From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from dpdk.org (dpdk.org [92.243.14.124]) by inbox.dpdk.org (Postfix) with ESMTP id D5E84A04C0; Mon, 28 Sep 2020 09:31:47 +0200 (CEST) Received: from [92.243.14.124] (localhost [127.0.0.1]) by dpdk.org (Postfix) with ESMTP id 122BB1C1E6; Mon, 28 Sep 2020 09:31:45 +0200 (CEST) Received: from us-smtp-delivery-124.mimecast.com (us-smtp-delivery-124.mimecast.com [216.205.24.124]) by dpdk.org (Postfix) with ESMTP id 347B51BC1C for ; Mon, 28 Sep 2020 09:31:42 +0200 (CEST) Dkim-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1601278300; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=zqkGcDW03BPW55QOid6JKWG9NKc0aDcnZdGsGR4I5CY=; b=D0uQoXsPEmD2/SUi3YOtXcswd2XnYXfRjc9kOChsc487k5925HhvfJlOoD3ltNSxVbhrPO /GvFq3yufH4Lz81CdJM8wqZBvARrWK56ykQ2OFj0vYTE9FhMVEG/6JZ8x6QSequYKGj0N4 Kqf5dRuUh0Op+PBqUKggzr6whmvnL6c= Received: from mail-wm1-f71.google.com (mail-wm1-f71.google.com [209.85.128.71]) (Using TLS) by relay.mimecast.com with ESMTP id us-mta-377-4Elvf8q1MiiD_5FQbD1LsQ-1; Mon, 28 Sep 2020 03:31:38 -0400 X-MC-Unique: 4Elvf8q1MiiD_5FQbD1LsQ-1 Received: by mail-wm1-f71.google.com with SMTP id x81so32499wmg.8 for ; Mon, 28 Sep 2020 00:31:38 -0700 (PDT) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:subject:to:cc:references:from:message-id:date :user-agent:mime-version:in-reply-to:content-language :content-transfer-encoding; bh=zqkGcDW03BPW55QOid6JKWG9NKc0aDcnZdGsGR4I5CY=; b=obaJTk61BJChmUWbR6G5qLkAgaBY2i2BY5mU3447lXbhs5y07mOCo/eBR7hESktIW0 o01pzU8ymKjku6SeKMOd17PY3WkTor5hfW1x1cNF8M+EWCFQCzVB0PrC5qD1LzDpCc3z oIDrkfvyou1GUEaC5PyswPIBAybsw9Mq22f4anKLEsD/mDWWgZZvNsU42gV+dDeYDMo7 hc/25pOEDZw+35vc3IhZh/SgYYX1YgLFnL8FT1/48DVNkVqx9UpHZ+HFRRQC3GNqadda jxsVRzGJW7cAwc/q0WSWEnOTZyThvfji+Q9v8CdIolN7kg4pQqCfq+NV6qhvUUa5t5Gx RwgQ== X-Gm-Message-State: AOAM531Hq0vlIAKkOqII7nBSz1CGySUgXx4kSJn+Jk1uWmgppMnITbQA xVpkw/IvFXMoDbn0bHJuPja46AkLcCbwduF6EQI6+MmrpK5isQnEXA+6Va3UgTDHPKqaI54bMck SolY= X-Received: by 2002:a1c:a444:: with SMTP id n65mr177176wme.122.1601278297765; Mon, 28 Sep 2020 00:31:37 -0700 (PDT) X-Google-Smtp-Source: ABdhPJztTjokhU5a/CIA/dTUwS5uUuAxOaR5ujZxpiZeiLURGahpWhcjmISiFXn2aZU+GH/VM/Av2w== X-Received: by 2002:a1c:a444:: with SMTP id n65mr177163wme.122.1601278297567; Mon, 28 Sep 2020 00:31:37 -0700 (PDT) Received: from dceara.remote.csb (i87195.upc-i.chello.nl. [62.195.87.195]) by smtp.gmail.com with ESMTPSA id d13sm177309wrp.44.2020.09.28.00.31.36 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Mon, 28 Sep 2020 00:31:36 -0700 (PDT) To: Ferruh Yigit , dev@dpdk.org Cc: bruce.richardson@intel.com References: <1600425415-31834-1-git-send-email-dceara@redhat.com> <40128dc3-e379-6916-67fa-69b4394cac0a@intel.com> From: Dumitru Ceara Message-ID: <4210e299-3af5-63b2-717c-7495ba38822b@redhat.com> Date: Mon, 28 Sep 2020 09:31:35 +0200 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:68.0) Gecko/20100101 Thunderbird/68.6.0 MIME-Version: 1.0 In-Reply-To: <40128dc3-e379-6916-67fa-69b4394cac0a@intel.com> Authentication-Results: relay.mimecast.com; auth=pass smtp.auth=CUSA124A263 smtp.mailfrom=dceara@redhat.com X-Mimecast-Spam-Score: 0 X-Mimecast-Originator: redhat.com Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 7bit Subject: Re: [dpdk-dev] [PATCH] net/ring: advertise multi segment support. X-BeenThere: dev@dpdk.org X-Mailman-Version: 2.1.15 Precedence: list List-Id: DPDK patches and discussions List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: dev-bounces@dpdk.org Sender: "dev" On 9/22/20 4:21 PM, Ferruh Yigit wrote: > On 9/18/2020 11:36 AM, Dumitru Ceara wrote: >> Even though ring interfaces don't support any other TX/RX offloads they >> do support sending multi segment packets and this should be advertised >> in order to not break applications that use ring interfaces. >> > > Does ring PMD support sending multi segmented packets? > Yes, sending multi segmented packets works fine with ring PMD. > As far as I can see ring PMD doesn't know about the mbuf segments. > Right, the PMD doesn't care about the mbuf segments but it implicitly supports sending multi segmented packets. From what I see it's actually the case for most of the PMDs, in the sense that most don't even check the DEV_TX_OFFLOAD_MULTI_SEGS flag and if the application sends multi segment packets they are just accepted. However, the fact that the ring PMD doesn't advertise this implicit support forces applications that use ring PMD to have a special case for handling ring interfaces. If the ring PMD would advertise DEV_TX_OFFLOAD_MULTI_SEGS this would allow upper layers to be oblivious to the type of underlying interface. Thanks, Dumitru