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 ws5-mx01.kavi.com (ws5-mx01.kavi.com [34.193.7.191]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id 6B0F1C77B7A for ; Fri, 26 May 2023 08:05:31 +0000 (UTC) Received: from lists.oasis-open.org (oasis.ws5.connectedcommunity.org [10.110.1.242]) by ws5-mx01.kavi.com (Postfix) with ESMTP id 1357F3711B for ; Fri, 26 May 2023 08:05:29 +0000 (UTC) Received: from lists.oasis-open.org (oasis-open.org [10.110.1.242]) by lists.oasis-open.org (Postfix) with ESMTP id 7969C98673A for ; Fri, 26 May 2023 08:05:28 +0000 (UTC) Received: from host09.ws5.connectedcommunity.org (host09.ws5.connectedcommunity.org [10.110.1.97]) by lists.oasis-open.org (Postfix) with QMQP id EA91098662A; Fri, 26 May 2023 08:05:27 +0000 (UTC) Mailing-List: contact virtio-dev-help@lists.oasis-open.org; run by ezmlm List-ID: Sender: Precedence: bulk List-Post: List-Help: List-Unsubscribe: List-Subscribe: Received: from lists.oasis-open.org (oasis-open.org [10.110.1.242]) by lists.oasis-open.org (Postfix) with ESMTP id D9FD09863FC; Fri, 26 May 2023 08:04:26 +0000 (UTC) X-Virus-Scanned: amavisd-new at kavi.com X-Alimail-AntiSpam:AC=PASS;BC=-1|-1;BR=01201311R141e4;CH=green;DM=||false|;DS=||;FP=0|-1|-1|-1|0|-1|-1|-1;HT=ay29a033018046056;MF=hengqi@linux.alibaba.com;NM=1;PH=DS;RN=7;SR=0;TI=SMTPD_---0VjVS-AI_1685088259; Message-ID: <69cd31d4-c059-3edd-f14b-bdf03ac4b200@linux.alibaba.com> Date: Fri, 26 May 2023 16:04:18 +0800 MIME-Version: 1.0 User-Agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10.15; rv:102.0) Gecko/20100101 Thunderbird/102.10.0 From: Heng Qi To: "Michael S. Tsirkin" Cc: virtio-dev@lists.oasis-open.org, virtio-comment@lists.oasis-open.org, Parav Pandit , Jason Wang , Yuri Benditovich , Xuan Zhuo References: <20230522050236.49433-1-hengqi@linux.alibaba.com> <20230522151522-mutt-send-email-mst@kernel.org> <20230523035803.GB23504@h68b04307.sqa.eu95> In-Reply-To: <20230523035803.GB23504@h68b04307.sqa.eu95> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 8bit Subject: Re: [virtio-dev] Re: [virtio-comment] Re: [PATCH v14] virtio-net: support inner header hash 在 2023/5/23 上午11:58, Heng Qi 写道: > On Mon, May 22, 2023 at 03:19:16PM -0400, Michael S. Tsirkin wrote: >> On Mon, May 22, 2023 at 01:02:36PM +0800, Heng Qi wrote: >>> 1. Currently, a received encapsulated packet has an outer and an inner header, but >>> the virtio device is unable to calculate the hash for the inner header. The same >>> flow can traverse through different tunnels, resulting in the encapsulated >>> packets being spread across multiple receive queues (refer to the figure below). >>> However, in certain scenarios, we may need to direct these encapsulated packets of >>> the same flow to a single receive queue. This facilitates the processing >>> of the flow by the same CPU to improve performance (warm caches, less locking, etc.). >>> >>> client1 client2 >>> | +-------+ | >>> +------->|tunnels|<--------+ >>> +-------+ >>> | | >>> v v >>> +-----------------+ >>> | monitoring host | >>> +-----------------+ >>> >>> To achieve this, the device can calculate a symmetric hash based on the inner headers >>> of the same flow. >>> >>> 2. For legacy systems, they may lack entropy fields which modern protocols have in >>> the outer header, resulting in multiple flows with the same outer header but >>> different inner headers being directed to the same receive queue. This results in >>> poor receive performance. >>> >>> To address this limitation, inner header hash can be used to enable the device to advertise >>> the capability to calculate the hash for the inner packet, regaining better receive performance. >>> >>> Signed-off-by: Heng Qi >>> Reviewed-by: Xuan Zhuo >>> --- >>> v13->v14: >>> 1. Move supported_hash_tunnel_types from config space into cvq command. @Parav Pandit >>> 2. Rebase to master branch. >>> 3. Some minor modifications. >> So, I proposed adding a "generic UDP tunnel" option which simply uses UDP source >> port for hash. I think it will help us not having to chaise future tunnels as >> more and more are added. > I agree, but I thought we'd do this in another thread, sorry. > Following your suggestion, we should add a field similar to > \field{generic_udp_tunnel_option} in the virtnet_hash_tunnel_config_set > structure. > > \field{generic_udp_tunnel_option} should be 0, 1 or 2. > > \field{hash_tunnel_types} is still useful, but for more general purpose we need > to use it together with \field{generic_udp_tunnel_option}. > > When \field{generic_udp_tunnel_option} is 0, all tunneling protocols included in > \field{hash_tunnel_types} use the inner header for hashing. For other tunnel > protocols not included in \field{hash_tunnel_types}, the hash is calculated as if > VIRTIO_NET_F_TUNNEL_HASH is not negotiated. > > When \field{generic_udp_tunnel_option} is 1, all tunneling protocols included in > \field{hash_tunnel_types} use the inner header for hashing. For other tunnel > protocols not included in \field{hash_tunnel_types}, if their outer headers are > based on UDP protocol, the device use the outer UDP source port for hashing. > For the rest of the tunnel protocols, the hash is calculated as if VIRTIO_NET_F_TUNNEL_HASH > was not negotiated. > > When \field{generic_udp_tunnel_option} is 2, for all UDP tunneling protocols, > the outer udp source port is used for hashing, otherwise if the tunneling protocol > is included in \field{hash_tunnel_types}, the inner header is used for hashing. > For the rest of the tunnel protocols, the hash is calculated as if VIRTIO_NET_F_TUNNEL_HASH > was not negotiated. > > And for this option, we need to add a reminder: > Although the \field{generic_udp_tunnel_option} helps us adapt to more new > tunneling protocols, it is still an unreliable option, especially for > tunneling protocols that use "SHOULD" "Recommended" in their own > specifications, because it means the udp source port does not > always fully identify a stream. > Hi, Michael. Do you agree with this plan? Please let me know if you have any comments.:) If there are no comments, I can start a new version to make progress. Thanks. >> I also suggested dropping some tunnels which are less common and where >> the specification is unambiguous enough that source port should include >> inner hash. > OK, I'll re-screen and update the tunneling protocols we already include > (e.g. remove STT since it fits what you said). > > Thanks. > > --------------------------------------------------------------------- > To unsubscribe, e-mail: virtio-dev-unsubscribe@lists.oasis-open.org > For additional commands, e-mail: virtio-dev-help@lists.oasis-open.org --------------------------------------------------------------------- To unsubscribe, e-mail: virtio-dev-unsubscribe@lists.oasis-open.org For additional commands, e-mail: virtio-dev-help@lists.oasis-open.org