[dpdk-dev] Questions on DPDK pkg-config

[Bruce Richardson]

On Wed, Sep 23, 2020 at 07:21:16PM +0100, Harris, James R wrote:
>    Hi,
> 
> 
>    SPDK would like to use DPDK’s pkg-config files rather than rolling our
>    own linker arguments.  I’m running into a couple of issues – one looks
>    like a bug, the other is not as clear.
> 
> 
>    First is the use of --as-needed
>    ([1]https://github.com/DPDK/dpdk/commit/b98447077b0609750c10b84b7b2e7be
>    0c8504fad).  We have run into problems with this in the past,
>    specifically related to the rte_mempool_ring MEMPOOL_REGISTER_OPS
>    constructor functions.  --as-needed results in similar behavior to
>    omitting --whole-archive when using static libraries – meaning the
>    constructor function doesn’t get called and we cannot create any
>    mempools since there are no registered mempool_ops.  I think this would
>    also affect other uses of constructor functions within DPDK when using
>    pkg-config, but this rte_mempool_ring one is the only that would impact
>    SPDK so it’s the only one I’ve checked.
> 
> 
>    Second is that rte_bus_pci is not included in the pkg-config output.
>    SPDK relies on rte_bus_pci since we have our own DPDK drivers for
>    things like nvme, virtio-blk and virtio-scsi and need access to
>    rte_pci_read_config, rte_pci_write_config and rte_pci_register.
>    Perhaps we could add bus_pci to the dpdk_libraries in lib/meson.build?
> 
> 
>    Any help would be appreciated.
> 
> 
>    Thanks,
> 
> 
>    -Jim
> 
Hi Jim,

what command are you using to get the libs etc. from pkg-config? For static
linking you need to pass the --static flag which will include all the libs
and drivers, including the pci bus driver. [See output below from my system after
running "ninja install"]. The --as-needed is required to prevent the shared
libs also being linked into a static build in this case.

/Bruce

$ PKG_CONFIG_PATH=/usr/local/lib/x86_64-linux-gnu/pkgconfig/ pkg-config --libs --static libdpdk
-L/usr/local/lib/x86_64-linux-gnu -Wl,--whole-archive -l:librte_common_cpt.a -l:librte_common_dpaax.a -l:librte_common_iavf.a -l:librte_common_octeontx.a -l:librte_common_octeontx2.a -l:librte_bus_dpaa.a -l:librte_bus_fslmc.a -l:librte_bus_ifpga.a -l:librte_bus_pci.a -l:librte_bus_vdev.a -l:librte_bus_vmbus.a -l:librte_mempool_bucket.a -l:librte_mempool_dpaa.a -l:librte_mempool_dpaa2.a -l:librte_mempool_octeontx.a -l:librte_mempool_octeontx2.a -l:librte_mempool_ring.a -l:librte_mempool_stack.a -l:librte_pmd_e1000.a -l:librte_pmd_ena.a -l:librte_pmd_enetc.a -l:librte_pmd_enic.a -l:librte_node.a -l:librte_graph.a -l:librte_bpf.a -l:librte_flow_classify.a -l:librte_pipeline.a -l:librte_table.a -l:librte_port.a -l:librte_fib.a -l:librte_ipsec.a -l:librte_vhost.a -l:librte_stack.a -l:librte_security.a -l:librte_sched.a -l:librte_reorder.a -l:librte_rib.a -l:librte_regexdev.a -l:librte_rawdev.a -l:librte_pdump.a -l:librte_power.a -l:librte_member.a -l:librte_lpm.a -l:librte_latencystats.a -l:librte_kni.a -l:librte_jobstats.a -l:librte_ip_frag.a -l:librte_gso.a -l:librte_gro.a -l:librte_eventdev.a -l:librte_efd.a -l:librte_distributor.a -l:librte_cryptodev.a -l:librte_compressdev.a -l:librte_cfgfile.a -l:librte_bitratestats.a -l:librte_bbdev.a -l:librte_acl.a -l:librte_timer.a -l:librte_hash.a -l:librte_metrics.a -l:librte_cmdline.a -l:librte_pci.a -l:librte_ethdev.a -l:librte_meter.a -l:librte_net.a -l:librte_mbuf.a -l:librte_mempool.a -l:librte_rcu.a -l:librte_ring.a -l:librte_eal.a -l:librte_telemetry.a -l:librte_kvargs.a -Wl,--no-whole-archive -lpcap -ljansson -Wl,--as-needed -lrte_node -lrte_graph -lrte_bpf -lrte_flow_classify -lrte_pipeline -lrte_table -lrte_port -lrte_fib -lrte_ipsec -lrte_vhost -lrte_stack -lrte_security -lrte_sched -lrte_reorder -lrte_rib -lrte_regexdev -lrte_rawdev -lrte_pdump -lrte_power -lrte_member -lrte_lpm -lrte_latencystats -lrte_kni -lrte_jobstats -lrte_ip_frag -lrte_gso -lrte_gro -lrte_eventdev -lrte_efd -lrte_distributor -lrte_cryptodev -lrte_compressdev -lrte_cfgfile -lrte_bitratestats -lrte_bbdev -lrte_acl -lrte_timer -lrte_hash -lrte_metrics -lrte_cmdline -lrte_pci -lrte_ethdev -lrte_meter -lrte_net -lrte_mbuf -lrte_mempool -lrte_rcu -lrte_ring -lrte_eal -lrte_telemetry -lrte_kvargs -pthread -lm -ldl -lfdt -lpcap