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 9B7ADEB64D9 for ; Tue, 4 Jul 2023 06:56:49 +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 0F2F84256B for ; Tue, 4 Jul 2023 06:56:49 +0000 (UTC) Received: from lists.oasis-open.org (oasis-open.org [10.110.1.242]) by lists.oasis-open.org (Postfix) with ESMTP id 064C3986566 for ; Tue, 4 Jul 2023 06:56:49 +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 EC03E986559; Tue, 4 Jul 2023 06:56:48 +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 CDA1E98655E for ; Tue, 4 Jul 2023 06:56:40 +0000 (UTC) X-Virus-Scanned: amavisd-new at kavi.com X-MC-Unique: v9itGXhRNwOx23K7q02JFw-1 From: Cornelia Huck To: "Michael S. Tsirkin" , Heng Qi Cc: virtio-comment@lists.oasis-open.org, virtio-dev@lists.oasis-open.org, Parav Pandit , Jason Wang , Yuri Benditovich , Xuan Zhuo In-Reply-To: <20230703114640-mutt-send-email-mst@kernel.org> Organization: Red Hat GmbH References: <20230703152711.106008-1-hengqi@linux.alibaba.com> <20230703114640-mutt-send-email-mst@kernel.org> User-Agent: Notmuch/0.37 (https://notmuchmail.org) Date: Tue, 04 Jul 2023 08:56:34 +0200 Message-ID: <87cz18i2ql.fsf@redhat.com> MIME-Version: 1.0 X-Scanned-By: MIMEDefang 3.1 on 10.11.54.10 X-Mimecast-Spam-Score: 0 X-Mimecast-Originator: redhat.com Content-Type: text/plain Subject: [virtio-dev] Re: [PATCH v21] virtio-net: support inner header hash On Mon, Jul 03 2023, "Michael S. Tsirkin" wrote: > On Mon, Jul 03, 2023 at 11:27:11PM +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. >> >> Fixes: https://github.com/oasis-tcs/virtio-spec/issues/173 >> Signed-off-by: Heng Qi >> Reviewed-by: Xuan Zhuo >> Reviewed-by: Parav Pandit > > Cornelia last minute comments before I start a vote? Please just go ahead. --------------------------------------------------------------------- To unsubscribe, e-mail: virtio-dev-unsubscribe@lists.oasis-open.org For additional commands, e-mail: virtio-dev-help@lists.oasis-open.org