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 613D0C7618D for ; Tue, 21 Mar 2023 08:55:45 +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 9076771C87 for ; Tue, 21 Mar 2023 08:55:44 +0000 (UTC) Received: from lists.oasis-open.org (oasis-open.org [10.110.1.242]) by lists.oasis-open.org (Postfix) with ESMTP id 799B398643E for ; Tue, 21 Mar 2023 08:55:44 +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 651BF983DFC; Tue, 21 Mar 2023 08:55:44 +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 52C0598642A for ; Tue, 21 Mar 2023 08:55:44 +0000 (UTC) X-Virus-Scanned: amavisd-new at kavi.com X-MC-Unique: 1BMbOB7QNwCaK0lj5vePKw-1 X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; t=1679388939; h=in-reply-to: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=7PacSmnXL4TMQydi5riVNEXp3mBKs8k3HM8pQJHBYB0=; b=MFAwqPpFmURb6X6R8YRgUV0sytFu1f5YBz/NemseLiz12TJlzIJlHLGjfxIcnlVAcY XyQFArCEM1Wjay/UbsumVeJ3fT3xot8QgXY30eQwYEBgM9UR1tvQlvd0kKC2v+qpmCxH ctqIPFiVGWVJmdzeJzWtAAgYciGz9TMKTJDGtjDk4Wt8jwxY5rDkowmx4ZNgVV1C6R9q ntFX93UcoVL5shgaUMN9LwSFIGYMzL0BRcdtDfD7Pbtl4FH7XcqnalkiLd+6EIgoYo/X nTP1eImxFEM8vvvBFNKyBxjVRitbsNFv1Cr8O5T/YeqSkYvBAvD1SN/9wIww7feBE2kH HjIA== X-Gm-Message-State: AO0yUKU6hFMppB12Sb1rsbm58OHlX2mS4owpOhokCVm/AGEOKSRe1rG9 qh3yAm4xO6oWq4fddntUm0Fo9YfRwznz/BllNX3iqmeNIAmvfJmwQ5JJ7yod1LhwjmPVhEXl+10 SbEWJMK3P5IJRwkhcECIxwevp49jK X-Received: by 2002:a5d:590f:0:b0:2ce:50bb:dd11 with SMTP id v15-20020a5d590f000000b002ce50bbdd11mr1564928wrd.27.1679388939174; Tue, 21 Mar 2023 01:55:39 -0700 (PDT) X-Google-Smtp-Source: AK7set/iXIk/CB+CPx6plc6hTiQQ6ELaxlVGAtvgHUwLDfbHIqqyKbDOE5PFL0ZrD9dou4UUEsiHZQ== X-Received: by 2002:a5d:590f:0:b0:2ce:50bb:dd11 with SMTP id v15-20020a5d590f000000b002ce50bbdd11mr1564913wrd.27.1679388938881; Tue, 21 Mar 2023 01:55:38 -0700 (PDT) Date: Tue, 21 Mar 2023 04:55:34 -0400 From: "Michael S. Tsirkin" To: Parav Pandit Cc: virtio-dev@lists.oasis-open.org, pasic@linux.ibm.com, cohuck@redhat.com, virtio-comment@lists.oasis-open.org, shahafs@nvidia.com Message-ID: <20230321044737-mutt-send-email-mst@kernel.org> References: <20230321041036.201439-1-parav@nvidia.com> <20230321041036.201439-8-parav@nvidia.com> MIME-Version: 1.0 In-Reply-To: <20230321041036.201439-8-parav@nvidia.com> X-Mimecast-Spam-Score: 0 X-Mimecast-Originator: redhat.com Content-Type: text/plain; charset=us-ascii Content-Disposition: inline Subject: [virtio-dev] Re: [PATCH v2 7/7] virtio-net: Describe RSS using receive queue handle On Tue, Mar 21, 2023 at 06:10:36AM +0200, Parav Pandit wrote: > The content of indirection table and unclassified_queue which are > based on math calculation historically. To better describe this, to > avoid intermixing array index with virtqueue index and to use virtqueue > number > > introduce a field rq_handle (receive queue handle) and refer them > to describe unclassified_queue and indirection_table fields. > > As part of it, have the example that uses non zero virtqueue > number which helps to have better mapping between receiveX > object with virtqueue number and the actual value in the > indirection table. > > Fixes: https://github.com/oasis-tcs/virtio-spec/issues/163 > Signed-off-by: Parav Pandit > > --- > changelog: > v0->v1: > - new patch suggested by Michael Tsirkin > --- > device-types/net/description.tex | 24 +++++++++++++++++++----- > 1 file changed, 19 insertions(+), 5 deletions(-) > > diff --git a/device-types/net/description.tex b/device-types/net/description.tex > index 435c1fc..fa9b4c7 100644 > --- a/device-types/net/description.tex > +++ b/device-types/net/description.tex > @@ -1442,20 +1442,32 @@ \subsubsection{Control Virtqueue}\label{sec:Device Types / Network Device / Devi > \field{indirection_table} array. > Number of entries