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=-0.9 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_PASS autolearn=ham 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 4166EC43387 for ; Sat, 15 Dec 2018 19:27:54 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 12D292084D for ; Sat, 15 Dec 2018 19:27:53 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728877AbeLOT1w (ORCPT ); Sat, 15 Dec 2018 14:27:52 -0500 Received: from shards.monkeyblade.net ([23.128.96.9]:53876 "EHLO shards.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726641AbeLOT1w (ORCPT ); Sat, 15 Dec 2018 14:27:52 -0500 Received: from localhost (unknown [IPv6:2601:601:9f80:35cd::cf9]) (using TLSv1 with cipher AES256-SHA (256/256 bits)) (Client did not present a certificate) (Authenticated sender: davem-davemloft) by shards.monkeyblade.net (Postfix) with ESMTPSA id D2CFB14E89C57; Sat, 15 Dec 2018 11:27:51 -0800 (PST) Date: Sat, 15 Dec 2018 11:27:51 -0800 (PST) Message-Id: <20181215.112751.741520579999284155.davem@davemloft.net> To: eric.dumazet@gmail.com Cc: laoar.shao@gmail.com, edumazet@google.com, netdev@vger.kernel.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH net-next] tcp: minor optimization for calculating packets_out in tcp connect From: David Miller In-Reply-To: <48971720-96e1-a48f-a1f5-3a96aa3fae7a@gmail.com> References: <1544866389-11168-1-git-send-email-laoar.shao@gmail.com> <48971720-96e1-a48f-a1f5-3a96aa3fae7a@gmail.com> X-Mailer: Mew version 6.8 on Emacs 26.1 Mime-Version: 1.0 Content-Type: Text/Plain; charset=us-ascii Content-Transfer-Encoding: 7bit X-Greylist: Sender succeeded SMTP AUTH, not delayed by milter-greylist-4.5.12 (shards.monkeyblade.net [149.20.54.216]); Sat, 15 Dec 2018 11:27:52 -0800 (PST) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Eric Dumazet Date: Sat, 15 Dec 2018 04:59:00 -0800 > > > On 12/15/2018 01:33 AM, Yafang Shao wrote: >> When we building a syn packet, the tcp_skb_pcount(skb) is always 1, >> which is set in tcp_init_nondata_skb(). >> Regarding the syn_data, it is set through >> memcpy(syn_data->cb, syn->cb, sizeof(syn->cb)), >> which is always 1 as well. >> >> So we don't need to use tcp_skb_pcount(skb), that could give us a >> little improvement. >> > > I dunno, I find current code more self-documented. > > This is not fast path, so I would suggest we keep it. I agree, I won't be applying this.