From mboxrd@z Thu Jan 1 00:00:00 1970 From: David Miller Subject: Re: [PATCH] ipv4: Cache local output routes Date: Tue, 14 Aug 2012 14:47:29 -0700 (PDT) Message-ID: <20120814.144729.2212634746787730897.davem@davemloft.net> References: <50289A37.6000209@intel.com> Mime-Version: 1.0 Content-Type: Text/Plain; charset=us-ascii Content-Transfer-Encoding: 7bit Cc: netdev@vger.kernel.org, alex.shi@intel.com To: zheng.z.yan@intel.com Return-path: Received: from shards.monkeyblade.net ([149.20.54.216]:38489 "EHLO shards.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751004Ab2HNVr3 (ORCPT ); Tue, 14 Aug 2012 17:47:29 -0400 In-Reply-To: <50289A37.6000209@intel.com> Sender: netdev-owner@vger.kernel.org List-ID: From: "Yan, Zheng" Date: Mon, 13 Aug 2012 14:09:59 +0800 > Commit caacf05e5ad1abf causes big drop of UDP loop back performance. > The cause of the regression is that we do not cache the local output > routes. Each time we send a datagram from unconnected UDP socket, > the kernel allocates a dst_entry and adds it to the rt_uncached_list. > It creates lock contention on the rt_uncached_lock. > > Reported-by: Alex Shi > Signed-off-by: Yan, Zheng I was pretty sure not using 'fi' was necessary for semantic reasons here, but I can't find any such requirement, so I've applied this, thanks.