From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-wi0-f178.google.com (mail-wi0-f178.google.com [209.85.212.178]) by dpdk.org (Postfix) with ESMTP id 497708DA1 for ; Wed, 14 Oct 2015 16:36:50 +0200 (CEST) Received: by wijq8 with SMTP id q8so84780951wij.0 for ; Wed, 14 Oct 2015 07:36:50 -0700 (PDT) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20130820; h=x-gm-message-state:message-id:date:from:organization:user-agent :mime-version:to:subject:references:in-reply-to:content-type :content-transfer-encoding; bh=2q8ceQW3ZShqHe+92gAVi5EToAPCx3qJtdeadvzHsGA=; b=k158DnhTh8fW9FQ7Ff5W/3S//23GU1k2PBllYDIXt2zpI4Q1xhc7pszUSOcOxwl4cI +7zrTsAPNrnDRx5iHcwhUjWYlOKooMMSGDZFyPEfou/sFR23cnIkCggd5ELG7XC+2LfO z94Cq2qeEaibYk0p/z7n9kHJzhe2BnXR/AzLD4FUd9DGUVAqOeh+f/aIpaIeMxRlwonG 5wAy8IeI5hva5BBnw9lAIxIjsG734H7+PmJh9bEIFgx6vh2E8wwelJ3Fjh5RRNmWNz8M aij3BM3fgdtUcbLqGitABgLv9hBmlPVZgWjc07iIzeu/NUGT+j/uwca/KyPSAQknvFcN BQCA== X-Gm-Message-State: ALoCoQnvPzPz6w5hdy0nCiAQ+ne1Nu5uMFmKOF85369BcbAa54Mj3p0Hrm9l2fAU1y0L/yZLsI01 X-Received: by 10.194.234.97 with SMTP id ud1mr4536307wjc.133.1444833388290; Wed, 14 Oct 2015 07:36:28 -0700 (PDT) Received: from saturne.dev.6wind.com (guy78-3-82-239-227-177.fbx.proxad.net. [82.239.227.177]) by smtp.gmail.com with ESMTPSA id gc14sm7401244wic.12.2015.10.14.07.36.27 (version=TLSv1.2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Wed, 14 Oct 2015 07:36:27 -0700 (PDT) Message-ID: <561E686B.4050902@6wind.com> Date: Wed, 14 Oct 2015 16:36:27 +0200 From: Vincent JARDIN Organization: www.6wind.com User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:31.0) Gecko/20100101 Thunderbird/31.5.0 MIME-Version: 1.0 To: "Mcnamara, John" , Thomas F Herbert , "dev@dpdk.org" References: <5616B611.3070900@redhat.com> In-Reply-To: Content-Type: text/plain; charset=utf-8; format=flowed Content-Transfer-Encoding: 7bit Subject: Re: [dpdk-dev] DPDK User Space: Session onUseability and Ease of Use 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: Wed, 14 Oct 2015 14:36:50 -0000 Thomas, John, thanks for your notes. Enclosed the contents of our chats, On 13/10/2015 18:36, Mcnamara, John wrote: > * PMD lite > > - Do we need a lighter PMD model? Perhaps based on the Mellanox > model. > - Vincent suggested be could remove 90% of the code. I'll leave > Vincent explain this one. benefits of 100% userland drivers: - no dependency on getting kernel patch upstreams first - it is possible to run on a latest HW even when the Linux host (or host OS) does not support the new NIC/boards supported by the DPDK drawbacks of 100% userland drivers: - redundancy of source code (duplication into the kernel and userland) => more maintenance - DPDK PMDs are in fact outdated while kernel drivers are supporting latest HW (port management - optics - , latest HW revisions, managing firmware updates) more frequently - do not run when not root applications - cannot reuse port management tools from the kernels (ethtool, etc.) ixgbe pmd ========= 100% lines of userland must be run as root ~ 40K lines ~ kernel overlaps with http://dpdk.org/browse/dpdk/tree/drivers/net/ixgbe/base ~ mostly only http://dpdk.org/browse/dpdk/tree/drivers/net/ixgbe/ixgbe_rxtx[_vec].c is needed, other files are not needed (6k lines of code) mlx4 pmd ======== 10% lines userland, then using kernel's ones could be run as a non root process ~ 5.2K lines of code ~ the rxtx.c file is http://dpdk.org/browse/dpdk/tree/drivers/net/mlx4/ BUT using infiniband :( => should be cleand up to use bare minimum like, + /* Allocate protection domain. */ http://dpdk.org/browse/dpdk/tree/drivers/net/mlx4/mlx4.c#n4828 + Register memory regions -> ibv_reg_mr() http://dpdk.org/browse/dpdk/tree/drivers/net/mlx4/mlx4.c#n792 Best regards, Vincent