From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mx1.redhat.com (mx1.redhat.com [209.132.183.28]) by dpdk.org (Postfix) with ESMTP id CF103B47E for ; Fri, 13 Feb 2015 11:33:22 +0100 (CET) Received: from int-mx13.intmail.prod.int.phx2.redhat.com (int-mx13.intmail.prod.int.phx2.redhat.com [10.5.11.26]) by mx1.redhat.com (8.14.4/8.14.4) with ESMTP id t1DAXK1K006485 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-GCM-SHA384 bits=256 verify=FAIL); Fri, 13 Feb 2015 05:33:20 -0500 Received: from localhost.localdomain (vpn1-7-60.ams2.redhat.com [10.36.7.60]) by int-mx13.intmail.prod.int.phx2.redhat.com (8.14.4/8.14.4) with ESMTP id t1DAXIsD015730; Fri, 13 Feb 2015 05:33:19 -0500 Message-ID: <54DDD2EE.7070505@redhat.com> Date: Fri, 13 Feb 2015 12:33:18 +0200 From: Panu Matilainen User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:31.0) Gecko/20100101 Thunderbird/31.4.0 MIME-Version: 1.0 To: Thomas Monjalon References: <6ca22ee1257e34ee2b89f2fb354d6c382b8f3e29.1423644785.git.pmatilai@redhat.com> <3129786.dHlkKq5arh@xps13> <54DDA759.3060908@redhat.com> <12066921.2HzVPH8BW6@xps13> In-Reply-To: <12066921.2HzVPH8BW6@xps13> Content-Type: text/plain; charset=utf-8; format=flowed Content-Transfer-Encoding: 7bit X-Scanned-By: MIMEDefang 2.68 on 10.5.11.26 Cc: dev@dpdk.org Subject: Re: [dpdk-dev] [PATCH] mk: fix missing link of librte_vhost in shared, non-combined config 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: Fri, 13 Feb 2015 10:33:23 -0000 On 02/13/2015 11:28 AM, Thomas Monjalon wrote: > 2015-02-13 09:27, Panu Matilainen: >> On 02/12/2015 05:44 PM, Thomas Monjalon wrote: >>> 2015-02-11 12:31, Gonzalez Monroy, Sergio: >>>> From: Panu Matilainen [mailto:pmatilai@redhat.com] >>>>> On 02/11/2015 12:51 PM, Gonzalez Monroy, Sergio wrote: >>>>>> I think that vhost is being linked in the wrong place (plugins section). >>>>>> The plugins only get linked when building static libraries. >>>>>> I think the patch should also remove vhost from the plugins section. >>>>> >>>>> Right, so vhost isn't a pluggable driver in the sense that pmds are. I wont >>>>> claim to be familiar with all this virt-related puzzle pieces :) I'll send an >>>>> updated patch, I was just looking to fix build in my particular config and >>>>> ignored the rest. >>>>> >>>>> On a related note, shouldn't librte_pmd_bond and librte_pmd_xenvirt be >>>>> included in the plugins section along with all the other pmds? >>>>> >>>> Hi Panu, >>>> >>>> Good question :) >>>> >>>> I did wonder the same thing not long ago. >>>> >>>> I think the reason is that (someone may correct me if I'm wrong) there >>>> are specific unit tests for those pmds (testing extra API) that require >>>> them to always be linked against. >>> >>> A library is considered as a plugin if there is no public API and it >>> registers itself. That's the case of normal PMD. >>> But bonding and Xen have some library parts with public API. >>> It has been discussed and agreed for bonding but I'm not aware of the Xen case. >> >> Fair enough, thanks for the explanation. >> >> Just wondering about versioning of these things - currently all the PMDs >> are versioned as well, which is slightly at odds with their expected >> usage, dlopen()'ed items usually are not versioned because it makes the >> files moving targets. But if a plugin can be an library too then it >> clearly needs to be versioned as well. > > Not sure to understand your considerations. > Plugins must be versioned because there can be some incompatibilities > like mbuf rework. Plugins are version-dependent obviously, but the issue is somewhat different from library versioning. Plugins are generally consumers of the versioned ABIs, whereas libraries are the providers. > >> I'm just thinking of typical packaging where the unversioned *.so >> symlinks are in a -devel subpackage and the versioned libraries are in >> the main runtime package. Plugins should be loadable by a stable >> unversioned name always, for libraries the linker handles it behind the >> scenes. So in packaging these things, plugin *.so links need to be >> handled differently (placed into the main package) from others. Not >> rocket science to filter by 'pmd' in the name, but a new twist anyway >> and easy to get wrong. >> >> One possibility to make it all more obvious might be having a separate >> directory for plugins, the mixed case ccould be handled by symlinks. > > I think I don't understand which use case you are trying to solve. > Its a usability/documentation issue more than a technical one. If plugin DSO's are versioned (like they currently are), then loading them via eg -d becomes cumbersome since you need to hunt down and provide the versioned name, eg "testpmd -d librte_pmd_pcap.so.1 [...]" Like said above, it can be worked around by leaving the unversioned symlinks in place for plugins in runtime (library) packages, but that sort of voids the point of versioning. One possibility would be introducing a per-version plugin directory that would be used as the default path for dlopen() unless an absolute path is used. - Panu -