{"id":581,"url":"http://patchwork.ozlabs.org/api/1.0/patches/581/?format=json","project":{"id":7,"url":"http://patchwork.ozlabs.org/api/1.0/projects/7/?format=json","name":"Linux network development","link_name":"netdev","list_id":"netdev.vger.kernel.org","list_email":"netdev@vger.kernel.org","web_url":null,"scm_url":null,"webscm_url":null},"msgid":"<20080919004337.10035.3409.stgit@localhost.localdomain>","date":"2008-09-19T00:43:37","name":"netdev: simple_tx_hash shouldn't hash inside fragments","commit_ref":null,"pull_url":null,"state":"accepted","archived":true,"hash":"bb54a7e351bdc38f286254fe07e8fe71ba0f7077","submitter":{"id":251,"url":"http://patchwork.ozlabs.org/api/1.0/people/251/?format=json","name":"Duyck, Alexander H","email":"alexander.h.duyck@intel.com"},"delegate":{"id":34,"url":"http://patchwork.ozlabs.org/api/1.0/users/34/?format=json","username":"davem","first_name":"David","last_name":"Miller","email":"davem@davemloft.net"},"mbox":"http://patchwork.ozlabs.org/project/netdev/patch/20080919004337.10035.3409.stgit@localhost.localdomain/mbox/","series":[],"check":"pending","checks":"http://patchwork.ozlabs.org/api/patches/581/checks/","tags":{},"headers":{"Return-Path":"","X-Original-To":"patchwork-incoming@ozlabs.org","Delivered-To":"patchwork-incoming@ozlabs.org","Received":["from vger.kernel.org (vger.kernel.org [209.132.176.167])\n\tby ozlabs.org (Postfix) with ESMTP id D5D2FDDEFD\n\tfor ;\n\tFri, 19 Sep 2008 10:43:44 +1000 (EST)","(majordomo@vger.kernel.org) by vger.kernel.org via listexpand\n\tid S1756101AbYISAnk (ORCPT );\n\tThu, 18 Sep 2008 20:43:40 -0400","(majordomo@vger.kernel.org) by vger.kernel.org id S1756063AbYISAnj\n\t(ORCPT ); Thu, 18 Sep 2008 20:43:39 -0400","from mga11.intel.com ([192.55.52.93]:43790 \"EHLO mga11.intel.com\"\n\trhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP\n\tid S1755822AbYISAnj (ORCPT );\n\tThu, 18 Sep 2008 20:43:39 -0400","from fmsmga002.fm.intel.com ([10.253.24.26])\n\tby fmsmga102.fm.intel.com with ESMTP; 18 Sep 2008 17:40:47 -0700","from azsmsx333.amr.corp.intel.com ([10.2.121.77])\n\tby fmsmga002.fm.intel.com with ESMTP; 18 Sep 2008 17:40:37 -0700","from localhost.localdomain ([10.23.35.60]) by\n\tazsmsx333.amr.corp.intel.com with Microsoft\n\tSMTPSVC(6.0.3790.1830); Thu, 18 Sep 2008 17:43:38 -0700","from localhost.localdomain (gitlad [127.0.0.1])\n\tby localhost.localdomain (8.14.2/8.14.2) with ESMTP id m8J0hbNS010065;\n\tThu, 18 Sep 2008 17:43:37 -0700"],"X-ExtLoop1":"1","X-IronPort-AV":"E=Sophos;i=\"4.32,424,1217833200\"; d=\"scan'208\";a=\"381948214\"","From":"Alexander Duyck ","Subject":"[PATCH] netdev: simple_tx_hash shouldn't hash inside fragments","To":"netdev@vger.kernel.org","Cc":"davem@davemloft.net","Date":"Thu, 18 Sep 2008 17:43:37 -0700","Message-ID":"<20080919004337.10035.3409.stgit@localhost.localdomain>","User-Agent":"StGIT/0.14.2","MIME-Version":"1.0","Content-Type":"text/plain; charset=\"utf-8\"","Content-Transfer-Encoding":"7bit","X-OriginalArrivalTime":"19 Sep 2008 00:43:38.0403 (UTC)\n\tFILETIME=[C161D730:01C919F0]","Sender":"netdev-owner@vger.kernel.org","Precedence":"bulk","List-ID":"","X-Mailing-List":"netdev@vger.kernel.org"},"content":"Currently simple_tx_hash is hashing inside of udp fragments. As a result\npackets are getting getting sent to all queues when they shouldn't be.\nThis causes a serious performance regression which can be seen by sending\nUDP frames larger than mtu on multiqueue devices. This change will make\nit so that fragments are hashed only as IP datagrams w/o any protocol\ninformation.\n\nSigned-off-by: Alexander Duyck ","diff":"diff --git a/net/core/dev.c b/net/core/dev.c\nindex 60c51f7..5d9fa1e 100644\n--- a/net/core/dev.c\n+++ b/net/core/dev.c\n@@ -122,6 +122,7 @@\n #include \n #include \n #include \n+#include \n #include \n #include \n #include \n@@ -1667,7 +1668,7 @@ static u16 simple_tx_hash(struct net_device *dev, struct sk_buff *skb)\n {\n \tu32 addr1, addr2, ports;\n \tu32 hash, ihl;\n-\tu8 ip_proto;\n+\tu8 ip_proto = 0;\n \n \tif (unlikely(!simple_tx_hashrnd_initialized)) {\n \t\tget_random_bytes(&simple_tx_hashrnd, 4);\n@@ -1676,7 +1677,8 @@ static u16 simple_tx_hash(struct net_device *dev, struct sk_buff *skb)\n \n \tswitch (skb->protocol) {\n \tcase __constant_htons(ETH_P_IP):\n-\t\tip_proto = ip_hdr(skb)->protocol;\n+\t\tif (!(ip_hdr(skb)->frag_off & htons(IP_MF | IP_OFFSET)))\n+\t\t\tip_proto = ip_hdr(skb)->protocol;\n \t\taddr1 = ip_hdr(skb)->saddr;\n \t\taddr2 = ip_hdr(skb)->daddr;\n \t\tihl = ip_hdr(skb)->ihl;\n","prefixes":[]}