[{"id":1760396,"web_url":"http://patchwork.ozlabs.org/comment/1760396/","msgid":"<20170830.112051.1883418035935384084.davem@davemloft.net>","list_archive_url":null,"date":"2017-08-30T18:20:51","subject":"Re: [PATCH net-next 0/2] tcp: re-add header prediction","submitter":{"id":15,"url":"http://patchwork.ozlabs.org/api/people/15/","name":"David Miller","email":"davem@davemloft.net"},"content":"From: Florian Westphal \nDate: Wed, 30 Aug 2017 19:24:56 +0200\n\n> Eric reported a performance regression caused by header prediction\n> removal.\n> \n> We now call tcp_ack() much more frequently, for some workloads\n> this brings in enough cache line misses to become noticeable.\n> \n> We could possibly still kill HP provided we find a different\n> way to suppress unneeded tcp_ack, but given we're late in\n> the cycle it seems preferable to revert.\n\nIndeed, reverting at this point in the game is the best thing\nto do right now.\n\nApplied, thanks.","headers":{"Return-Path":"","X-Original-To":"patchwork-incoming@ozlabs.org","Delivered-To":"patchwork-incoming@ozlabs.org","Authentication-Results":"ozlabs.org;\n\tspf=none (mailfrom) smtp.mailfrom=vger.kernel.org\n\t(client-ip=209.132.180.67; helo=vger.kernel.org;\n\tenvelope-from=netdev-owner@vger.kernel.org;\n\treceiver=)","Received":["from vger.kernel.org (vger.kernel.org [209.132.180.67])\n\tby ozlabs.org (Postfix) with ESMTP id 3xjDMw30y0z9s7M\n\tfor ;\n\tThu, 31 Aug 2017 04:21:00 +1000 (AEST)","(majordomo@vger.kernel.org) by vger.kernel.org via listexpand\n\tid S1752717AbdH3SU5 (ORCPT );\n\tWed, 30 Aug 2017 14:20:57 -0400","from shards.monkeyblade.net ([184.105.139.130]:58630 \"EHLO\n\tshards.monkeyblade.net\" rhost-flags-OK-OK-OK-OK) by vger.kernel.org\n\twith ESMTP id S1752090AbdH3SUx (ORCPT\n\t); Wed, 30 Aug 2017 14:20:53 -0400","from localhost (74-93-104-98-Washington.hfc.comcastbusiness.net\n\t[74.93.104.98]) (using TLSv1 with cipher AES256-SHA (256/256 bits))\n\t(Client did not present a certificate)\n\t(Authenticated sender: davem-davemloft)\n\tby shards.monkeyblade.net (Postfix) with ESMTPSA id 28C74134190AF;\n\tWed, 30 Aug 2017 11:20:52 -0700 (PDT)"],"Date":"Wed, 30 Aug 2017 11:20:51 -0700 (PDT)","Message-Id":"<20170830.112051.1883418035935384084.davem@davemloft.net>","To":"fw@strlen.de","Cc":"netdev@vger.kernel.org, edumazet@google.com","Subject":"Re: [PATCH net-next 0/2] tcp: re-add header prediction","From":"David Miller ","In-Reply-To":"<20170830172458.18544-1-fw@strlen.de>","References":"<20170830172458.18544-1-fw@strlen.de>","X-Mailer":"Mew version 6.7 on Emacs 25.2 / Mule 6.0 (HANACHIRUSATO)","Mime-Version":"1.0","Content-Type":"Text/Plain; charset=us-ascii","Content-Transfer-Encoding":"7bit","X-Greylist":"Sender succeeded SMTP AUTH, not delayed by\n\tmilter-greylist-4.5.12 (shards.monkeyblade.net\n\t[149.20.54.216]); Wed, 30 Aug 2017 11:20:52 -0700 (PDT)","Sender":"netdev-owner@vger.kernel.org","Precedence":"bulk","List-ID":"","X-Mailing-List":"netdev@vger.kernel.org"}}]