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=-3.8 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED 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 66EABC49ED7 for ; Mon, 16 Sep 2019 14:40:00 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 43AE52067D for ; Mon, 16 Sep 2019 14:40:00 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1730390AbfIPOj7 (ORCPT ); Mon, 16 Sep 2019 10:39:59 -0400 Received: from shards.monkeyblade.net ([23.128.96.9]:47952 "EHLO shards.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726649AbfIPOj7 (ORCPT ); Mon, 16 Sep 2019 10:39:59 -0400 Received: from localhost (80-167-222-154-cable.dk.customer.tdc.net [80.167.222.154]) (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 05F16153CB38A; Mon, 16 Sep 2019 07:39:56 -0700 (PDT) Date: Mon, 16 Sep 2019 16:39:55 +0200 (CEST) Message-Id: <20190916.163955.2206355736506010205.davem@davemloft.net> To: tph@fb.com Cc: netdev@vger.kernel.org, jonathan.lemon@gmail.com, dsj@fb.com, edumazet@google.com, ncardwell@google.com, dave.taht@gmail.com, ycheng@google.com, soheil@google.com Subject: Re: [PATCH v5 2/2] tcp: Add snd_wnd to TCP_INFO From: David Miller In-Reply-To: <20190913232332.44036-2-tph@fb.com> References: <20190913232332.44036-1-tph@fb.com> <20190913232332.44036-2-tph@fb.com> X-Mailer: Mew version 6.8 on Emacs 26.2 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]); Mon, 16 Sep 2019 07:39:59 -0700 (PDT) Sender: netdev-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org From: Thomas Higdon Date: Fri, 13 Sep 2019 23:23:35 +0000 > Neal Cardwell mentioned that snd_wnd would be useful for diagnosing TCP > performance problems -- >> (1) Usually when we're diagnosing TCP performance problems, we do so >> from the sender, since the sender makes most of the >> performance-critical decisions (cwnd, pacing, TSO size, TSQ, etc). >> From the sender-side the thing that would be most useful is to see >> tp->snd_wnd, the receive window that the receiver has advertised to >> the sender. > > This serves the purpose of adding an additional __u32 to avoid the > would-be hole caused by the addition of the tcpi_rcvi_ooopack field. > > Signed-off-by: Thomas Higdon Applied.