From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mga02.intel.com (mga02.intel.com [134.134.136.20]) by dpdk.org (Postfix) with ESMTP id 09C9B5A9A for ; Thu, 12 Feb 2015 10:17:42 +0100 (CET) Received: from orsmga003.jf.intel.com ([10.7.209.27]) by orsmga101.jf.intel.com with ESMTP; 12 Feb 2015 01:17:41 -0800 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.09,564,1418112000"; d="scan'208";a="526459546" Received: from smonroyx-mobl.ger.corp.intel.com (HELO [10.237.221.21]) ([10.237.221.21]) by orsmga003.jf.intel.com with ESMTP; 12 Feb 2015 01:09:28 -0800 Message-ID: <54DC6FB3.8020608@intel.com> Date: Thu, 12 Feb 2015 09:17:39 +0000 From: "Gonzalez Monroy, Sergio" User-Agent: Mozilla/5.0 (Windows NT 6.3; WOW64; rv:31.0) Gecko/20100101 Thunderbird/31.4.0 MIME-Version: 1.0 To: Neil Horman References: <1422544811-26385-1-git-send-email-sergio.gonzalez.monroy@intel.com> <20150129163859.GE1999@hmsreliant.think-freely.org> <91383E96CE459D47BCE92EFBF5CE73B004F43D9B@IRSMSX108.ger.corp.intel.com> <20150129194539.GG1999@hmsreliant.think-freely.org> <91383E96CE459D47BCE92EFBF5CE73B004F453D7@IRSMSX108.ger.corp.intel.com> <20150130140507.GA2664@hmsreliant.think-freely.org> <91383E96CE459D47BCE92EFBF5CE73B004F45534@IRSMSX108.ger.corp.intel.com> <20150130181249.GC2664@hmsreliant.think-freely.org> <91383E96CE459D47BCE92EFBF5CE73B004F4AB9B@IRSMSX108.ger.corp.intel.com> <20150212054105.GC5504@neilslaptop.think-freely.org> In-Reply-To: <20150212054105.GC5504@neilslaptop.think-freely.org> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit Cc: "dev@dpdk.org" Subject: Re: [dpdk-dev] [PATCH 0/8] Improve build process 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: Thu, 12 Feb 2015 09:17:43 -0000 On 12/02/2015 05:41, Neil Horman wrote: > On Wed, Feb 11, 2015 at 11:11:13AM +0000, Gonzalez Monroy, Sergio wrote: >>> From: Neil Horman [mailto:nhorman@tuxdriver.com] >>> Sent: Friday, January 30, 2015 6:13 PM >>> To: Gonzalez Monroy, Sergio >>> Cc: Thomas Monjalon; dev@dpdk.org >>> Subject: Re: [dpdk-dev] [PATCH 0/8] Improve build process >>> >>> On Fri, Jan 30, 2015 at 05:38:49PM +0000, Gonzalez Monroy, Sergio wrote: >> [snip] >> >>>> So would it be reasonable to add DT_NEEDED entries to all DPDK libraries >>> but EAL? >>>> If I understood what you were saying right, we could enforce the >>>> 'dependency' in the linker script with something like this: >>>> $ cat librte_eal.so >>>> INPUT( librte_eal.so.1 -lrte_mempool -lrte_malloc) We could have such >>>> linker script for librte_eal.so instead of the soft link once >>>> versioning is in place. >>>> >>> Correct. >>> >>>> Things that would be missing versus the proposed patch: >>>> - As I have mention in previous post, ldd info for EAL library would not >>> reflect >>>> its dependency to other DPDK libs. >>> librte_eal.so would no show those dependencies, as far as I know (though I >>> haven't explicitly checked). The subordunate libraries included in the input >>> line, may or may not show dependencies among themselves, depending on >>> your build setup (and the use of --no-as-needed and -l when linking the >>> individual .so libraries. >>> >>>> - I was enforcing resolving all references when building the libraries (-z >>> defs), so >>>> we either remove it altogether or skip eal. >>> I think thats correct, yes. >>> >>>> - All apps would show DT_NEEDED entries for a set of DPDK libraries that >>>> in most cases are required (eal, mempool, malloc, mbuf, ring VS >>>> dpdk_core) >>>> >>> I think apps linked to libdpdk_core would have DT_NEEDED entries for >>> libdpdk_core, not the subordonate libraries (though check me on that to be >>> sure). >>> >> Just checked on this and they do link against the subordinate libraries, although >> It does not really matter as we are dropping the 'core' library approach anyway. >> > ok, understood. > >>>> I think that the linker script approach is reasonable if we prefer to >>>> go that way instead of creating a core library. >>>> >>> I think it would make sense from a build environment point of view, in that it >>> allows library specific flags to be incorporated properly. I think the only >>> downside is that the individual libraries still need to be carried around >>> (though they can be ignored from an application build/run standpoint). >>> You're question should probably be asked of people using COMBINED_LIBS >>> currently to make sure that meets their needs, though I think it will. >>> >>> Neil >>> >> So I just realized that I was not having into account a possible scenario, where >> we have an app built with static dpdk libs then loading a dso with -d option. >> > This is very true, but I was under the impression that the only things that were > dlopen-able were PMD's, which would not be part of the core library. Was I > mistaken? As far as I know you are right that only PMDs are being dlopen. The proposed patch though, added DT_NEEDED entries for PMDs too, so they would need to be left empty for them to work in such scenario. Is that reasonable? Regards, Sergio >> In such case, because the pmd would have DT_NEEDED entries, dlopen will fail. >> So to enable such scenario we would need to build PMDs without DT_NEEDED >> entries. >> >> Thoughts? >> > As I mentioned above I thought the only thing that would typically be referenced > via dlopen would be libraries that were not part of the unified core library. > if thats not the case, then yes, we need a little more thought here > Neil > >> Regards, >> Sergio >>