From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: <avi@cloudius-systems.com> Received: from mail-wm0-f42.google.com (mail-wm0-f42.google.com [74.125.82.42]) by dpdk.org (Postfix) with ESMTP id 017986A6F for <dev@dpdk.org>; Mon, 29 Feb 2016 10:43:32 +0100 (CET) Received: by mail-wm0-f42.google.com with SMTP id l68so28406685wml.0 for <dev@dpdk.org>; Mon, 29 Feb 2016 01:43:32 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=scylladb-com.20150623.gappssmtp.com; s=20150623; h=subject:to:references:from:message-id:date:user-agent:mime-version :in-reply-to:content-transfer-encoding; bh=aBD2u5noJ/6LL+OKpPqHHUDr1pGkJsieH+DNUjVmiTo=; b=CFgGcxRpm3pAcIemI6z+WIBI3j05GSqYE99N7hojxbt2JMNdpWbfUE2ImoPOcb+6Hw YQ3hvgDounoXnSzeJaH4JGrajqK9vRwM27FgKW3KaNGun2wkAppyfl9N6g2AgelmJO+1 JRqsmgBNxATv07bXn4l38gIvGutrRRpHdF7iXRDR53lYkYhgiploLJRyV0Sk6HErJqIa P7FmZewGAW9UQIVHHX//jimp/aRhjdHPoyBDINDZL4PtzQPH4i5ny15ksUCnYnKErEKk raLWH0dOMrkseRC68Ex1x89kqBV5FokzgTJuOklgKBNnW3b76KWU72Ig21HQJ4JixSjl E6bg== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20130820; h=x-gm-message-state:subject:to:references:from:message-id:date :user-agent:mime-version:in-reply-to:content-transfer-encoding; bh=aBD2u5noJ/6LL+OKpPqHHUDr1pGkJsieH+DNUjVmiTo=; b=LrmDg0x50qa7x/oqNupF8lqL0gpLBqHOkfx+evAk3dVOFQH86YOG1yH/5kUOTw2C0O Fckx6qGYcWRQjIztIEuKj8gWMvVLeZaclssJodnyVuINOI60p61puGWihvQ+/72QEDRg hzCotxYt2zV+9tfpDCSao9jG1UViNz1bVQ0Wl2Myi7M1o7xgQ+DNCvp4xDlfEPyolevS 64HHFOTkgZDu96ptguMIZPjFXBXTMNQRH4avOvbJmZTVTpCRrN17Wm0pId/EbPs3OwUb z1Q6BjbLSUM4rSJWvumhJHmC8391jlIIckEjHRFIrTgcyP5xSLN0fv3Sz/tBXD1e9T5F mpzQ== X-Gm-Message-State: AD7BkJJlOFWLNZkzYmV5wMr6QdavbrperIuOzjaiLsxqZxMLudFIl9m0Y6GaKBLsGLuUQQ== X-Received: by 10.28.129.194 with SMTP id c185mr10745850wmd.29.1456739011854; Mon, 29 Feb 2016 01:43:31 -0800 (PST) Received: from avi.cloudius-systems.com ([37.142.229.250]) by smtp.googlemail.com with ESMTPSA id ei9sm25135131wjd.40.2016.02.29.01.43.30 (version=TLSv1/SSLv3 cipher=OTHER); Mon, 29 Feb 2016 01:43:31 -0800 (PST) To: Ferruh Yigit <ferruh.yigit@intel.com>, dev@dpdk.org References: <1453911849-16562-1-git-send-email-ferruh.yigit@intel.com> <1453911849-16562-2-git-send-email-ferruh.yigit@intel.com> <56D3137D.1090106@scylladb.com> <56D3559F.2000100@intel.com> From: Avi Kivity <avi@scylladb.com> Message-ID: <56D412C2.5050806@scylladb.com> Date: Mon, 29 Feb 2016 11:43:30 +0200 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:38.0) Gecko/20100101 Thunderbird/38.6.0 MIME-Version: 1.0 In-Reply-To: <56D3559F.2000100@intel.com> Content-Type: text/plain; charset=windows-1252; format=flowed Content-Transfer-Encoding: 7bit Subject: Re: [dpdk-dev] [PATCH 1/3] kcp: add kernel control path kernel module 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, 29 Feb 2016 09:43:32 -0000 On 02/28/2016 10:16 PM, Ferruh Yigit wrote: > On 2/28/2016 3:34 PM, Avi Kivity wrote: >> On 01/27/2016 06:24 PM, Ferruh Yigit wrote: >>> This kernel module is based on KNI module, but this one is stripped >>> version of it and only for control messages, no data transfer >>> functionality provided. >>> >>> This Linux kernel module helps userspace application create virtual >>> interfaces and when a control command issued into that virtual >>> interface, module pushes the command to the userspace and gets the >>> response back for the caller application. >>> >>> The Linux tools like ethtool/ifconfig/ip can be used on virtual >>> interfaces but not ones for related data, like tcpdump. >>> >>> In long term this patch intends to replace the KNI and KNI will be >>> depreciated. >> Instead of adding yet another out-of-tree kernel module, why not extend >> the existing in-tree tap driver? This will make everyone's life easier. >> >> Since tap also supports data transfer, an application can also forward >> packets not intended to it to the kernel, and forward packets from the >> kernel through the device. >> > Hi Avi, > > KDP (Kernel Data Path) does what you have described, it is implemented > as PMD and it benefits from tap driver to data transfer through the > kernel. It also support custom kernel module for better performance. > > For KCP (Kernel Control Path), network driver forwards control commands > to the userspace driver, I doubt this is something wanted for tun/tap > driver, so extending tun/tap driver like this can be hard to upstream. Have you tried asking? Maybe if you explain it they will be open to the extension. Certainly it will be better to have KCP and KDP use the same kernel interface name; so we'll need to either add data path support to kcp (causing duplication with tap), or add control path support to tap. I think the latter is preferable. > We are investigating about adding a native support to Linux kernel for > KCP, but there is no task started for this right now, any support is > welcome. > >