From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-wr0-f170.google.com (mail-wr0-f170.google.com [209.85.128.170]) by dpdk.org (Postfix) with ESMTP id 898116932 for ; Tue, 21 Feb 2017 10:54:14 +0100 (CET) Received: by mail-wr0-f170.google.com with SMTP id 89so74078584wrr.3 for ; Tue, 21 Feb 2017 01:54:14 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=6wind-com.20150623.gappssmtp.com; s=20150623; h=from:date:to:cc:subject:message-id:in-reply-to:references :mime-version:content-transfer-encoding; bh=HENfT3dOYiU4vQzK2lG27e9Y+XxPLiGc79hM0Vpcquc=; b=wVXDGeFnsPwOsj3Hz6DBdGK9M3QJZP1u6F9bBZZUtbkJFUsoE04rX9MfdyK/RPoTqq Fxl5MmAICVuCs4HsZX27C8ir43VdYgi6X8HegixZuNl/zXkiTbwKWpXg2U4BuXzd36vV nPR3tXYjVbycfTikOTUgh0cdNf0vwVNhsmK9HDvQHr0FKgFUSyoIPyj2M33d9nsSyqJo OhO1ZbpnMRhfA7A2YxanywN5kqk7xhAiFkVByhBvkP9O7LB6kfEZ0okwoWCRguKqME+N LSVN1WcQXNp6zaHC+a5ZsojWspDL/nw6OR8aWEWCzlJdaz5ChdbOj6yDusp9MXPIIo38 Ugvg== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:from:date:to:cc:subject:message-id:in-reply-to :references:mime-version:content-transfer-encoding; bh=HENfT3dOYiU4vQzK2lG27e9Y+XxPLiGc79hM0Vpcquc=; b=CT+jl8RrsD6HOQVbacY/c55vfwWzMwkraqjrZb8Y7fdnUqaV8YSpZOUOII+ytDv10U mMn8rWfDHZAKpzPapGTGOi5G8Xx/rnJt1qFZrp6gWo2aiIzcY+7bApElIhpGhgmHDWPC Cmzzu3w7lu/k8UNCuzYiYPlGRCqCsmD6qSwREX3dsDX49sCiJWrgZipDth8fcH1BmdXu RHa6GYaz9hPONn6xQiWLavCtz9YQiEtXZu4eZwSqZILdR+HjH0kdp8brtAnBBASS/4Gw 75CClqBcpM/FDDSGYmU6a27BjDbccCqfz7kj+ho+6MPWOFVADiMPJRWuliObvWxnaccP AkEw== X-Gm-Message-State: AMke39ntYnb4zQoSaE6ol+1iwUu8sq54Vorn5SQGNvGmGyVwG3EyGhWLG+Qsyo009mvy3DOp X-Received: by 10.223.142.107 with SMTP id n98mr16780667wrb.11.1487670854321; Tue, 21 Feb 2017 01:54:14 -0800 (PST) Received: from glumotte.dev.6wind.com (host.78.145.23.62.rev.coltfrance.com. [62.23.145.78]) by smtp.gmail.com with ESMTPSA id e73sm16945617wmi.32.2017.02.21.01.54.14 (version=TLS1_2 cipher=ECDHE-RSA-CHACHA20-POLY1305 bits=256/256); Tue, 21 Feb 2017 01:54:14 -0800 (PST) From: Olivier MATZ X-Google-Original-From: Olivier MATZ Date: Tue, 21 Feb 2017 10:54:06 +0100 To: Morten =?UTF-8?B?QnLDuHJ1cA==?= Cc: "Olivier Matz" , Message-ID: <20170221105406.39045e99@glumotte.dev.6wind.com> In-Reply-To: <98CBD80474FA8B44BF855DF32C47DC359EAD04@smartserver.smartshare.dk> References: <1485271173-13408-1-git-send-email-olivier.matz@6wind.com> <2601191342CEEE43887BDE71AB9772583F111A29@irsmsx105.ger.corp.intel.com> <20170216144807.7add2c71@platinum> <98CBD80474FA8B44BF855DF32C47DC359EAD04@smartserver.smartshare.dk> X-Mailer: Claws Mail 3.14.1 (GTK+ 2.24.30; x86_64-pc-linux-gnu) MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: quoted-printable Subject: Re: [dpdk-dev] [RFC 0/8] mbuf: structure reorganization 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: , X-List-Received-Date: Tue, 21 Feb 2017 09:54:14 -0000 Hi Morten, On Tue, 21 Feb 2017 10:22:57 +0100, Morten Br=C3=B8rup wrote: > Hi Olivier, >=20 > There has been a lot of debate about the size and location (1st or > 2nd cache line) of the mbuf fields. >=20 > May I suggest that you add a comment to each field briefly mentioning > why it has a specific size (8 or 16 bits) (e.g. by example use case), > and optionally also why it deserves to be in the first cache line. (A > comment to the mbuf structure can say that fields manipulated by PMDs > on ingress generally belong in the 1st cache line.) >=20 > It's not necessary for all fields, just the non-obvious ones (the > ones discussed here on the mailing list). It will make the > information more easily accessible to avoid repeating the same > discussions in the future. >=20 > E.g. the port field is 16 bits because a hypervisor can serve more > than 256 virtual machines. And it is in the 1st cache line because a > PMD for a multi-port NIC with a shared ingress queue needs to set it > on ingress. >=20 > And the refcnt field has the same size as the port field to support > L3 multicast and L2 port flooding on all ports. >=20 I understand your point about not rediscussing things several times. I don't think having a comment for fields is really relevant because it would add many info that are not useful for the user of the structure, but I think adding something in the API documentation of the rte_mbuf structure itself makes sense to me. I'll add something in the next version of the patch. Thanks, Olivier