From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: <thomas.monjalon@6wind.com> Received: from mail-wm0-f51.google.com (mail-wm0-f51.google.com [74.125.82.51]) by dpdk.org (Postfix) with ESMTP id C42155937 for <dev@dpdk.org>; Mon, 27 Jun 2016 11:05:10 +0200 (CEST) Received: by mail-wm0-f51.google.com with SMTP id r201so105051236wme.1 for <dev@dpdk.org>; Mon, 27 Jun 2016 02:05:10 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=6wind-com.20150623.gappssmtp.com; s=20150623; h=from:to:cc:subject:date:message-id:user-agent:in-reply-to :references:mime-version:content-transfer-encoding; bh=j2LYcLN3lLsyo3Tt4GrdtXinEGQXtOybLtHRMj0O+pU=; b=imbbwgwW+PjlFuoXmNE5Pu/aYP++/Mrw/b+COR6ch5B8Zf71Gm5XeukhZeLjB427Oh XzN/E/xx+Hf98m8AdsCHibXAIoS6DjRkUWAYdD7FpKspWJIWMQ6a/98zc4NLq0Gnjxwh li6Y9AYJ8vpKeuHaAgwTe7SAza/jFWbQkBwMNtsrpDfcgZ+OuUPsGHHQ/bAQypYScAk7 HuGvPpYOuxgyvTmjFvyMizg88rNrDdie1Bd3WoAwCqQq39hQJZHgrFa/htUQpFMr9eYj O9AkQZYAx3GufVakwrIC4bMDy1JxAPNK75UvWppw81wj2C/r9f55aOzatY5svbYhgsxt 0uMQ== 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:user-agent :in-reply-to:references:mime-version:content-transfer-encoding; bh=j2LYcLN3lLsyo3Tt4GrdtXinEGQXtOybLtHRMj0O+pU=; b=O7NYh932mo+Qrb+YAIErKf+yXrkEo0C+I4a8Y+U5OaBeGsnVr51EvKjzbqxZg3gI/l 1i9IJl8ssU6JWAJU/nwUYv7or7OJM050Jx8Uo8n4fYTRO0PN+bMsfnMZoVlUvfrh4uR7 t1Mk3xmrL7HsOmsEOPKgJP5zCuSAQLaomw/WKrjrqO0UFtT3zvniIO5FrYzznfZWCZEl jFmJdqzZdn/AlAoZA1zHOchS1zfYRFMHWpqFBflEkB4Vj/XRVNEmzqjm0AG5mKEofjEY OAzGhYFVQM0drWihIcnd9mntDhpBejWwI0PcOeGAXa+FtRuIrzZAe9aarayXRbcDBmHl 2Wew== X-Gm-Message-State: ALyK8tLdiv3hrMuqZh3x2GI7nC8KslWiO+uzv9dMkfsgCL6eQW28tDykbfW02NP4j74vNvSr X-Received: by 10.28.199.139 with SMTP id x133mr8831924wmf.45.1467018310595; Mon, 27 Jun 2016 02:05:10 -0700 (PDT) Received: from xps13.localnet (184.203.134.77.rev.sfr.net. [77.134.203.184]) by smtp.gmail.com with ESMTPSA id b84sm10675803wmb.6.2016.06.27.02.05.09 (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Mon, 27 Jun 2016 02:05:09 -0700 (PDT) From: Thomas Monjalon <thomas.monjalon@6wind.com> To: "Wiles, Keith" <keith.wiles@intel.com> Cc: dev@dpdk.org, Olivier Matz <olivier.matz@6wind.com>, "Ananyev, Konstantin" <konstantin.ananyev@intel.com> Date: Mon, 27 Jun 2016 11:05:09 +0200 Message-ID: <1706546.bAg9N1Gdxd@xps13> User-Agent: KMail/4.14.10 (Linux/4.5.4-1-ARCH; KDE/4.14.11; x86_64; ; ) In-Reply-To: <5770E365.4060703@6wind.com> References: <1466868582-66201-1-git-send-email-keith.wiles@intel.com> <2601191342CEEE43887BDE71AB97725836B7715C@irsmsx105.ger.corp.intel.com> <5770E365.4060703@6wind.com> MIME-Version: 1.0 Content-Transfer-Encoding: 7Bit Content-Type: text/plain; charset="us-ascii" Subject: Re: [dpdk-dev] [PATCH v2] mbuf:rearrange mbuf to be more mbuf chain friendly X-BeenThere: dev@dpdk.org X-Mailman-Version: 2.1.15 Precedence: list List-Id: patches and discussions about DPDK <dev.dpdk.org> List-Unsubscribe: <http://dpdk.org/ml/options/dev>, <mailto:dev-request@dpdk.org?subject=unsubscribe> List-Archive: <http://dpdk.org/ml/archives/dev/> List-Post: <mailto:dev@dpdk.org> List-Help: <mailto:dev-request@dpdk.org?subject=help> List-Subscribe: <http://dpdk.org/ml/listinfo/dev>, <mailto:dev-request@dpdk.org?subject=subscribe> X-List-Received-Date: Mon, 27 Jun 2016 09:05:10 -0000 2016-06-27 10:27, Olivier Matz: > On 06/27/2016 10:21 AM, Ananyev, Konstantin wrote: > > From: dev [mailto:dev-bounces@dpdk.org] On Behalf Of Keith Wiles > >> Move the next pointer to the first cacheline of the rte_mbuf structure > >> and move the offload values to the second cacheline to give better > >> performance to applications using chained mbufs. > >> > >> Enabled by a configuration option CONFIG_RTE_MBUF_CHAIN_FRIENDLY default > >> is set to No. > > > > First, it would make ixgbe and i40e vector RX functions to work incorrectly. > > Second, I don't think we can afford to allow people swap mbuf fields in the way they like. > > Otherwise we'll end-up with totally unmaintainable code pretty soon. > > So NACK. > > +1 To be more precise, the arrangement of fields in rte_mbuf is open to debate and changes. There is a recent discussion here: http://dpdk.org/ml/archives/dev/2016-May/039483.html I think we must try to improve few things in mbuf during the 16.11 cycle. But it must not be allowed to have a build option to adapt this structure or any other API. There is only one DPDK API for a given version.