Re: [PATCH] USAGI IPsec

On Sat, 12 Oct 2002 04:41:37 -0700 (PDT)
"David S. Miller" [off-list ref] wrote:

   From: bert hubert [off-list ref]
   Date: Sat, 12 Oct 2002 13:17:59 +0200

   On Fri, Oct 11, 2002 at 07:41:08PM -0700, David S. Miller wrote:
   > We believe that the whole SPD/SAD mechanism should move
   > eventually to a top-level flow cache shared by ipv4 and
   > ipv6.
   
   Is this the proposed stacked route system?

Yes, for output mostly.

Also the idea Alexey and I have to move towards a small
efficient flow cache shared by IPv4/IPv6 plays into this
as well.  There are changesets on their way to Linus tonight
which moves ipv4 over to using ipv6's "struct flowi" from
include/net/flow.h as the routing lookup key.

The initial ipsec is intended to be simple, singly linked
lists for the spd/sad databases etc.  Making the feature
freeze is pretty important right now, full blown flow cache
is just performance improvement :)

Huhu!
Just a word on this one: I recently came across some heavy performance problem
regarding a setup with about 225 000 routes. It looked as if TCP experienced a
tremendous slowdown to about 50 KBytes/sec throughput, whereas UDP worked
pretty much normal. This was a 2.2.19 kernel with equal-cost-multipath enabled
and large routing-tables enabled.
The reason I am writing this is: please keep in mind situations like this with
several hundred thousands of routes in one box. This is a familiar setup for
the routing guys - and not a "just" case ;-)
Thanks for lending an ear.
-- 
Regards,
Stephan