Hi, as an example of where I am having trouble with shared libraries, I am trying to modify the "helloworld" example program so that I can invoke it as: "helloworld --vdev net_null0". Working by looking at the low-level dpdk-20.11 driver code, I tried adding a call to "rte_vdev_init()" to the helloworld main.c as shown in the code diffs below. When I tried to build (as shared), I got an error from the loader saying the reference to 'rte_vdev_init' is undefined.
Am I even barking up the right tree? Fred --- main.c 2021-04-20 08:17:37.895698070 -0700 +++ main.c.net_null 2021-04-20 08:24:51.958198682 -0700 @@ -14,6 +14,9 @@ #include <rte_per_lcore.h> #include <rte_lcore.h> #include <rte_debug.h> +#if 1 +#include <rte_bus_vdev.h> +#endif static int lcore_hello(__rte_unused void *arg) @@ -30,6 +33,12 @@ int ret; unsigned lcore_id; +#if 1 + ret = rte_vdev_init("net_null", NULL); + if (ret < 0) + rte_panic("Cannot init net_null\n"); +#endif + ret = rte_eal_init(argc, argv); if (ret < 0) rte_panic("Cannot init EAL\n"); cc -O3 -include rte_config.h -march=native -I/usr/local/include -DALLOW_EXPERIMENTAL_API main.c -o build/helloworld-shared -L/usr/local/lib/x86_64-linux-gnu -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 /tmp/ccgU3Rpi.o: In function `main': main.c:(.text.startup+0x15): undefined reference to `rte_vdev_init' collect2: error: ld returned 1 exit status Makefile:32: recipe for target 'build/helloworld-shared' failed make: *** [build/helloworld-shared] Error 1 > -----Original Message----- > From: users [mailto:users-boun...@dpdk.org] On Behalf Of Templin (US), Fred L > Sent: Tuesday, April 20, 2021 9:25 AM > To: users@dpdk.org; Stephen Hemminger <step...@networkplumber.org> > Subject: [dpdk-users] dpdk-20.11 and shared libraries > > Hi, I have put a lot of time into learning about dpdk-20.11 but I have not > yet found > documentation on how to use it with shared libraries. In dpdk-20.11, the > examples > are all built as "static" by default meaning that the entire kitchen sink of > all DPDK > libraries are linked in during the "ld" phase and the resulting binary is > huge. When > built as "static", the examples all appear to work fine as everything is > loaded by > default at runtime. > > When I build the examples as "shared", however, the story is completely > different. > Examples that run fine as "static" do not work at all when built as "shared". > It is > clear that somehow the build procedure is not giving adequate instructions to > the > loader so that all necessary libraries will be ready to go at runtime. > > I believe what needs to happen is that initialization code needs to be added > to the > example "main.c" modules to initialize functions that will be needed by lower > levels > but that are not being picked up on by the loader. But, I can find no > documentation > for how to do this. In my next message, I will send a code example of what I > have > tried so far. > > Stephen, can you provide guidance on how to work with dpdk-20.11 in shared > library environments? I would be happy to be pointed to any documentation > I may be missing. > > Thanks - Fred >