From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail.droids-corp.org (zoll.droids-corp.org [94.23.50.67]) by dpdk.org (Postfix) with ESMTP id 588BB2C01 for ; Tue, 19 Jul 2016 17:04:17 +0200 (CEST) Received: from alille-653-1-293-182.w90-1.abo.wanadoo.fr ([90.1.53.182] helo=[192.168.1.13]) by mail.droids-corp.org with esmtpsa (TLS1.2:ECDHE_RSA_AES_128_GCM_SHA256:128) (Exim 4.84_2) (envelope-from ) id 1bPWbc-0004rQ-Jm; Tue, 19 Jul 2016 17:06:49 +0200 To: Bruce Richardson References: <1468936875-1652-1-git-send-email-olivier.matz@6wind.com> <20160719144018.GA10912@bricha3-MOBL3> Cc: dev@dpdk.org, jerin.jacob@caviumnetworks.com, thomas.monjalon@6wind.com From: Olivier Matz Message-ID: Date: Tue, 19 Jul 2016 17:04:01 +0200 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:45.0) Gecko/20100101 Icedove/45.1.0 MIME-Version: 1.0 In-Reply-To: <20160719144018.GA10912@bricha3-MOBL3> Content-Type: text/plain; charset=windows-1252 Content-Transfer-Encoding: 7bit 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 15:04:17 -0000 Hi Bruce, On 07/19/2016 04:40 PM, Bruce Richardson wrote: > 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? Yes, you are right. What about the following text? ABI changes are planned for 16.11 in the ``rte_mbuf`` structure: some fields may 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 ``port`` field may also be removed at the same occasion. Thanks, Olivier