Proposed patch, convert IFQ_MAXLEN to kernel tunable...

[John-Mark Gurney]

George V. Neville-Neil wrote this message on Tue, Sep 23, 2008 at 15:29 -0400:
> It turns out that the last time anyone looked at this constant was
> before 1994 and it's very likely time to turn it into a kernel
> tunable.  On hosts that have a high rate of packet transmission
> packets can be dropped at the interface queue because this value is
> too small.  Rather than make a sweeping code change I propose the
> following change to the macro and updating a couple of places in the
> IP and IPv6 stacks that were using this macro to set their own global
> variables.

The better solution is to resurrect rwatson's patch that eliminates the
interface queue, and does direct dispatch to the ethernet driver..
Usually the driver has a queue of 512 or more packets already, so putting
them into a second queue doesn't provide much benefit besides increasing
the amount of locking necessary to deliver packets...

-- 
  John-Mark Gurney				Voice: +1 415 225 5579

     "All that I will do, has been done, All that I have, has not."