doubt on auto tuning in 2.4 kernels

doubt on auto tuning in 2.4 kernels

[Akarapu Mahesh]

Hi,
Does anybody know if auto tuning can be turned off in 2.4 kernels. If yes
can some body tell me how to do so. Seems like Auto tuning of socket buffers
is overriding my large buffer settings.
Any help in this regard would be appreciated.

thanks
mahi


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Re: doubt on auto tuning in 2.4 kernels

[Eric Weigle]

> Hi,
> Does anybody know if auto tuning can be turned off in 2.4 kernels. If yes
> can some body tell me how to do so. Seems like Auto tuning of socket buffers
> is overriding my large buffer settings.
> Any help in this regard would be appreciated.

It can't be turned off. It is a way of managing non-swappable kernel memory
and if you are in memory pressure, then you may not get 'ideal' buffers.

There are a couple things you *can* do, though; take a look at
Documentation/networking/ip-sysctl.txt in the kernel source. In particular,
tcp_wmem and tcp_rmem. It's not a good idea to set min and max the
same, but if you make your default the 'ideal' and the min/max slightly
less/more you should get good results.

Also look at your settings in /proc/sys/net/core/[rw]mem_[max|default].

Here are a couple of tuning links I've found useful:

	http://www.psc.edu/networking/perf_tune.html#Linux
	http://www-didc.lbl.gov/tcp-wan.html
 
-Eric

--
--------------------------------------------
 Eric H. Weigle   CCS-1, RADIANT team
 ehw@lanl.gov     Los Alamos National Lab
 (505) 665-4937   http://home.lanl.gov/ehw/
--------------------------------------------