On Thu, 2012-05-31 at 14:51 +0200, Jesper Dangaard Brouer wrote:

On Thu, 2012-05-31 at 00:40 +0200, Jesper Dangaard Brouer wrote:

quoted

That seems like a very unlikely situation, which we perhaps should
neglect as we are under SYN attack.

I will test the attack vector, if we instead of dropping the reqsk,
fall back into the slow locked path.

I can provoke this attack vector, and performance is worse, if not
dropping the reqsk early.

Generator SYN flood at 750Kpps, sending false retransmits mixture.

- With early drop: 406 Kpps
- With return to locked processing: 251 Kpps

Its still better than the approx 150Kpps, without any patches.

How many different IP addresses are used by your generator ?

Or maybe you disabled IP route cache ?