From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: <mleitner@redhat.com> Received: from mx1.redhat.com (mx1.redhat.com [209.132.183.28]) by dpdk.org (Postfix) with ESMTP id 6CCE11B3F7 for <dev@dpdk.org>; Mon, 5 Feb 2018 16:29:45 +0100 (CET) Received: from smtp.corp.redhat.com (int-mx05.intmail.prod.int.phx2.redhat.com [10.5.11.15]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mx1.redhat.com (Postfix) with ESMTPS id 77A3E83F46; Mon, 5 Feb 2018 15:29:44 +0000 (UTC) Received: from localhost.localdomain (ovpn-116-10.gru2.redhat.com [10.97.116.10]) by smtp.corp.redhat.com (Postfix) with ESMTPS id E2FDB5EDE6; Mon, 5 Feb 2018 15:29:43 +0000 (UTC) Received: by localhost.localdomain (Postfix, from userid 1000) id 4DA16181078; Mon, 5 Feb 2018 13:29:42 -0200 (-02) Date: Mon, 5 Feb 2018 13:29:42 -0200 From: Marcelo Ricardo Leitner <mleitner@redhat.com> To: Adrien Mazarguil <adrien.mazarguil@6wind.com> Cc: Thomas Monjalon <thomas@monjalon.net>, "Van Haaren, Harry" <harry.van.haaren@intel.com>, "dev@dpdk.org" <dev@dpdk.org>, Shahaf Shuler <shahafs@mellanox.com>, Nelio Laranjeiro <nelio.laranjeiro@6wind.com> Message-ID: <20180205152942.GH27676@localhost.localdomain> References: <20180202144736.8239-1-adrien.mazarguil@6wind.com> <20180205125806.GE27676@localhost.localdomain> <20180205134446.GG4256@6wind.com> <1992025.8JADqR79Gx@xps> <20180205143734.GG27676@localhost.localdomain> <20180205145917.GJ4256@6wind.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20180205145917.GJ4256@6wind.com> User-Agent: Mutt/1.9.1 (2017-09-22) X-Scanned-By: MIMEDefang 2.79 on 10.5.11.15 X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.5.16 (mx1.redhat.com [10.5.110.27]); Mon, 05 Feb 2018 15:29:44 +0000 (UTC) Subject: Re: [dpdk-dev] [PATCH v2 3/4] net/mlx: version rdma-core glue libraries X-BeenThere: dev@dpdk.org X-Mailman-Version: 2.1.15 Precedence: list List-Id: DPDK patches and discussions <dev.dpdk.org> List-Unsubscribe: <https://dpdk.org/ml/options/dev>, <mailto:dev-request@dpdk.org?subject=unsubscribe> List-Archive: <http://dpdk.org/ml/archives/dev/> List-Post: <mailto:dev@dpdk.org> List-Help: <mailto:dev-request@dpdk.org?subject=help> List-Subscribe: <https://dpdk.org/ml/listinfo/dev>, <mailto:dev-request@dpdk.org?subject=subscribe> X-List-Received-Date: Mon, 05 Feb 2018 15:29:45 -0000 On Mon, Feb 05, 2018 at 03:59:18PM +0100, Adrien Mazarguil wrote: > On Mon, Feb 05, 2018 at 12:37:34PM -0200, Marcelo Ricardo Leitner wrote: > > On Mon, Feb 05, 2018 at 03:16:21PM +0100, Thomas Monjalon wrote: > > > 05/02/2018 14:44, Adrien Mazarguil: > > > > On Mon, Feb 05, 2018 at 10:58:06AM -0200, Marcelo Ricardo Leitner wrote: > > > > > On Mon, Feb 05, 2018 at 12:24:23PM +0000, Van Haaren, Harry wrote: > > > > > > > From: dev [mailto:dev-bounces@dpdk.org] On Behalf Of Marcelo Ricardo Leitner > > > > > > > Sent: Monday, February 5, 2018 12:14 PM > > > > > > > To: Adrien Mazarguil <adrien.mazarguil@6wind.com> > > > > > > > Cc: Thomas Monjalon <thomas@monjalon.net>; dev@dpdk.org; Shahaf Shuler > > > > > > > <shahafs@mellanox.com>; Nelio Laranjeiro <nelio.laranjeiro@6wind.com> > > > > > > > Subject: Re: [dpdk-dev] [PATCH v2 3/4] net/mlx: version rdma-core glue > > > > > > > libraries > > > > > > > > > > > > > > On Mon, Feb 05, 2018 at 12:24:02PM +0100, Adrien Mazarguil wrote: > > > > > > > > On Sun, Feb 04, 2018 at 03:29:38PM +0100, Thomas Monjalon wrote: > > > > > > > > > 02/02/2018 17:46, Adrien Mazarguil: > > > > > > > > > > --- a/drivers/net/mlx4/Makefile > > > > > > > > > > +++ b/drivers/net/mlx4/Makefile > > > > > > > > > > @@ -33,7 +33,9 @@ include $(RTE_SDK)/mk/rte.vars.mk > > > > > > > > > > > > > > > > > > > > # Library name. > > > > > > > > > > LIB = librte_pmd_mlx4.a > > > > > > > > > > -LIB_GLUE = librte_pmd_mlx4_glue.so > > > > > > > > > > +LIB_GLUE = $(LIB_GLUE_BASE).