From mboxrd@z Thu Jan 1 00:00:00 1970 From: Eric Dumazet Subject: Re: One question about __tcp_select_window() Date: Tue, 17 Apr 2018 07:43:48 -0700 Message-ID: <6b7c1a82-e253-09bd-fd3e-363ce6a84653@gmail.com> References: Mime-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: 7bit To: Wang Jian , netdev@vger.kernel.org Return-path: Received: from mail-pl0-f47.google.com ([209.85.160.47]:39097 "EHLO mail-pl0-f47.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751345AbeDQOnx (ORCPT ); Tue, 17 Apr 2018 10:43:53 -0400 Received: by mail-pl0-f47.google.com with SMTP id e7-v6so12109122plt.6 for ; Tue, 17 Apr 2018 07:43:53 -0700 (PDT) In-Reply-To: Content-Language: en-US Sender: netdev-owner@vger.kernel.org List-ID: On 04/17/2018 06:53 AM, Wang Jian wrote: > I test the fix with 4.17.0-rc1+ and it seems work. > > 1. iperf -c IP -i 20 -t 60 -w 1K > with-fix vs without-fix : 1.15Gbits/sec vs 1.05Gbits/sec > I also try other windows and have similar results. > > 2. Use tcp probe trace snd_wind. > with-fix vs without-fix: 1245568 vs 1042816 > > 3. I don't see extra retransmit/drops. > Unfortunately I have no idea what exact problem you had to solve. Setting small windows is not exactly the path we are taking. And I do not know how many side effects your change will have for 'standard' flows using autotuning or sane windows.