From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from smtp.tuxdriver.com (charlotte.tuxdriver.com [70.61.120.58]) by dpdk.org (Postfix) with ESMTP id 32D965690 for ; Fri, 13 Mar 2015 17:16:31 +0100 (CET) Received: from hmsreliant.think-freely.org ([2001:470:8:a08:7aac:c0ff:fec2:933b] helo=localhost) by smtp.tuxdriver.com with esmtpsa (TLSv1:AES128-SHA:128) (Exim 4.63) (envelope-from ) id 1YWSFz-0008PU-Sm; Fri, 13 Mar 2015 12:16:29 -0400 Date: Fri, 13 Mar 2015 12:16:14 -0400 From: Neil Horman To: "Gonzalez Monroy, Sergio" Message-ID: <20150313161614.GH28191@hmsreliant.think-freely.org> References: <1426177681-16931-1-git-send-email-sergio.gonzalez.monroy@intel.com> <1426177681-16931-2-git-send-email-sergio.gonzalez.monroy@intel.com> <5502C7D9.2060503@intel.com> <5502CEAB.8060801@intel.com> <20150313131719.GA28191@hmsreliant.think-freely.org> <20150313151855.GG28191@hmsreliant.think-freely.org> <55030200.4070505@intel.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <55030200.4070505@intel.com> User-Agent: Mutt/1.5.23 (2014-03-12) X-Spam-Score: -2.9 (--) X-Spam-Status: No Cc: "dev@dpdk.org" Subject: Re: [dpdk-dev] [PATCH v2 1/4] mk: Remove combined library and related options 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 Mar 2015 16:16:31 -0000 On Fri, Mar 13, 2015 at 03:28:00PM +0000, Gonzalez Monroy, Sergio wrote: > On 13/03/2015 15:18, Neil Horman wrote: > >On Fri, Mar 13, 2015 at 04:12:35PM +0200, Stefan Puiu wrote: > >>Hi, > >> > >>2 cents from a DPDK library user - I make 2 changes to the default > >>linux+gcc configuration: combine libraries and build shared libraries > >>(since I want 2 instances of the app, it didn't make sense to me to > >>link statically). I tried working with the individual libs, but adding > >>all of them with --start-group/-end-group just seemed so much more > >>painful than simply linking against one lib. I know there are some > >>Makefile variables to help with this, but I use scons for building my > >>app, so that doesn't help much. > >> > >>Of course, if that can be achieved easily after building all the > >>libraries, that's fine. But I think combining the libs makes a lot of > >>sense in many cases. > >> > >So do it, create a linker script that internally contains one line: > >INPUT(-lrte_eal -lrte_alarm -lrte_mempool ... etc) > > > >Name the file libdpdk.so > > > >then when you build your app, just link -ldpdk > > > >Done. > > > >Neil > > Plus I believe that as it currently stands, building combined shared > libraries will be broken > the moment we have different versions of any API because the linking for the > combined lib > does not use a version map. > Correct, the above is the only way to create a single library that is properly versioned, short of _only_ building a single library and exporting the version map for that (which is non-sensical, as it defeats the purpose of DSO's). > Sergio > >>Thanks, > >>Stefan. > >> > >>On Fri, Mar 13, 2015 at 3:17 PM, Neil Horman wrote: > >>>On Fri, Mar 13, 2015 at 11:48:59AM +0000, Gonzalez Monroy, Sergio wrote: > >>>>On 13/03/2015 11:34, Kavanagh, Mark B wrote: > >>>>>>On 13/03/2015 10:49, Kavanagh, Mark B wrote: > >>>>>>>>--- > >>>>>>>>config/common_bsdapp | 6 -- > >>>>>>>>config/common_linuxapp | 6 -- > >>>>>>>>config/defconfig_ppc_64-power8-linuxapp-gcc | 2 - > >>>>>>>>lib/Makefile | 1 - > >>>>>>>>mk/rte.app.mk | 12 ---- > >>>>>>>>mk/rte.lib.mk | 35 ---------- > >>>>>>>>mk/rte.sdkbuild.mk | 3 - > >>>>>>>>mk/rte.sharelib.mk | 101 ---------------------------- > >>>>>>>>mk/rte.vars.mk | 9 --- > >>>>>>>>9 files changed, 175 deletions(-) > >>>>>>>>delete mode 100644 mk/rte.sharelib.mk > >>>>>>>> > >>>>>>>>diff --git a/config/common_bsdapp b/config/common_bsdapp > >>>>>>>>index 8ff4dc2..7ee5ecf 100644 > >>>>>>>>--- a/config/common_bsdapp > >>>>>>>>+++ b/config/common_bsdapp > >>>>>>>>@@ -79,12 +79,6 @@ CONFIG_RTE_FORCE_INTRINSICS=n > >>>>>>>>CONFIG_RTE_BUILD_SHARED_LIB=n > >>>>>>>> > >>>>>>>># > >>>>>>>>-# Combine to one single library > >>>>>>>>-# > >>>>>>>>-CONFIG_RTE_BUILD_COMBINE_LIBS=n > >>>>>>>>-CONFIG_RTE_LIBNAME=intel_dpdk > >>>>>>>Hi Sergio, > >>>>>>> > >>>>>>>Removing these options breaks compatibility with OVS. While it may be feasible to link > >>>>>>to individual static libraries, in our experience, a single combined library provides a > >>>>>>much more convenient way of linking. > >>>>>>>Thanks, > >>>>>>>Mark > >>>>>>> > >>>>>>>>- > >>>>>(snip) > >>>>> > >>>>> > >>>>>>>>-endif > >>>>>>>>- > >>>>>>>>-RTE_LIBNAME := $(CONFIG_RTE_LIBNAME:"%"=%) > >>>>>>>>-ifeq ($(RTE_LIBNAME),) > >>>>>>>>-RTE_LIBNAME := intel_dpdk > >>>>>>>>endif > >>>>>>>> > >>>>>>>># RTE_TARGET is deducted from config when we are building the SDK. > >>>>>>>>-- > >>>>>>>>1.9.3 > >>>>>>Hi Mark, > >>>>>> > >>>>>>How does this patch break compatibility with OVS? > >>>>>> > >>>>>>Thanks, > >>>>>>Sergio > >>>>>Hey Sergio, > >>>>> > >>>>>We use the CONFIG_RTE_BUILD_COMBINE_LIBS and CONFIG_RTE_LINBNAME flags to build a single static DPDK library, named 'libintel_dpdk.a', which OVS links against. Removing the combined library option breaks compatibility with any application that links against the combined DPDK library. > >>>>> > >>>>>Is there a strong technical motivation for removing these options? > >>>>> > >>>>>Thanks, > >>>>>Mark > >>>> From a shared library point of view, it just does not make sense to have > >>>>applications linked against a 'combined' library that may have different > >>>>features built in it. > >>>> > >>>>Removing these options, aside from the obvious 'less build config option', > >>>>it simplifies maintenance of makefiles as we currently have a separated > >>>>makefile with specific rules just for combined library. > >>>> > >>>>It is pretty straight forward to build a single combined archive out of > >>>>multiple archives, would it be acceptable to have a script to do this? > >>>> > >>>>Thanks, > >>>>Sergio > >>>> > >>>+1 > >>> > >>>For the static case, its easy to do a post build combination of archives. For > >>>the shared library case, its equally easy to simply create a linker scripts call > >>>.so that pulls in all the individual libraries. > >>> > >>>Neil > >>> > >