be adjust to correctly value(refer to net/ipv4/tcp.c) all.
>
> It seems that kernel don't adjust these value automatic, is this a bug?
>
> I guess the mechanism of tcp.c in 2.6.11 have some changes(between
> 2.6.10), and it conduce to this result,
> Is this guess correctly?

> Xu Gang (Skywind)
> 2005/06/06