From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mails.dpdk.org (mails.dpdk.org [217.70.189.124]) by inbox.dpdk.org (Postfix) with ESMTP id BCB23A055B; Tue, 16 Feb 2021 18:31:09 +0100 (CET) Received: from [217.70.189.124] (localhost [127.0.0.1]) by mails.dpdk.org (Postfix) with ESMTP id 5CC1B16076E; Tue, 16 Feb 2021 18:31:09 +0100 (CET) Received: from mga14.intel.com (mga14.intel.com [192.55.52.115]) by mails.dpdk.org (Postfix) with ESMTP id 2C89A40690 for ; Tue, 16 Feb 2021 18:31:07 +0100 (CET) IronPort-SDR: 5k5e42tiNJBPZZHHV6fwgcn4JgHjHtF85hTF28Y188yU+IsH8eFOvoORH3b+WJ744ORdMgq/B1 gWiyixcgvivA== X-IronPort-AV: E=McAfee;i="6000,8403,9897"; a="182179122" X-IronPort-AV: E=Sophos;i="5.81,184,1610438400"; d="scan'208";a="182179122" Received: from orsmga001.jf.intel.com ([10.7.209.18]) by fmsmga103.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 16 Feb 2021 09:31:04 -0800 IronPort-SDR: Z3MdVlldCMZNA6GX7Uf3cnPEAs+B0gSiDonxrqiIuPhhhc0GA846fFMcFtSo++QqblJM5oVdXL ZbB9l/OX3Jbw== X-IronPort-AV: E=Sophos;i="5.81,184,1610438400"; d="scan'208";a="439005188" Received: from bricha3-mobl.ger.corp.intel.com ([10.252.4.41]) by orsmga001-auth.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-SHA; 16 Feb 2021 09:31:02 -0800 Date: Tue, 16 Feb 2021 17:30:57 +0000 From: Bruce Richardson To: "Van Haaren, Harry" Cc: "Burakov, Anatoly" , "dev@dpdk.org" Message-ID: <20210216173057.GE136@bricha3-MOBL.ger.corp.intel.com> References: <20210216094300.27889-1-bruce.richardson@intel.com> <313c223f-bf1c-9307-75f8-0a0c1da7fd21@intel.com> <20210216104652.GB136@bricha3-MOBL.ger.corp.intel.com> <42706d4c-f8de-55c5-1161-b1e54c77599e@intel.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: Subject: Re: [dpdk-dev] [PATCH] eal: support using 0 as coremask for no-affinitization X-BeenThere: dev@dpdk.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: DPDK patches and discussions List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: dev-bounces@dpdk.org Sender: "dev" On Tue, Feb 16, 2021 at 05:22:25PM +0000, Van Haaren, Harry wrote: > > -----Original Message----- > > From: Burakov, Anatoly > > Sent: Tuesday, February 16, 2021 10:53 AM > > To: Richardson, Bruce ; Van Haaren, Harry > > > > Cc: dev@dpdk.org > > Subject: Re: [dpdk-dev] [PATCH] eal: support using 0 as coremask for no- > > affinitization > > > > On 16-Feb-21 10:46 AM, Bruce Richardson wrote: > > > On Tue, Feb 16, 2021 at 10:36:13AM +0000, Burakov, Anatoly wrote: > > >> On 16-Feb-21 9:43 AM, Bruce Richardson wrote: > > >>> Allow the user to specify that they don't want any core pinning from DPDK > > >>> by passing in the coremask of 0. > > >>> --- > > >> > > >> I haven't checked what happens yet, but down the line we also set affinity > > >> for service cores as well as interrupt thread. what would be the semantics > > >> of those in this particular case? do we want the same ability for service > > >> cores (i.e. pick a non-affinitized core)? And where does interrupt thread > > >> affinitize in this case (presumably, nowhere too)? > > >> > > > I have not checked the service core setup, because a) I forgot about them > > > and b) I'm not sure how their affinity rules work with respect to the main > > > lcore mask. On the other hand I did check out that the lcore mask for all > > > non-pinned threads, or control threads, is the full set of bits as > > > expected. > > > > > > /Bruce > > > > > > > +Harry, > > > > I believe service core mask must not overlap with lcore masks, so > > presumably using 0 as lcore mask would make it so that any service core > > mask will be valid (which is presumably what we want?). > > Services cores -S list or -s *must* overlap with the RTE lcores, EAL > then"steals" the service cores from the application lcores, code that implements here: > http://git.dpdk.org/dpdk-stable/tree/lib/librte_eal/common/eal_common_options.c?h=20.11#n657 > > > Should service cores also have a "just pick a core" parameter? > > I'm not sure, depends on what the bigger goal is here. > Assuming we're enabling this for ROLE_RTE threads, then > it would seem to me that ROLE_SERVICE and control threads > would require similar treatment? > Control threads are affinitised to all cores not in the coremask, which means in this case that they can run anywhere on the system the OS chooses. In case of service cores, it would seem that using service cores with an empty coremask is just not compatible. I would assume that this incompatibility already exists when one has a coremask with only one core already in it. /Bruce