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 4DA218064 for ; Mon, 22 Dec 2014 10:46:26 +0100 (CET) Received: from orsmga002.jf.intel.com ([10.7.209.21]) by fmsmga102.fm.intel.com with ESMTP; 22 Dec 2014 01:46:24 -0800 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.07,622,1413270000"; d="scan'208";a="658353214" Received: from bricha3-mobl3.ger.corp.intel.com ([10.243.20.25]) by orsmga002.jf.intel.com with SMTP; 22 Dec 2014 01:46:16 -0800 Received: by (sSMTP sendmail emulation); Mon, 22 Dec 2014 09:46:03 +0025 Date: Mon, 22 Dec 2014 09:46:03 +0000 From: Bruce Richardson To: "Liang, Cunming" Message-ID: <20141222094603.GA1768@bricha3-MOBL3> References: <1418263490-21088-1-git-send-email-cunming.liang@intel.com> <7C4248CAE043B144B1CD242D275626532FE15298@IRSMSX104.ger.corp.intel.com> <7C4248CAE043B144B1CD242D275626532FE232BA@IRSMSX104.ger.corp.intel.com> <7C4248CAE043B144B1CD242D275626532FE27C3B@IRSMSX104.ger.corp.intel.com> <20141219100342.GA3848@bricha3-MOBL3> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: Organization: Intel Shannon Ltd. User-Agent: Mutt/1.5.23 (2014-03-12) Cc: "dev@dpdk.org" Subject: Re: [dpdk-dev] [RFC PATCH 0/7] support multi-phtread per lcore 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: Mon, 22 Dec 2014 09:46:26 -0000 On Mon, Dec 22, 2014 at 01:51:27AM +0000, Liang, Cunming wrote: > ... > > I'm conflicted on this one. However, I think far more applications would be > > broken > > to start having to use thread_id in place of an lcore_id than would be broken > > by having the lcore_id no longer actually correspond to a core. > > I'm actually struggling to come up with a large number of scenarios where it's > > important to an app to determine the cpu it's running on, compared to the large > > number of cases where you need to have a data-structure per thread. In DPDK > > libs > > alone, you see this assumption that lcore_id == thread_id a large number of > > times. > > > > Despite the slight logical inconsistency, I think it's better to avoid introducing > > a thread-id and continue having lcore_id representing a unique thread. > > > > /Bruce > > Ok, I understand it. > I list the implicit meaning if using lcore_id representing the unique thread. > 1). When lcore_id less than RTE_MAX_LCORE, it still represents the logical core id. > 2). When lcore_id large equal than RTE_MAX_LCORE, it represents an unique id for thread. > 3). Most of APIs(except rte_lcore_id()) in rte_lcore.h suggest to be used only in CASE 1) > 4). rte_lcore_id() can be used in CASE 2), but the return value no matter represent a logical core id. > > If most of us feel it's acceptable, I'll prepare for the RFC v2 base on this conclusion. > > /Cunming Sorry, I don't like that suggestion either, as having lcore_id values greater than RTE_MAX_LCORE is terrible, as how will people know how to dimension arrays to be indexes by lcore id? Given the choice, if we are not going to just use lcore_id as a generic thread id, which is always between 0 and RTE_MAX_LCORE we can look to define a new thread_id variable to hold that. However, it should have a bounded range. >>From an ease-of-porting perspective, I still think that the simplest option is to use the existing lcore_id and accept the fact that it's now a thread id rather than an actual physical lcore. Question is, is would that cause us lots of issues in the future? /Bruce