From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mga09.intel.com (mga09.intel.com [134.134.136.24]) by dpdk.org (Postfix) with ESMTP id 5EB36379B for ; Tue, 19 Jul 2016 16:40:28 +0200 (CEST) Received: from fmsmga004.fm.intel.com ([10.253.24.48]) by orsmga102.jf.intel.com with ESMTP; 19 Jul 2016 07:40:26 -0700 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.28,389,1464678000"; d="scan'208";a="141903205" Received: from bricha3-mobl3.ger.corp.intel.com ([10.237.221.100]) by fmsmga004.fm.intel.com with SMTP; 19 Jul 2016 07:40:20 -0700 Received: by (sSMTP sendmail emulation); Tue, 19 Jul 2016 15:40:19 +0025 Date: Tue, 19 Jul 2016 15:40:18 +0100 From: Bruce Richardson To: Olivier Matz Cc: dev@dpdk.org, jerin.jacob@caviumnetworks.com, thomas.monjalon@6wind.com Message-ID: <20160719144018.GA10912@bricha3-MOBL3> References: <1468936875-1652-1-git-send-email-olivier.matz@6wind.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1468936875-1652-1-git-send-email-olivier.matz@6wind.com> Organization: Intel Research and =?iso-8859-1?Q?De=ACvel?= =?iso-8859-1?Q?opment?= Ireland Ltd. User-Agent: Mutt/1.5.23 (2014-03-12) Subject: Re: [dpdk-dev] [PATCH] doc: announce ABI change for mbuf structure 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: Tue, 19 Jul 2016 14:40:29 -0000 On Tue, Jul 19, 2016 at 04:01:15PM +0200, Olivier Matz wrote: > For 16.11, the mbuf structure will be modified implying ABI breakage. > Some discussions already took place here: > http://www.dpdk.org/dev/patchwork/patch/12878/ > > Signed-off-by: Olivier Matz > --- > doc/guides/rel_notes/deprecation.rst | 6 ++++++ > 1 file changed, 6 insertions(+) > > diff --git a/doc/guides/rel_notes/deprecation.rst b/doc/guides/rel_notes/deprecation.rst > index f502f86..2245bc2 100644 > --- a/doc/guides/rel_notes/deprecation.rst > +++ b/doc/guides/rel_notes/deprecation.rst > @@ -41,3 +41,9 @@ Deprecation Notices > * The mempool functions for single/multi producer/consumer are deprecated and > will be removed in 16.11. > It is replaced by rte_mempool_generic_get/put functions. > + > +* ABI changes are planned for 16.11 in the ``rte_mbuf`` structure: some > + fields will be reordered to facilitate the writing of ``data_off``, > + ``refcnt``, and ``nb_segs`` in one operation. Indeed, some platforms > + have an overhead if the store address is not naturally aligned. The > + useless ``port`` field will also be removed at the same occasion. > -- Have we fully bottomed out on the mbuf changes. I'm not sure that once patches start getting considered for merge, new opinions may come forward. For instance, is the "port" field really "useless"? Would it not be better to put in a less specific deprecation notice? What happens if this notice goes in and the final changes are different from those called out here? /Bruce