From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: <bruce.richardson@intel.com> Received: from mga03.intel.com (mga03.intel.com [143.182.124.21]) by dpdk.org (Postfix) with ESMTP id 9A58A592F for <dev@dpdk.org>; Tue, 20 May 2014 13:02:46 +0200 (CEST) Received: from azsmga001.ch.intel.com ([10.2.17.19]) by azsmga101.ch.intel.com with ESMTP; 20 May 2014 04:02:54 -0700 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="4.98,873,1392192000"; d="scan'208";a="434441928" Received: from irsmsx102.ger.corp.intel.com ([163.33.3.155]) by azsmga001.ch.intel.com with ESMTP; 20 May 2014 04:02:53 -0700 Received: from irsmsx105.ger.corp.intel.com (163.33.3.28) by IRSMSX102.ger.corp.intel.com (163.33.3.155) with Microsoft SMTP Server (TLS) id 14.3.123.3; Tue, 20 May 2014 12:02:15 +0100 Received: from irsmsx103.ger.corp.intel.com ([169.254.3.183]) by IRSMSX105.ger.corp.intel.com ([169.254.7.70]) with mapi id 14.03.0123.003; Tue, 20 May 2014 12:02:15 +0100 From: "Richardson, Bruce" <bruce.richardson@intel.com> To: Neil Horman <nhorman@tuxdriver.com> Thread-Topic: [dpdk-dev] [PATCH 0/4] New library: rte_distributor Thread-Index: AQHPdBJ9PtpJ6FkU3k+uqZChiy9wXJtJNnGAgAAUGmA= Date: Tue, 20 May 2014 11:02:15 +0000 Message-ID: <59AF69C657FD0841A61C55336867B5B01AA1BCF2@IRSMSX103.ger.corp.intel.com> References: <1400580057-30155-1-git-send-email-bruce.richardson@intel.com> <20140520103845.GA6648@hmsreliant.think-freely.org> In-Reply-To: <20140520103845.GA6648@hmsreliant.think-freely.org> Accept-Language: en-GB, en-US Content-Language: en-US X-MS-Has-Attach: X-MS-TNEF-Correlator: x-originating-ip: [163.33.239.180] Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: quoted-printable MIME-Version: 1.0 Cc: "dev@dpdk.org" <dev@dpdk.org> Subject: Re: [dpdk-dev] [PATCH 0/4] New library: rte_distributor 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: Tue, 20 May 2014 11:02:47 -0000 > -----Original Message----- > From: Neil Horman [mailto:nhorman@tuxdriver.com] > Sent: Tuesday, May 20, 2014 11:39 AM > To: Richardson, Bruce > Cc: dev@dpdk.org > Subject: Re: [dpdk-dev] [PATCH 0/4] New library: rte_distributor >=20 > > > This sounds an awful lot like the team and bonding drivers. Why implemen= t this > as a separate application accessible api, rather than a stacked PMD? If = you do > the latter then existing applications could concievably change their > configurations to use this technology and gain the benefit of load distri= bution > without having to alter the application to use a new api. >=20 I'm not sure I see the similarity with the bonded driver, which merges mult= iple ports into a single logical port, i.e. you pull packets from a single = source which is actually pull packets from possibly multiple sources behind= the scenes, whereas this takes packets from an unknown source and distribu= tes them among a set of workers a single packet at a time. (While handling = single packets is slower than handling packet bursts, it is something that = is sometimes needed to support existing code which may not be written to wo= rk with packet bursts.)=20 The load balancing is also more dynamic than that done by existing mechanis= ms, since no calculation is done on the packets or the packet metadata to a= ssign a packet to a worker - instead if a particular flow tag is not in-fli= ght with a worker, the next packet with that tag goes to the next available= worker. In this way, the library also takes care of ensuring that packets = from a single flow are maintained in order, and provides a mechanism to hav= e the packets passed back to the distributor thread when done, for further = processing there, e.g. rescheduling a second time, or other actions.=20 While in certain circumstances an ethdev rx/tx API could be used (and it is= something we have thought about and may well add to this library in future= ), there are certain requirements that cannot be met by just making this a = stacked ethdev/PMD: * not all packets come from an rx_burst call on another PMD, especially whe= re the tags on the packets need to be computed by software * the rx_burst API call provides no way to pass back packets to the source = when finished.