From mboxrd@z Thu Jan 1 00:00:00 1970 From: David Miller Subject: Re: [PATCH net-next 0/6] tcp: sender chronographs instrumentation Date: Mon, 28 Nov 2016 16:19:06 -0500 (EST) Message-ID: <20161128.161906.1900426045355871354.davem@davemloft.net> References: <1480191016-73210-1-git-send-email-ycheng@google.com> Mime-Version: 1.0 Content-Type: Text/Plain; charset=us-ascii Content-Transfer-Encoding: 7bit Cc: soheil@google.com, francisyyan@gmail.com, netdev@vger.kernel.org, ncardwell@google.com, edumazet@google.com To: ycheng@google.com Return-path: Received: from shards.monkeyblade.net ([184.105.139.130]:42538 "EHLO shards.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753105AbcK1VTI (ORCPT ); Mon, 28 Nov 2016 16:19:08 -0500 In-Reply-To: <1480191016-73210-1-git-send-email-ycheng@google.com> Sender: netdev-owner@vger.kernel.org List-ID: From: Yuchung Cheng Date: Sat, 26 Nov 2016 12:10:10 -0800 > This patch set provides instrumentation on TCP sender limitations. > While developing the BBR congestion control, we noticed that TCP > sending process is often limited by factors unrelated to congestion > control: insufficient sender buffer and/or insufficient receive > window/buffer to saturate the network bandwidth. Unfortunately these > limits are not visible to the users and often the poor performance > is attributed to the congestion control of choice. > > Thie patch aims to help users get the high level understanding of > where sending process is limited by, similar to the TCP_INFO design. > It is not to replace detailed kernel tracing and instrumentation > facilities. > > In addition this patch set provides a new option to the timestamping > work to instrument these limits on application data unit. For exampe, > one can use SO_TIMESTAMPING and this patch set to measure the how > long a particular HTTP response is limited by small receive window. > > Patch set was initially written by Francis Yan then polished > by Yuchung Cheng, with lots of help from Eric Dumazet and Soheil > Hassas Yeganeh. Looks great, series applied, thanks!