From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-la0-x231.google.com (mail-la0-x231.google.com [IPv6:2a00:1450:4010:c03::231]) by dpdk.org (Postfix) with ESMTP id 7FEF62A9 for ; Fri, 13 Dec 2013 04:10:10 +0100 (CET) Received: by mail-la0-f49.google.com with SMTP id er20so953840lab.36 for ; Thu, 12 Dec 2013 19:11:15 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20120113; h=mime-version:in-reply-to:references:date:message-id:subject:from:to :cc:content-type; bh=X4nELw7M9Un0uQHrgaavbBVEmuhNDVl+T9NtwhylNWo=; b=D285AUn0FA8jwTnegTQP7YECtxbkgY/5IdKV88m97R5YBi5oX/TOxw5l08eYehzje6 tHE+KfeLhrXsMtxyZpSu0GZ7NipKeSNWXNfJ+OtF1pOJnC2hppZA3Z2Nz5YJk9AvZYHR 642/D/rPKU1KqaHciRhYEi7gih4rowqCF/JAJLO62vIzTr17OTNPUZbAQvMxXv81Id5o jQYw13lWIuWN2SPS+HRRWqMmkUlsiCerp1Wfmjt4PcTySNXuh4CBlq4NSSH1SldxOv0l 6Ngbz1V4SaEBTVu/YyArLHctKPb2HzrwUZyeghflbPuGATCmHzEo9rX1tox+9MYr6TK9 0oWg== MIME-Version: 1.0 X-Received: by 10.152.21.38 with SMTP id s6mr98640lae.80.1386904275093; Thu, 12 Dec 2013 19:11:15 -0800 (PST) Received: by 10.114.59.164 with HTTP; Thu, 12 Dec 2013 19:11:15 -0800 (PST) In-Reply-To: <6895EAE0CA8DEE40B92D7CA88BB521F332BA573240@HQ1-EXCH02.corp.brocade.com> References: <6895EAE0CA8DEE40B92D7CA88BB521F332BA573240@HQ1-EXCH02.corp.brocade.com> Date: Fri, 13 Dec 2013 11:11:15 +0800 Message-ID: From: Jose Gavine Cueto To: Pashupati Kumar Content-Type: text/plain; charset=ISO-8859-1 X-Content-Filtered-By: Mailman/MimeDel 2.1.15 Cc: "dev@dpdk.org" Subject: Re: [dpdk-dev] kni vs. pmd 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: Fri, 13 Dec 2013 03:10:11 -0000 Hi Pashupati, Thanks for mentioning the extra copy. But I couldn't grasp much about "I look at KNI as more for control path operation and PMDs for data path" . Could you please give a simple example if you have time ? Thanks, Pepe On Fri, Dec 13, 2013 at 7:07 AM, Pashupati Kumar wrote: > > -----Original Message----- > > From: dev [mailto:dev-bounces@dpdk.org] On Behalf Of Jose Gavine Cueto > > Sent: Tuesday, December 10, 2013 3:16 PM > > To: dev@dpdk.org > > Subject: Re: [dpdk-dev] kni vs. pmd > > > > Additional question: > > > > Apart from the possible fact that kni performs zero-copy in the driver > layer, > > does this also apply on the sockets layer, or does the sockets > operations (+ > > sys calls) are not avoided ? This is assuming that the application uses > regular > > sockets to read/write to knis. > If you are going to use KNI, there is a copy involved from iovec to RTE > mbuf memory ( assuming you are going to use Ring library for communication > between DPDK application and KNI). I look at KNI as more for control path > operation and PMDs for data path. > > > > Cheers, > > Pepe > > > > > > On Wed, Dec 11, 2013 at 7:12 AM, Jose Gavine Cueto > > wrote: > > > > > Hi, > > > > > > Correct me if I'm wrong, but in a high-level perspective I see that > > > kni is providing an option for applications to use their regular > interfaces > > (e.g. > > > sockets) and abstracts the usage of pmds. > > > > > > If this is somehow correct, are there any differences with regard to > > > performance benefits that can be brought between directly using pmd > > > apis and kni ? > > > > > > I see that kni is easier to use, however at first (no code inspection) > > > look, it interfaces with the kernel which might have introduced some > > > overhead. > > > > > > Cheers, > > > Pepe > > > > > > > > > -- > > > To stop learning is like to stop loving. > > > > > > > > > > > -- > > To stop learning is like to stop loving. > > Thanks > Pash > -- To stop learning is like to stop loving.