From mboxrd@z Thu Jan 1 00:00:00 1970 From: James Courtier-Dutton Subject: Re: [PATCH 0/2]: Remote softirq invocation infrastructure. Date: Sun, 21 Sep 2008 10:13:47 +0100 Message-ID: <48D6104B.9040304@superbug.co.uk> References: Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Cc: David Miller , dwalker@mvista.com, arjan@infradead.org, linux-kernel@vger.kernel.org, netdev@vger.kernel.org, jens.axboe@oracle.com, steffen.klassert@secunet.com To: Herbert Xu Return-path: In-Reply-To: Sender: linux-kernel-owner@vger.kernel.org List-Id: netdev.vger.kernel.org Herbert Xu wrote: > David Miller wrote: >> receive using multiple RX queues and MSI-X interrupts. It's >> also for things like IPSEC where the per-packet cpu usage >> is so huge (to do the crypto) that it makes sense to even >> split up the work to multiple cpus within the same flow. > > Unfortunately doing this with IPsec is going to be non-trivial > since we still want to maintain packet ordering inside IPsec > and you don't get the inner flow information until you decrypt > the packet. > Why do you have to preserve packet ordering? TCP/IP does not preserve packet ordering across the network. IPSEC uses a sliding window for anti-relay detection precisely because it has to be able to handle out-of-order packets. Sharing the sliding window between CPUs might be interesting! James