From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-wi0-f176.google.com (mail-wi0-f176.google.com [209.85.212.176]) by dpdk.org (Postfix) with ESMTP id 90DE77E75 for ; Thu, 4 Dec 2014 11:45:39 +0100 (CET) Received: by mail-wi0-f176.google.com with SMTP id ex7so34254925wid.9 for ; Thu, 04 Dec 2014 02:45:39 -0800 (PST) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20130820; h=x-gm-message-state:from:to:cc:subject:date:message-id:organization :user-agent:in-reply-to:references:mime-version :content-transfer-encoding:content-type; bh=bJzJgGPweYewKpH4eIE4IE6D6mdoj7rR78kfzyrf9L8=; b=bY5J5lum3tLI2Oo0daODmQchllYdcLd4t0gD2I1cGFpVFaB0/uXyVqgiIPshukXI9h VwpPXwccp75mxIwhrKxCB0QQVwTn3xpYcUYh14nv3KMk6LdO/kzLQq2ROLa+JYoPsJUd alIstTQNNuvzbKTFT1/QJcfx9fLhmG7H817zgKrBsmgx3BjJxjrK9SBIMrdbcgLdW16u kp17zNmWjDt+a6a/35t9wHadDjD7CBxt7HvFcGMy/S6SGFuSVwFqE5HCnuRx5aNs8hQA MxlcHRmDTjHQu2IoR5YeANAYVjxXNCGg45jPkm8MJ96RQG7h+mS9rc4+7DuBHCO4dsG6 fhdg== X-Gm-Message-State: ALoCoQlZrwR5eEHmhva8oeFSZ31oClCuMfQ+h7q1CFqaqxLVRlzidyoVDCr1DAdhws7ePFienEif X-Received: by 10.180.77.170 with SMTP id t10mr110337105wiw.57.1417689939390; Thu, 04 Dec 2014 02:45:39 -0800 (PST) Received: from xps13.localnet (136-92-190-109.dsl.ovh.fr. [109.190.92.136]) by mx.google.com with ESMTPSA id pf4sm39964568wjb.36.2014.12.04.02.45.38 for (version=TLSv1.2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Thu, 04 Dec 2014 02:45:38 -0800 (PST) From: Thomas Monjalon To: "Ananyev, Konstantin" , Olivier MATZ Date: Thu, 04 Dec 2014 11:45:14 +0100 Message-ID: <2324692.x6b6svf072@xps13> Organization: 6WIND User-Agent: KMail/4.14.3 (Linux/3.17.4-1-ARCH; KDE/4.14.3; x86_64; ; ) In-Reply-To: <2601191342CEEE43887BDE71AB977258213BC6F2@IRSMSX105.ger.corp.intel.com> References: <1417532767-1309-1-git-send-email-jijiang.liu@intel.com> <1ED644BD7E0A5F4091CF203DAFB8E4CC01D9FF2B@SHSMSX101.ccr.corp.intel.com> <2601191342CEEE43887BDE71AB977258213BC6F2@IRSMSX105.ger.corp.intel.com> MIME-Version: 1.0 Content-Transfer-Encoding: 7Bit Content-Type: text/plain; charset="us-ascii" Cc: dev@dpdk.org Subject: Re: [dpdk-dev] [PATCH v5 2/3] mbuf:add three TX ol_flags and repalce PKT_TX_VXLAN_CKSUM X-BeenThere: dev@dpdk.org X-Mailman-Version: 2.1.15 Precedence: list List-Id: patches and discussions about DPDK List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Thu, 04 Dec 2014 10:45:39 -0000 Hi, 2014-12-04 10:23, Ananyev, Konstantin: > From: Liu, Jijiang > > From: Olivier MATZ [mailto:olivier.matz@6wind.com] > > > On 12/03/2014 01:59 PM, Ananyev, Konstantin wrote: > > > >> I still think having a flag IPV4 + another flag IP_CHECKSUM is not > > > >> appropriate. > > > > > > > > Sorry, didn't get you here. > > > > Are you talking about our discussion should PKT_TX_IP_CKSUM and > > > > PKT_TX_IPV4 be mutually exclusive or not? > > > > > > Yes > > > > > > >> I though Konstantin agreed on other flags, but I may have > > > >> misunderstood: > > > >> > > > >> http://dpdk.org/ml/archives/dev/2014-November/009070.html > > > > > > > > In that mail, I was talking about my suggestion to make PKT_TX_IP_CKSUM, > > > PKT_TX_IPV4 and PKT_TX_IPV6 to occupy 2 bits. > > > > Something like: > > > > #define PKT_TX_IP_CKSUM (1 << X) > > > > #define PKT_TX_IPV6 (2 << X) > > > > #define PKT_TX_IPV4 (3 << X) > > > > > > > > "Even better, if we can squeeze these 3 flags into 2 bits. > > > > Would save us 2 bits, plus might be handy, as in the PMD you can do: > > > > > > > > switch (ol_flags & TX_L3_MASK) { > > > > case TX_IPV4: > > > > ... > > > > break; > > > > case TX_IPV6: > > > > ... > > > > break; > > > > case TX_IP_CKSUM: > > > > ... > > > > break; > > > > }" > > > > > > > > As you pointed out, it will break backward compatibility. > > > > I agreed with that and self-NACKed it. > > > > > > ok, so we are back between: > > > > > > 1/ (Jijiang's patch) > > > PKT_TX_IP_CKSUM /* packet is IPv4, and we want hw cksum */ > > > PKT_TX_IPV6 /* packet is IPv6 */ > > > PKT_TX_IPV4 /* packet is IPv4, and we don't want hw cksum */ > > > > > > with PKT_TX_IP_CKSUM and PKT_TX_IPV4 exclusive > > > > > > and > > > > > > 2/ > > > PKT_TX_IP_CKSUM /* we want hw IP cksum */ > > > PKT_TX_IPV6 /* packet is IPv6 */ > > > PKT_TX_IPV4 /* packet is IPv4 */ > > > > > > with PKT_TX_IP_CKSUM implies PKT_TX_IPV4 > > > > > > > > > Solution 2/ looks better from a user point of view. Anyone else has an opinion? > > > > Let's think about these IPv4/6 flags in terms of checksum and IP version/type, > > > > 1. For IPv6 > > IP checksum is meaningful only for IPv4, so we define 'PKT_TX_IPV6 /* packet is IPv6 */' to tell driver/HW that this is IPV6 packet, > > here we don't talk about the checksum for IPv6 as it is meaningless. Right? > > > > PKT_TX_IPV6 /* packet is IPv6 */ ------ IP type: v6; HW checksum: meaningless > > > > 2. For IPv4, > > My patch: > > > > PKT_TX_IP_CKSUM /* packet is IPv4, and we want hw cksum */--------------------------IP type: v4; HW checksum: Yes > > PKT_TX_IPV4 /* packet is IPv4, and we don't want hw cksum */ ----------------------- IP type: v4; HW checksum: No > > > > You want: > > PKT_TX_IP_CKSUM /* we want hw IP cksum */-------------------------- IP type: v4; HW checksum: Yes > > PKT_TX_IPV4 /* packet is IPv4*/ ------------------------ IP type: v4; HW checksum: yes or no? > > driver/HW don't know, just know this is packet with IPv4 header. > > HW checksum: meaningless?? > > Yep, that's why I also don't like that suggestion: PKT_TX_IPV4 itself doesn't contain all information. > PMD will have to check PKT_TX_IP_CKSUM anyway. I prefer solution 2 because a flag should bring only 1 information. It's simply saner and could fit to more situations in the future. -- Thomas