$(LIB_GLUE_VERSION) > > > > > > > > > > +LIB_GLUE_BASE = librte_pmd_mlx4_glue.so > > > > > > > > > > +LIB_GLUE_VERSION = 18.02.1 > > > > > > > > > > > > > > > > > > You should use the version number of the release, i.e. 18.02.0 > > > > > > > > > Ideally, you should retrieve it from rte_version.h. > > > > > > > > > > > > > > > > Keep in mind this only needs to be updated when the glue API gets > > > > > > > modified, > > > > > > > > and this "18.02.1" string may remain unmodified for subsequent DPDK > > > > > > > > releases, probably as long as the PMD doesn't use any new rdma-core calls. > > > > > > > > > > > > > > > > We've already backported this patch to 17.02 and 17.11, both requiring > > > > > > > > different sets of Verbs calls and thus a different version, hence the > > > > > > > added > > > > > > > > "18.02" as a starting point. The last digit may have to be modified > > > > > > > possibly > > > > > > > > several times between official DPDK releases while work is being done on > > > > > > > the > > > > > > > > PMD (i.e. per commit). > > > > > > > > > > > > > > > > In short it's not meant to follow DPDK's public versioning scheme. If you > > > > > > > > really think it should, doing so will make things more complex in the > > > > > > > > Makefile, which will have to parse rte_version.h. What's your opinion? > > > > > > > > > > > > > > What about appending date +%s output to it? It would be stricter and > > > > > > > automated. > > > > > > > > > > > > Adding current timestamp or date into a build breaks reproducibility of builds, so is > > > > > > generally not recommended. > > > > > > > > > > Then the sha1sum of mlx4_glue.h. > > > > > With this the size check I mentioned on the other patch would become > > > > > redundant and unnecessary. > > > > > > > > Using a strong hash algorithm to version a library/symbol, while possible, > > > > seems a bit overkill and results in ugliness: > > > > > > > > librte_pmd_mlx4.so.c4ca4eaf2fe975ead83453458f4f56db49e724f3 > > > > Ugh yes, but it wouldn't need to be that visible. A pointer on > > mlx*_glue and a define on PMD would be enough already. As in, an > > extended check to the versioning. > > I thought you suggested this as a replacement. I'm not sure we need or want > to go this far. The current string comparison is really not worse than > standard symbol versioning, which doesn't check symbol properties besides > whether they are functions or other objects. We could have used C++ with > automatically mangled symbol names for that, however that again would make > things way more complex than necessary. > > > > > Using a weak one like CRC32 for a shorter name poses a risk of > > > > collision. Moreover the next time someone decides to update all version > > > > notices or modify a comment will impact that hash. We'd need to isolate the > > > > symbol definition itself, ignore parameter names in function prototypes and > > > > only then we may get a somewhat meaningful hash describing a given ABI. > > > > That's what I meant with stricter. Yes it would catch such > > situations, but you tell me on how much we want to protect/restrict > > here. Do you see a reason for building only the dpdk/pmd side and not > > the glue library at a time? > > No, they're always built together. We're only adding this versioning to > avoid issues when users somehow end up with several DPDK versions installed > on their system, or with leftovers of previous releases lying around. That's > all we need to solve here. dlopen()'ing the proper file takes care of that, > the symbol version number check afterward is performed just in case. Interesting. These leftovers probably wouldn't be there if it wasn't versioned in the first place. :-) > > > > > Given the added complexity, is there really a problem with simple version > > > > numbers we increment every time something gets modified? (Note this is > > > > already how our .map files work, they're not generated automatically) > > > > > > Our map files show the major version where a symbol was introduced. > > > It is simple because no symbol can be introduced in a minor version. > > > > > > > How about keeping things as is? > > > > I don't really see the need of unique filenames. The next patch is > > already leveraging RTE_EAL_PMD_PATH, which if versioned should be > > enough for this, no? > > As you said, "if" versioned. As an undocumented empty string by default, > there's no way to be sure. Leaving the PMD version its internal but > (unfortunately) exposed bits will certainly prevent mistakes. > > > > You are using 18.02.1 while it is introduced in 18.02.0. > > > If you don't want to correlate the .so version number with DPDK version > > > number, maybe that 1, 2, 3 would be a simpler choice (less confusing). > > > > +1 > > Then are you fine with the "18.02.0" suffix? Not really, sorry. It was more for the "1, 2, 3" sequence or tying it to dpdk version. With the latest replies, I don't think the reasoning is enough to justify these extra checks, but I won't oppose to including it. Marcelo