> From: Neil Horman [mailto:nhorman at tuxdriver.com] > Sent: Thursday, January 29, 2015 4:39 PM > To: Gonzalez Monroy, Sergio > Cc: dev at dpdk.org > Subject: Re: [dpdk-dev] [PATCH 0/8] Improve build process > > On Thu, Jan 29, 2015 at 03:20:03PM +0000, Sergio Gonzalez Monroy wrote: > > This patch series improves the DPDK build system mostly for shared > > libraries (and a few nits for static libraries) with the following goals: > > - Create a library containing core DPDK libraries (librte_eal, > > librte_malloc, librte_mempool, librte_mbuf and librte_ring). > > The idea of core libraries is to group those libraries that are > > always required (and have interdependencies) for any DPDK application. > > - Remove config option to build a combined library. > > - For shared libraries, explicitly link against dependant > > libraries (adding entries to DT_NEEDED). > > - Update app linking flags for static/shared DPDK libs. > > > > Sergio Gonzalez Monroy (8): > > mk: remove combined library and related options > > core: create new librte_core > > mk: new corelib makefile > > lib: update DEPDIRS variable > > lib: set LDLIBS for each library > > mk: use LDLIBS when linking shared libraries > > mk: update LDLIBS for app building > > mk: add -lpthread to linuxapp EXECENV_LDLIBS > > > > config/common_bsdapp | 6 -- > > config/common_linuxapp | 6 -- > > config/defconfig_ppc_64-power8-linuxapp-gcc | 2 - > > lib/Makefile | 1 - > > lib/librte_acl/Makefile | 5 +- > > lib/librte_cfgfile/Makefile | 4 +- > > lib/librte_cmdline/Makefile | 6 +- > > lib/librte_core/Makefile | 45 +++++++++++++ > > lib/librte_distributor/Makefile | 5 +- > > lib/librte_eal/bsdapp/eal/Makefile | 3 +- > > lib/librte_eal/linuxapp/eal/Makefile | 3 +- > > lib/librte_ether/Makefile | 4 +- > > lib/librte_hash/Makefile | 4 +- > > lib/librte_ip_frag/Makefile | 6 +- > > lib/librte_ivshmem/Makefile | 4 +- > > lib/librte_kni/Makefile | 6 +- > > lib/librte_kvargs/Makefile | 6 +- > > lib/librte_lpm/Makefile | 6 +- > > lib/librte_malloc/Makefile | 2 +- > > lib/librte_mbuf/Makefile | 2 +- > > lib/librte_mempool/Makefile | 2 +- > > lib/librte_meter/Makefile | 4 +- > > lib/librte_pipeline/Makefile | 3 + > > lib/librte_pmd_af_packet/Makefile | 5 +- > > lib/librte_pmd_bond/Makefile | 7 +- > > lib/librte_pmd_e1000/Makefile | 8 ++- > > lib/librte_pmd_enic/Makefile | 8 ++- > > lib/librte_pmd_i40e/Makefile | 8 ++- > > lib/librte_pmd_ixgbe/Makefile | 8 ++- > > lib/librte_pmd_pcap/Makefile | 5 +- > > lib/librte_pmd_ring/Makefile | 6 +- > > lib/librte_pmd_virtio/Makefile | 7 +- > > lib/librte_pmd_vmxnet3/Makefile | 8 ++- > > lib/librte_pmd_xenvirt/Makefile | 8 ++- > > lib/librte_port/Makefile | 8 +-- > > lib/librte_power/Makefile | 4 +- > > lib/librte_ring/Makefile | 2 +- > > lib/librte_sched/Makefile | 7 +- > > lib/librte_table/Makefile | 8 +-- > > lib/librte_timer/Makefile | 6 +- > > lib/librte_vhost/Makefile | 9 +-- > > mk/exec-env/linuxapp/rte.vars.mk | 2 + > > mk/rte.app.mk | 53 ++++----------- > > mk/rte.corelib.mk | 84 +++++++++++++++++++++++ > > mk/rte.lib.mk | 49 +++----------- > > mk/rte.sdkbuild.mk | 3 - > > mk/rte.sharelib.mk | 101 > > ---------------------------- > > mk/rte.vars.mk | 9 --- > > 48 files changed, 276 insertions(+), 282 deletions(-) create mode > > 100644 lib/librte_core/Makefile create mode 100644 mk/rte.corelib.mk > > delete mode 100644 mk/rte.sharelib.mk > > > > -- > > 1.9.3 > > > > > Something occured to me thinking about this patch set. I noticed recently > that different rules are used to build the shared combined lib from the > individual shared objects. The implication here is that linker options > specified > in individual make files (like the LIBABIVER and EXPORT_MAP options in my > ABI versioning script) get ignored, which is bad. Any other file specific > linker > options (like <file>_LDFLAGS specified in individual library makefiles are > getting dropped for the combined lib. > > It seems like it would be better if the combined libs were manufactured as > linker scripts themselves (textfiles that used linker directives to include > individual libraries under the covers (see /lib64/libc.so for an example). > > The disadvantage of such an approach are fairly minimal. With such a > combined library, you still need to install individual libraries, but for > applications that wish to link and run against a single dpdk library will > still work > just as they currently do, you can link to just a single library. > > The advantage is clear however. By following a linker script aproach, objects > build as separate libraries are built exactly the same way, using the same > rules with the same options. It reduces the dpdk build environment size and > complexity, and reduces the opportunity for bugs to creep in from forgetting > to add build options to multiple locations. It also provides a more granular > approach for grouping files. Creating a dpdk core library becomes a matter of > creating a one line linker script named libdpdk_core.so, rather than re- > arraning sections of the build system. > > Thoughts? > Neil > Hi Neil,
I think that is a very interesting approach. I have tried to do something similar in this patch by removing rte.sharelib.mk and just having rte.lib.mk to do the linking, leaving as you suggest a single file to modify anything related to building libs. I do think however that your proposal is an improvement over the current patch. So basically we want: - get rid of rte.corelib.mk - generate librte_core.so linker script grouping core libs - we do not modify DEPDIR variables - when setting LDLIBS to each lib, we do specify -lrte_core, right? Regards, Sergio
