From mboxrd@z Thu Jan 1 00:00:00 1970 From: David Miller Subject: Re: [net-next v2 1/1] tipc: improve link resiliency when rps is activated Date: Sat, 11 Nov 2017 15:36:33 +0900 (KST) Message-ID: <20171111.153633.2266031879610202255.davem@davemloft.net> References: <1510131566-30308-1-git-send-email-jon.maloy@ericsson.com> Mime-Version: 1.0 Content-Type: Text/Plain; charset=us-ascii Content-Transfer-Encoding: 7bit Cc: netdev@vger.kernel.org, mohan.krishna.ghanta.krishnamurthy@ericsson.com, tung.q.nguyen@dektech.com.au, hoang.h.le@dektech.com.au, canh.d.luu@dektech.com.au, ying.xue@windriver.com, tipc-discussion@lists.sourceforge.net To: jon.maloy@ericsson.com Return-path: Received: from shards.monkeyblade.net ([184.105.139.130]:44090 "EHLO shards.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751267AbdKKGgh (ORCPT ); Sat, 11 Nov 2017 01:36:37 -0500 In-Reply-To: <1510131566-30308-1-git-send-email-jon.maloy@ericsson.com> Sender: netdev-owner@vger.kernel.org List-ID: From: Jon Maloy Date: Wed, 8 Nov 2017 09:59:26 +0100 > Currently, the TIPC RPS dissector is based only on the incoming packets' > source node address, hence steering all traffic from a node to the same > core. We have seen that this makes the links vulnerable to starvation > and unnecessary resets when we turn down the link tolerance to very low > values. > > To reduce the risk of this happening, we exempt probe and probe replies > packets from the convergence to one core per source node. Instead, we do > the opposite, - we try to diverge those packets across as many cores as > possible, by randomizing the flow selector key. > > To make such packets identifiable to the dissector, we add a new > 'is_keepalive' bit to word 0 of the LINK_PROTOCOL header. This bit is > set both for PROBE and PROBE_REPLY messages, and only for those. > > It should be noted that these packets are not part of any flow anyway, > and only constitute a minuscule fraction of all packets sent across a > link. Hence, there is no risk that this will affect overall performance. > > Acked-by: Ying Xue > Signed-off-by: Jon Maloy Applied, thanks.