From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mga11.intel.com (mga11.intel.com [192.55.52.93]) by dpdk.org (Postfix) with ESMTP id 148812BE1 for ; Fri, 30 Jun 2017 15:24:20 +0200 (CEST) Received: from orsmga002.jf.intel.com ([10.7.209.21]) by fmsmga102.fm.intel.com with ESMTP/TLS/DHE-RSA-AES256-GCM-SHA384; 30 Jun 2017 06:24:20 -0700 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.40,286,1496127600"; d="scan'208";a="105648522" Received: from irsmsx152.ger.corp.intel.com ([163.33.192.66]) by orsmga002.jf.intel.com with ESMTP; 30 Jun 2017 06:24:18 -0700 Received: from irsmsx102.ger.corp.intel.com ([169.254.2.211]) by IRSMSX152.ger.corp.intel.com ([169.254.6.83]) with mapi id 14.03.0319.002; Fri, 30 Jun 2017 14:24:18 +0100 From: "Van Haaren, Harry" To: Jerin Jacob CC: "Richardson, Bruce" , "dev@dpdk.org" , "thomas@monjalon.net" , "Wiles, Keith" Thread-Topic: Service lcores and Application lcores Thread-Index: AdLw4cih5pwlzbSuRKKmF+/821WngAABjH8AABrSm4AAC4OFsAAFe56AAAJhj0D///UUgP//7uxA Date: Fri, 30 Jun 2017 13:24:17 +0000 Message-ID: References: <20170629155707.GA15724@bricha3-MOBL3.ger.corp.intel.com> <20170630044508.GA3735@jerin> <20170630125147.GA4578@jerin> <20170630132054.GC4578@jerin> In-Reply-To: <20170630132054.GC4578@jerin> Accept-Language: en-US Content-Language: en-US X-MS-Has-Attach: X-MS-TNEF-Correlator: x-titus-metadata-40: eyJDYXRlZ29yeUxhYmVscyI6IiIsIk1ldGFkYXRhIjp7Im5zIjoiaHR0cDpcL1wvd3d3LnRpdHVzLmNvbVwvbnNcL0ludGVsMyIsImlkIjoiNjliNzM5ZTktY2IyZC00NzE1LWFjNGItN2EyNzFmNzZmZThkIiwicHJvcHMiOlt7Im4iOiJDVFBDbGFzc2lmaWNhdGlvbiIsInZhbHMiOlt7InZhbHVlIjoiQ1RQX0lDIn1dfV19LCJTdWJqZWN0TGFiZWxzIjpbXSwiVE1DVmVyc2lvbiI6IjE2LjUuOS4zIiwiVHJ1c3RlZExhYmVsSGFzaCI6Ilo1NDRnVzhmenByTEUxV2RcL3k1UlBNTUhaWGxaYnBGaE1WZ2RDZWhLQjhrPSJ9 x-ctpclassification: CTP_IC dlp-product: dlpe-windows dlp-version: 10.0.102.7 dlp-reaction: no-action x-originating-ip: [163.33.239.181] Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: quoted-printable MIME-Version: 1.0 Subject: Re: [dpdk-dev] Service lcores and Application lcores 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: Fri, 30 Jun 2017 13:24:21 -0000 > From: Jerin Jacob [mailto:jerin.jacob@caviumnetworks.com] > Sent: Friday, June 30, 2017 2:21 PM > To: Van Haaren, Harry > Cc: Richardson, Bruce ; dev@dpdk.org; thomas@= monjalon.net; > Wiles, Keith > Subject: Re: Service lcores and Application lcores >=20 > -----Original Message----- > > Date: Fri, 30 Jun 2017 13:08:26 +0000 > > From: "Van Haaren, Harry" > > To: Jerin Jacob > > CC: "Richardson, Bruce" , "dev@dpdk.org" > > , "thomas@monjalon.net" , "Wiles, > > Keith" > > Subject: RE: Service lcores and Application lcores > > > > > From: Jerin Jacob [mailto:jerin.jacob@caviumnetworks.com] > > > Sent: Friday, June 30, 2017 1:52 PM > > > To: Van Haaren, Harry > > > Cc: Richardson, Bruce ; dev@dpdk.org; tho= mas@monjalon.net; > > > Wiles, Keith > > > Subject: Re: Service lcores and Application lcores > > > > > > -----Original Message----- > > > > Date: Fri, 30 Jun 2017 10:00:18 +0000 > > > > From: "Van Haaren, Harry" > > > > To: Jerin Jacob , "Richardson, Bruc= e" > > > > > > > > CC: "dev@dpdk.org" , "thomas@monjalon.net" > > > > , "Wiles, Keith" > > > > Subject: RE: Service lcores and Application lcores > > > > > > > > > > I don't think providing a remote-launch API is actually beneficial.= Remote-launching > a > > > single service > > > > is equivalent to adding that lcore as a service-core, and mapping i= t to just that > single > > > service. > > > > The advantage of adding it as a service core, is future-proofing fo= r if more > services > > > need to be added > > > > to that core in future, and statistics of the service core infrastr= ucture. A > convenience > > > API could be > > > > provided to perform the core_add(), service_start(), enable_on_serv= ice() and > > > core_start() APIs in one. > > > > > > > > Also, the remote_launch API doesn't solve the original problem - wh= at if an > application > > > lcore wishes > > > > to run one iteration of a service "manually". The remote_launch sty= le API does not > solve > > > this problem. > > > > > > Agree with problem statement. But, remote_launch() operates on lcores= not on > > > not necessary on 1:1 mapped physical cores. > > > > > > By introducing "rte_service_iterate", We are creating a parallel infr= astructure to > > > run the service on non DPDK service lcores aka normal lcores. > > > Is this really required? Is there any real advantage for > > > application not use builtin service lcore infrastructure, rather than= iterating over > > > "rte_service_iterate" and run on normal lcores. If we really want to = mux > > > a physical core to N lcore, EAL already provides that in the form of = threads. > > > > > > I think, providing too many parallel options for the same use case ma= y be > > > a overkill. > > > > > > Just my 2c. > > > > > > The use-case that the rte_service_iterate() caters for is one where the= application > > wishes to run a service on an "ordinary app lcore", together with an ap= plication > workload. > > > > For example, the eventdev-scheduler and one worker can be run on the sa= me lcore. If the > schedule() running thread *must* be a service lcore, we would not be able= to also use that > lcore as an application worker core. > > > > That was my motivation for adding this API, I do agree with you above; = it is a second > "parallel" method to run a service. I think there's enough value in enabl= ing the use-case > as per example above to add it. > > > > > > Do you see enough value in the use-case above to add the API? >=20 > The above use case can be realized like --lcores=3D'(0-1)@1'(Two lcore on > an physical core). I believe, application writers never want to write a > code based on specific number of cores available in the system. If they > do then they will be stuck on running on another environment and too > many combination to address. Good point. > For me it complicates service lcore usage. But someone think, it will use= ful then > I don't have strong objection. We can easily add APIs later - and removing them isn't so easy. +1 from me = leave it out for now, and we can see about adding it for 17.11 if the need = arises. Thanks for your input, I'll spin a v3 without the rte_service_iterate() fun= ction, and that should be it then! =20