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 Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 940B4CDB465 for ; Mon, 16 Oct 2023 09:11:01 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S232330AbjJPJLA (ORCPT ); Mon, 16 Oct 2023 05:11:00 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:49530 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S232912AbjJPJKz (ORCPT ); Mon, 16 Oct 2023 05:10:55 -0400 Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 1A331E5 for ; Mon, 16 Oct 2023 02:10:54 -0700 (PDT) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 49F4FC433C7; Mon, 16 Oct 2023 09:10:50 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1697447453; bh=9Lx78ecl0MZuF5F5PNauQCDBeFdcUns/BLrcQKTwtW4=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=UKpgoN/b8/gx5spIIHKQLj/BYMaITLA0ShZI8w54Z6AZp3+yxr+251NrFO3tI9/HA dKuuuaYuLdJRYP4053aXJObFgODZ8XabcwBbEU7z1bl3ojOSeSyAr2+h/jSiOtNRvv x0+44lYRpiiNjJ/Pr/xd80TumRQQ0bWoaXWJE4Wz7a3QKh/SwR7NlIUN8qDhptlsWQ ItL7ryT709B5NYfrKHbsSdf79BPk+Ioj7jZrYg4C2GOamcEbXeK66myoQtT6o7Rtc4 hV9OmkzeywmN8uujBf5iHby+/H6F6OgKHk62t8aRudGlfHwkRZ4dOOzkpMHKmq3oPU 3kZxk5sEhKImw== Date: Mon, 16 Oct 2023 11:10:48 +0200 From: Simon Horman To: Haiyang Zhang Cc: linux-hyperv@vger.kernel.org, netdev@vger.kernel.org, kys@microsoft.com, davem@davemloft.net, edumazet@google.com, kuba@kernel.org, pabeni@redhat.com, corbet@lwn.net, dsahern@kernel.org, ncardwell@google.com, ycheng@google.com, kuniyu@amazon.com, morleyd@google.com, mfreemon@cloudflare.com, mubashirq@google.com, linux-doc@vger.kernel.org, weiwan@google.com, linux-kernel@vger.kernel.org Subject: Re: [PATCH net-next,v3] tcp: Set pingpong threshold via sysctl Message-ID: <20231016091048.GG1501712@kernel.org> References: <1697056244-21888-1-git-send-email-haiyangz@microsoft.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1697056244-21888-1-git-send-email-haiyangz@microsoft.com> Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Wed, Oct 11, 2023 at 01:30:44PM -0700, Haiyang Zhang wrote: > TCP pingpong threshold is 1 by default. But some applications, like SQL DB > may prefer a higher pingpong threshold to activate delayed acks in quick > ack mode for better performance. > > The pingpong threshold and related code were changed to 3 in the year > 2019 in: > commit 4a41f453bedf ("tcp: change pingpong threshold to 3") > And reverted to 1 in the year 2022 in: > commit 4d8f24eeedc5 ("Revert "tcp: change pingpong threshold to 3"") > > There is no single value that fits all applications. > Add net.ipv4.tcp_pingpong_thresh sysctl tunable, so it can be tuned for > optimal performance based on the application needs. > > Signed-off-by: Haiyang Zhang > --- > v3: Updated doc as suggested by Neal Cardwell. > Updated variable location in struct netns_ipv4 as suggested by Kuniyuki > Iwashima. > > v2: Make it per-namesapce setting, and other updates suggested by Neal Cardwell, > and Kuniyuki Iwashima. Thanks, this looks clean to me. It seems to address the review of v2. And keeps the knob as syctl as discussed in v2. Reviewed-by: Simon Horman