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 A38CAC433F5 for ; Sun, 13 Mar 2022 11:44:22 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S232321AbiCMLp1 (ORCPT ); Sun, 13 Mar 2022 07:45:27 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:55714 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231153AbiCMLpY (ORCPT ); Sun, 13 Mar 2022 07:45:24 -0400 Received: from mail-wm1-f47.google.com (mail-wm1-f47.google.com [209.85.128.47]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id EC2BDB6D31; Sun, 13 Mar 2022 04:44:15 -0700 (PDT) Received: by mail-wm1-f47.google.com with SMTP id n31-20020a05600c3b9f00b003898fc06f1eso10256118wms.1; Sun, 13 Mar 2022 04:44:15 -0700 (PDT) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=x-gm-message-state:message-id:date:mime-version:user-agent:subject :content-language:to:cc:references:from:in-reply-to :content-transfer-encoding; bh=vCaA+Wh+Wx7Ta4aeT/ck2tjXVf6Mb0nC0oCuYVcQ0C8=; b=vbDlQ1Kmpygn0T2K48HSGw2g+liofXV1Kghq9tBgJGHapaUnEgPbxiE4O/ff+C8qKU BH5wey/a3xR32A/8abU13KUhuI7IckToz6upCwf9VDNk0Z05t8995RVsX5b2GOeSV/Xs 4YGSK1XKUaw1wkC39ipRYBYBZwY1T9/95eVV7k9IIqSyyiK802UuVvlh/xEjCFsyIlq3 w9F8BsBtig+9ml7TNMQKnJqasIgZwbhAt0v6q+twCoelWObNwk6SCiOnGldTwD2PU3r2 daA1WuIBwIwznorA8BWx2vlP7Ylg60VLEHxsk3aUGSkcHLNEiXRV6+YduOqClDGMQb/r 3BPA== X-Gm-Message-State: AOAM532jBYz8dlhMmjRiJ6BQWKF6MMilqXyB/sx7I6KBqaMmtJy0Kdkg 5UizjUJu/+j3KnIosDYIUZ1e/Rh3HgQ= X-Google-Smtp-Source: ABdhPJwYFHTtRQ4qBgNnAqWunEUgx1z6UPldJ6h9s9YVPKEFa+nET2P2MzLYmrs6Wg7w4IUb7Zi8EQ== X-Received: by 2002:a05:600c:3506:b0:389:d567:e9fa with SMTP id h6-20020a05600c350600b00389d567e9famr13800144wmq.74.1647171854534; Sun, 13 Mar 2022 04:44:14 -0700 (PDT) Received: from [192.168.64.180] (bzq-219-42-90.isdn.bezeqint.net. [62.219.42.90]) by smtp.gmail.com with ESMTPSA id c124-20020a1c3582000000b00384d42a9638sm12616244wma.2.2022.03.13.04.44.12 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Sun, 13 Mar 2022 04:44:14 -0700 (PDT) Message-ID: <45aed896-ab6a-90f5-9676-e27a7d0128fd@grimberg.me> Date: Sun, 13 Mar 2022 13:44:11 +0200 MIME-Version: 1.0 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:91.0) Gecko/20100101 Thunderbird/91.5.0 Subject: Re: [PATCH v2 3/3] nvmet-tcp: support specifying the congestion-control Content-Language: en-US To: Mingbao Sun , Keith Busch , Jens Axboe , Christoph Hellwig , Chaitanya Kulkarni , linux-nvme@lists.infradead.org, linux-kernel@vger.kernel.org, Eric Dumazet , "David S . Miller" , Hideaki YOSHIFUJI , David Ahern , Jakub Kicinski , netdev@vger.kernel.org Cc: tyler.sun@dell.com, ping.gan@dell.com, yanxiu.cai@dell.com, libin.zhang@dell.com, ao.sun@dell.com References: <20220311103414.8255-1-sunmingbao@tom.com> <20220311103414.8255-3-sunmingbao@tom.com> From: Sagi Grimberg In-Reply-To: <20220311103414.8255-3-sunmingbao@tom.com> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org > From: Mingbao Sun Hey Mingbao, > congestion-control could have a noticeable impaction on the > performance of TCP-based communications. This is of course true > to NVMe_over_TCP. > > Different congestion-controls (e.g., cubic, dctcp) are suitable for > different scenarios. Proper adoption of congestion control would benefit > the performance. On the contrary, the performance could be destroyed. > > Though we can specify the congestion-control of NVMe_over_TCP via > writing '/proc/sys/net/ipv4/tcp_congestion_control', but this also > changes the congestion-control of all the future TCP sockets that > have not been explicitly assigned the congestion-control, thus bringing > potential impaction on their performance. > > So it makes sense to make NVMe_over_TCP support specifying the > congestion-control. And this commit addresses the target side. > > Implementation approach: > the following new file entry was created for user to specify the > congestion-control of each nvmet port. > '/sys/kernel/config/nvmet/ports/X/tcp_congestion' > Then later in nvmet_tcp_add_port, the specified congestion-control > would be applied to the listening socket of the nvmet port. Please see my comments on the host side patch. In addition, specifically on the chosen interface, why should this be port specific? What is the use-case to configure this per-port?