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 9A15EC77B7A for ; Thu, 1 Jun 2023 11:06:38 +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 3F8BE42571 for ; Thu, 1 Jun 2023 11:06:36 +0000 (UTC) Received: from lists.oasis-open.org (oasis-open.org [10.110.1.242]) by lists.oasis-open.org (Postfix) with ESMTP id 24EAB9867AB for ; Thu, 1 Jun 2023 11:06:35 +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 16BF1983DE3; Thu, 1 Jun 2023 11:06:35 +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 06902986605 for ; Thu, 1 Jun 2023 11:06:35 +0000 (UTC) X-Virus-Scanned: amavisd-new at kavi.com X-MC-Unique: kH6wwNfXO8WCbxwVWJis_g-1 X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20221208; t=1685617589; x=1688209589; h=in-reply-to:content-transfer-encoding:content-disposition :mime-version:references:message-id:subject:cc:to:from:date :x-gm-message-state:from:to:cc:subject:date:message-id:reply-to; bh=VHgcheh1VtOyKcsW5H4/x/YR1+Tw2ukhdRKbcD+C/hY=; b=XYfAT/eRxMUloNlXLsPkuQw/uRVWEZamTgIXkMXv5VbLq8E/A2TOI80sGoMLQIjaOe xREvj5WYZ49sORdZOYQx1KDj9U/I0HBVJNBzqgcgLmLa8lsKmm6mxCnpw7yywA/nXhmJ VctEjIW2tSG7AodCJ/52xaebynjUr9QdS+RZUmC6IEC/unpVnKn//1bvA69GHR/5GkS5 u+cC1bdBw/GJwxkmGnve6SAgngSJEvzrPzW6DGZQK2f4odrtO/X8WtcMDoJIBboL2JAG ZXpoN5BnFpBzecCP+diBfHR4J8Zq0SDNOOKIvZMPYHKtIZ9llw0wrk42S83sTYa0SP54 gV1g== X-Gm-Message-State: AC+VfDyreZ74JZG+79j6N9Jsh1ohEMxjUPAXBMVXtLg+Pny0Rh75h4l9 s77xP7rRQ3pheAj70gFWJ4Z9WdVn0PiJ6nah7S/uP9hJZn3QEnJDr+75MN6L8Lw4GJ85BTvywIx hhanpMmVNT1uYTX3iKga3Q2Lues+b X-Received: by 2002:a19:7605:0:b0:4f2:7dda:ad06 with SMTP id c5-20020a197605000000b004f27ddaad06mr1213034lff.10.1685617589361; Thu, 01 Jun 2023 04:06:29 -0700 (PDT) X-Google-Smtp-Source: ACHHUZ5MU7Tv6e5AQ/fl9YY7v4y+n271vyDtIh2ZuXcEXxTZQK0FkYBGyVTBJm8HVqCTzB3WDVr95A== X-Received: by 2002:a19:7605:0:b0:4f2:7dda:ad06 with SMTP id c5-20020a197605000000b004f27ddaad06mr1213020lff.10.1685617588940; Thu, 01 Jun 2023 04:06:28 -0700 (PDT) Date: Thu, 1 Jun 2023 07:06:24 -0400 From: "Michael S. Tsirkin" To: Heng Qi Cc: virtio-dev@lists.oasis-open.org, virtio-comment@lists.oasis-open.org, Parav Pandit , Jason Wang , Yuri Benditovich , Xuan Zhuo Message-ID: <20230601070318-mutt-send-email-mst@kernel.org> References: <20230522050236.49433-1-hengqi@linux.alibaba.com> <20230522151522-mutt-send-email-mst@kernel.org> <20230523035803.GB23504@h68b04307.sqa.eu95> <69cd31d4-c059-3edd-f14b-bdf03ac4b200@linux.alibaba.com> <20230530153623-mutt-send-email-mst@kernel.org> <20230601002734-mutt-send-email-mst@kernel.org> <20230601051708.GC98474@h68b04307.sqa.eu95> MIME-Version: 1.0 In-Reply-To: <20230601051708.GC98474@h68b04307.sqa.eu95> X-Mimecast-Spam-Score: 0 X-Mimecast-Originator: redhat.com Content-Type: text/plain; charset=utf-8 Content-Disposition: inline Content-Transfer-Encoding: 8bit Subject: Re: [virtio-dev] Re: [virtio-comment] Re: [PATCH v14] virtio-net: support inner header hash On Thu, Jun 01, 2023 at 01:17:08PM +0800, Heng Qi wrote: > On Thu, Jun 01, 2023 at 12:30:30AM -0400, Michael S. Tsirkin wrote: > > On Tue, May 30, 2023 at 03:40:18PM -0400, Michael S. Tsirkin wrote: > > > On Fri, May 26, 2023 at 04:04:18PM +0800, Heng Qi wrote: > > > > > > > > > > > > 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. > > > > > > How are "tunneling protocols" defined though? > > > > > > Maybe pass a mask of destination UDP ports for which this applies? > > > > > > Then we don't need options, if port is set in mask then > > > generic udp tunnel inner hash applies. If port is not set then > > > hash is calculated in some other way, including > > > one of tunnel specific flags. > > > > I admit this is pretty complex though. As an intermediate step > > I can see two other options: > > - just do this for all UDP packets assuming most traffic is encapsulated > > This is a bit crude, but it does simplify the complexity of device > implementations. > > > - assume that the list of protocols is configured in the NIC > > by other means (e.g. hard-coded, or we can add an admin command for this) > > Other means also means hardcoding, because we always need to know what > the "new tunnel type" is, otherwise the driver can't understand it. > Assuming we don't use any hard-coded tunnel types for the > VIRTIO_NET_F_TUNNEL_HASH feature, then we use the GET command to get the > tunnel types supported by the device before we intend to use the > inner header hashing capabilities. But if we don't do mappings for > these codes, the driver can't understand what the device returns. Then > we need to hardcode it... Yes, if we have a GET command that will need a bitmap anyway, so let's just set a bitmap with a command. > > So I tend to dst port mask, or generic option (set to 1 to use source > port for all UDP packets). > Thanks. Makes sense, and I don't think we need both options. > > > > Thoghts? > > > > > > > > > > > > > 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