Re: TCP receiver's window calculation problem

[John Heffner <jheffner@xxxxxxx>]

On Thu, 24 Jun 2004, Cheng Jin wrote:

> I think having a default limit on tcp memory is acceptable to prevent DoS,
> but when a user increases the memory limit by explicitly setting tcp_rmem,
> that should take effect.  The code itself shouldnt pose any limit like it
> does now.

The core of the problem is that you are describing a truesize of each skb
at about 16k, but each of those only contains < 1500 bytes of payload.
You are wasting 90% of your socket memory.  Announcing a 3 MB window with
a 30 MB socket buffer is the right thing to do, from a certain point of
view.  OTOH, it kills performance.


> Actually, I am not clear what that window-calculation algorithm is.  Is it
> recommended by some RFC?

No, it's not standard.  I'm not sure who wrote this code.

  -John