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=-11.0 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,INCLUDES_CR_TRAILER,MAILING_LIST_MULTI, SPF_HELO_NONE,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 EE812C19437 for ; Mon, 7 Dec 2020 18:54:43 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id B5A24238E3 for ; Mon, 7 Dec 2020 18:54:43 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1725915AbgLGSy1 (ORCPT ); Mon, 7 Dec 2020 13:54:27 -0500 Received: from mail.kernel.org ([198.145.29.99]:41978 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725877AbgLGSy1 (ORCPT ); Mon, 7 Dec 2020 13:54:27 -0500 Date: Mon, 7 Dec 2020 10:53:45 -0800 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1607367227; bh=50Fbpy3MX6B8trLlZELaraTyt75dPDYAPrm+Bv+kS68=; h=From:To:Cc:Subject:In-Reply-To:References:From; b=amTGpTydm7QXBa9jITflWxd2+dZ0EfIdAUYMKy7Gkb4tt5VJQDYrjJHLI3uPWnPKc RJWNRDGyaWkETYu84jN0Sv7ZT59nrgyFQ4f4s3x49JbG8lzxVchDyvZW7H2KH2+7sO jM2CiZmK78bmiq59G4iokXDOnmz2+6WdrzTuNU/5d5jSLvlqbZqWHlPX2KZH7fS99d wygCa8Yym49Jp2OYfkxm1OJo3O5+BpOkll26MTHRzcwqkhgfN1CqsHa7inwGWdHVkD s8Zb18Av0oQzPzkNuocbbAWT03/+5HHYBX/euwhzU0LcdXp6Fneew0YKUOI1zMzesF pDkgOSBV5Gbyg== From: Jakub Kicinski To: Hazem Mohamed Abuelfotoh Cc: , , , , , , , Subject: Re: [PATCH net] tcp: fix receive buffer autotuning to trigger for any valid advertised MSS Message-ID: <20201207105345.4a4474f3@kicinski-fedora-pc1c0hjn.DHCP.thefacebook.com> In-Reply-To: <20201207114625.9079-1-abuehaze@amazon.com> References: <20201207114625.9079-1-abuehaze@amazon.com> MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org On Mon, 7 Dec 2020 11:46:25 +0000 Hazem Mohamed Abuelfotoh wrote: > Previously receiver buffer auto-tuning starts after receiving > one advertised window amount of data.After the initial > receiver buffer was raised by > commit a337531b942b ("tcp: up initial rmem to 128KB > and SYN rwin to around 64KB"),the receiver buffer may > take too long for TCP autotuning to start raising > the receiver buffer size. > commit 041a14d26715 ("tcp: start receiver buffer autotuning sooner") > tried to decrease the threshold at which TCP auto-tuning starts > but it's doesn't work well in some environments > where the receiver has large MTU (9001) especially with high RTT > connections as in these environments rcvq_space.space will be the same > as rcv_wnd so TCP autotuning will never start because > sender can't send more than rcv_wnd size in one round trip. > To address this issue this patch is decreasing the initial > rcvq_space.space so TCP autotuning kicks in whenever the sender is > able to send more than 5360 bytes in one round trip regardless the > receiver's configured MTU. > > Fixes: a337531b942b ("tcp: up initial rmem to 128KB and SYN rwin to around 64KB") > Fixes: 041a14d26715 ("tcp: start receiver buffer autotuning sooner") > > Signed-off-by: Hazem Mohamed Abuelfotoh If the discussion concludes in favor of this patch please un-indent this commit message, remove the empty line after the fixes tag, and repost.