From mboxrd@z Thu Jan 1 00:00:00 1970 From: David Miller Subject: Re: Performance regression on kernels 3.10 and newer Date: Thu, 14 Aug 2014 16:20:24 -0700 (PDT) Message-ID: <20140814.162024.2218312002979492106.davem@davemloft.net> References: <53ECFDAB.5010701@intel.com> <1408041962.6804.31.camel@edumazet-glaptop2.roam.corp.google.com> <53ED4354.9090904@intel.com> Mime-Version: 1.0 Content-Type: Text/Plain; charset=us-ascii Content-Transfer-Encoding: 7bit Cc: eric.dumazet@gmail.com, netdev@vger.kernel.org To: alexander.h.duyck@intel.com Return-path: Received: from shards.monkeyblade.net ([149.20.54.216]:33754 "EHLO shards.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932078AbaHNXUZ (ORCPT ); Thu, 14 Aug 2014 19:20:25 -0400 In-Reply-To: <53ED4354.9090904@intel.com> Sender: netdev-owner@vger.kernel.org List-ID: From: Alexander Duyck Date: Thu, 14 Aug 2014 16:16:36 -0700 > Are you sure about each socket having it's own DST? Everything I see > seems to indicate it is somehow associated with IP. Right it should be, unless you have exception entries created by path MTU or redirects. WRT prequeue, it does the right thing for dumb apps that block in receive. But because it causes the packet to cross domains as it does, we can't do a lot of tricks which we normally can do, and that's why the refcounting on the dst is there now. Perhaps we can find a clever way to elide that refcount, who knows.