On Wed, 2012-06-27 at 10:02 +0200, Eric Dumazet wrote:

On Wed, 2012-06-27 at 09:54 +0200, Jesper Dangaard Brouer wrote:

quoted

Well, that would lead to parallel SYN processing, wouldn't it?

I think we already discussed of the current issues of current code.

Telling people to spread SYN to several cpus is a good way to have a
freeze in case of synflood, because 15 cpus are busy looping while one
is doing progress.

Yes, that was also what I experienced (contention on spinlock), and then
tried to address it with my parallel SYN cookie patches, and it worked
amazing well...

Thats why Intel felt the need of a hardware filter to direct all SYN
packets on a single queue.

It works because we have a spinlock problem in the code... Perhaps, they
did it, because we have have locking/contention problem, not the other
way around ;-)  How about fixing the code instead? ;-)))