in \field{indirection_table} is (\field{indirection_table_mask} + 1). > > -Field \field{unclassified_queue} contains the 0-based index of > -the receive virtqueue to place unclassified packets in. Index 0 corresponds to receiveq1. > +Field \field{unclassified_queue} contains the receive queue > +handle \field{rq_handle} described below. > > -Field \field{indirection_table} contains an array of 0-based indices of receive virtqueues. Index 0 corresponds to receiveq1. > +Field \field{indirection_table} contains an array of receive > +queue handles described below in \field{rq_handle}. This is only used once, here. I understand that we need a name for this but it need not be so generic, I feel it's just confusing. I propose "indirection table entry". Thus: Field \field{indirection_table} contains an array of indirection table entries. Each indirection table entry consists of a vq number value divided by 2. Thus, an entry value of 3 maps to virtqueue number 6 which corresponds to receiveq4 > For example at > +array index 0, why mention array index here? > a value of 3 maps to virtqueue number 6 > +which corresponds to receiveq4. It's a good idea to first describe a concept then provide an example. > A driver sets \field{max_tx_vq} to inform a device how many transmit virtqueues it may use (transmitq1\ldots transmitq \field{max_tx_vq}). > > Fields \field{hash_key_length} and \field{hash_key_data} define the key to be used in hash calculation. > > +\begin{lstlisting} > +le16 rq_handle; > +\end{lstlisting} > + > +\field{rq_handle} is a receive virtqueue handle. It is calculated as > +virtqueue number divided by 2. For example a receive virtqueue handle > +value of 3 corresponds to virtqueue number 6 maps to receiveq4. > + it's a bit disconnected from the rest of the description. why not adjacent to it? > \drivernormative{\subparagraph}{Setting RSS parameters}{Device Types / Network Device / Device Operation / Control Virtqueue / Receive-side scaling (RSS) } > > A driver MUST NOT send the VIRTIO_NET_CTRL_MQ_RSS_CONFIG command if the feature VIRTIO_NET_F_RSS has not been negotiated. > > -A driver MUST fill the \field{indirection_table} array only with indices of enabled queues. Index 0 corresponds to receiveq1. > +A driver MUST fill the \field{indirection_table} array only with > +the \field{rq_handle} corresponding to the enabled receive virtqueues. > > The number of entries in \field{indirection_table} (\field{indirection_table_mask} + 1) MUST be a power of two. > > @@ -1468,7 +1480,9 @@ \subsubsection{Control Virtqueue}\label{sec:Device Types / Network Device / Devi > \begin{itemize} > \item Calculate the hash of the packet as defined in \ref{sec:Device Types / Network Device / Device Operation / Processing of Incoming Packets / Hash calculation for incoming packets}. > \item If the device did not calculate the hash for the specific packet, the device directs the packet to the receiveq specified by \field{unclassified_queue} of virtio_net_rss_config structure. > -\item Apply \field{indirection_table_mask} to the calculated hash and use the result as the index in the indirection table to get 0-based number of destination receiveq. > +\item Apply \field{indirection_table_mask} to the calculated hash > +and use the result as the index in the indirection table to get > +\field{rq_handle}. > \item If the destination receive queue is being reset (See \ref{sec:Basic Facilities of a Virtio Device / Virtqueues / Virtqueue Reset}), the device MUST drop the packet. > \end{itemize} > > -- > 2.26.2 --------------------------------------------------------------------- To unsubscribe, e-mail: virtio-dev-unsubscribe@lists.oasis-open.org For additional commands, e-mail: virtio-dev-help@lists.oasis-open.org