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=-13.3 required=3.0 tests=BAYES_00,DKIMWL_WL_MED, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,USER_IN_DEF_DKIM_WL 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 98908C3526F for ; Mon, 7 Dec 2020 16:35:01 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 74E13238E7 for ; Mon, 7 Dec 2020 16:35:01 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727855AbgLGQeu (ORCPT ); Mon, 7 Dec 2020 11:34:50 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:59668 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726137AbgLGQes (ORCPT ); Mon, 7 Dec 2020 11:34:48 -0500 Received: from mail-vs1-xe41.google.com (mail-vs1-xe41.google.com [IPv6:2607:f8b0:4864:20::e41]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id E609EC061793 for ; Mon, 7 Dec 2020 08:34:02 -0800 (PST) Received: by mail-vs1-xe41.google.com with SMTP id w18so7870938vsk.12 for ; Mon, 07 Dec 2020 08:34:02 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20161025; h=mime-version:references:in-reply-to:from:date:message-id:subject:to :cc:content-transfer-encoding; bh=o/DtfijALD2g5Nx6U5RyBf5K19aIZpTx6Lezd9276b0=; b=L2LXbdf4t7st2CFnH8cc90+6ihSe/uHXFKUaoqxOW3IWgjiYpQqpgoVRpj/4LGlLnC xruVNubc31f1rwlfX/0NMX88upIuvgRNgI17Kg1zkMUSidoKpTQ6luc5cTJ15K2qLIDr PdATwyU2lrX86Yjrwvq4kCl2QvVX8wIKmEoGMir35m4LPM6+pT1JU7bwrF3A6pJVF7vL xa7MhNj0qJnUZGWr9eeCg3qogLS/jE5y4oeYx2AmdqxpAIPM46DM9p4pDGgfEsuBn8hP QRWax5vBJGAt7hSeGJNo+egSoINvAWUbdy0megzN+Czk3DYqURDcA0uJCB7dhjY6M1uW OxIQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:mime-version:references:in-reply-to:from:date :message-id:subject:to:cc:content-transfer-encoding; bh=o/DtfijALD2g5Nx6U5RyBf5K19aIZpTx6Lezd9276b0=; b=RKlyqZohLyxjQqMDZJ5jN0GtH+CSkNeBrt/HZmMZB8CouxpPBFtayIJ1YjD18T9/e6 kMQl1BQaeWpNaNvl3GWvpKGKK/Pme5CkJCH9lX++/WlxTVq8brAW2rexkGuX1phRMdeF uYu2FQmiFFmD0Z/d5/0O+hHW5C7KFGhFFEONI5nhdil78BleJoYxJE5qMHfufJSidMfC 3rWdc7WFbSMNWG9iAa5jVG5xWdliUqZetWt9T4aWCmP10c+1osfzqmIcilryhCgIRwn1 pfjfS0DvcvUp7uY/nqQAgvnomrwOMOMpdhEFPe8C1mxGWSSChDHtuW7gv915G+rTJqM4 M7MA== X-Gm-Message-State: AOAM532SL1WOQBZG9fsqLDvinX8qLN4+rih657148rigEqhEXWSoTgtQ E4dUn9JS381qKIASCA1W0z6ncbqdBi8w5MAEJfdhxA== X-Google-Smtp-Source: ABdhPJxV4rbu4d9mkLKYYi6mlLJKyHzo94VKtoDQuaCMVPtQ9zLfd9WZXhsn2ZapvXnVIfpuzrxqAikn7Uach7EyNy0= X-Received: by 2002:a67:cd9a:: with SMTP id r26mr12848920vsl.52.1607358841676; Mon, 07 Dec 2020 08:34:01 -0800 (PST) MIME-Version: 1.0 References: <20201204180622.14285-1-abuehaze@amazon.com> <44E3AA29-F033-4B8E-A1BC-E38824B5B1E3@amazon.com> <3F02FF08-EDA6-4DFD-8D93-479A5B05E25A@amazon.com> <781BA871-5D3D-4C89-9629-81345CC41C5C@amazon.com> In-Reply-To: From: Neal Cardwell Date: Mon, 7 Dec 2020 11:33:44 -0500 Message-ID: Subject: Re: [PATCH net-next] tcp: optimise receiver buffer autotuning initialisation for high latency connections To: Eric Dumazet Cc: "Mohamed Abuelfotoh, Hazem" , "netdev@vger.kernel.org" , "stable@vger.kernel.org" , "ycheng@google.com" , "weiwan@google.com" , "Strohman, Andy" , "Herrenschmidt, Benjamin" Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org On Mon, Dec 7, 2020 at 11:23 AM Eric Dumazet wrote: > > On Mon, Dec 7, 2020 at 5:09 PM Mohamed Abuelfotoh, Hazem > wrote: > > > > >Since I can not reproduce this problem with another NIC on x86, I > > >really wonder if this is not an issue with ENA driver on PowerPC > > >perhaps ? > > > > > > I am able to reproduce it on x86 based EC2 instances using ENA or Xen= netfront or Intel ixgbevf driver on the receiver so it's not specific to E= NA, we were able to easily reproduce it between 2 VMs running in virtual bo= x on the same physical host considering the environment requirements I ment= ioned in my first e-mail. > > > > What's the RTT between the sender & receiver in your reproduction? Are = you using bbr on the sender side? > > > 100ms RTT > > Which exact version of linux kernel are you using ? Thanks for testing this, Eric. Would you be able to share the MTU config commands you used, and the tcpdump traces you get? I'm surprised that receive buffer autotuning would work for advmss of around 6500 or higher. thanks, neal