From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-5.3 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS, USER_AGENT_SANE_1 autolearn=no autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 0D72DC433E0 for ; Thu, 7 Jan 2021 17:46:27 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id CBE9A2076E for ; Thu, 7 Jan 2021 17:46:26 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1729023AbhAGRq0 (ORCPT ); Thu, 7 Jan 2021 12:46:26 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:58822 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728843AbhAGRqZ (ORCPT ); Thu, 7 Jan 2021 12:46:25 -0500 Received: from Chamillionaire.breakpoint.cc (Chamillionaire.breakpoint.cc [IPv6:2a0a:51c0:0:12e:520::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 65490C0612F5 for ; Thu, 7 Jan 2021 09:45:45 -0800 (PST) Received: from fw by Chamillionaire.breakpoint.cc with local (Exim 4.92) (envelope-from ) id 1kxZLu-00049G-Hx; Thu, 07 Jan 2021 18:45:38 +0100 Date: Thu, 7 Jan 2021 18:45:38 +0100 From: Florian Westphal To: Jakub Kicinski Cc: lll , Eric Dumazet , netdev@vger.kernel.org, davem@davemloft.net, fw@strlen.de, soheil@google.com, ncardwell@google.com, ycheng@google.com Subject: Re: [PATCH] tcp: remove obsolete paramter sysctl_tcp_low_latency Message-ID: <20210107174538.GA19605@breakpoint.cc> References: <1608271876-120934-1-git-send-email-liyonglong@chinatelecom.cn> <20201218164647.1bcc6cb9@kicinski-fedora-pc1c0hjn.dhcp.thefacebook.com> <20210107090635.440b1fc6@kicinski-fedora-pc1c0hjn.dhcp.thefacebook.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20210107090635.440b1fc6@kicinski-fedora-pc1c0hjn.dhcp.thefacebook.com> User-Agent: Mutt/1.10.1 (2018-07-13) Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org Jakub Kicinski wrote: > > Got it. But a question: why tcp_tw_recycle can be removed totally? > > it is also part of uAPI > > Good question, perhaps with tcp_tw_recycle we wanted to make sure users > who depended on it notice removal, since the feature was broken by > design? > > tcp_low_latency is an optimization, not functionality which users may > depend on. > > But I may be wrong so CCing authors. I guess it was just a case of 'noone noticed'. I'm not sure if anyone would notice dropping lowlatency sysctl, was just a case of 'overly careful'. Personally I'd rather have them gone so 'sysctl tcp.bla' shows if the feature exists/does something.