All, I just noticed that the "dpdk-helloworld" binary was massively large because it was built with the "static" option. When I build it as "shared", the resulting binary is appropriately small. However, when I build it as "shared" I get the same failure case that I describe for what I am getting out of my testprog below.
I would greatly prefer to link DPDK into my testprog as "shared" and not "static". But, if I link it as "shared" is there some sort of pre-initialization sequence I need to execute before calling "rte_eal_init()"? I would be happy to be pointed to the appropriate documentation. Thanks - Fred > -----Original Message----- > From: users [mailto:users-boun...@dpdk.org] On Behalf Of Templin (US), Fred L > Sent: Friday, April 16, 2021 12:32 PM > To: users@dpdk.org > Subject: [dpdk-users] Problems linking DPDK-20.11 libraries to another program > > Hello, I am at an impasse trying to link DPDK-20.11 libraries with another > program. > The other program (call it "testprog") is a large C source code application > that uses > standard linux open source build and compile facilities, including Makefiles, > gcc, > configure, etc. It is built from about 190 *.[ch] files, with one defining a > single > main() for the entire application. > > I read the DPDK documentation and tried to link the libraries in using the > "pkg-config" facility per the recommendations, but I was unable to get > pkg-config > to execute out of the "testprog" Makefile. So, I issued the following > commands to > obtain the results of running pkg-config: > > fltemplin@aer-dtn:~$ pkg-config --cflags libdpdk > fltemplin@aer-dtn:~$ pkg-config --libs libdpdk > > I then added the results of the commands to the "testprog" Makefile by adding > the following lines: > > CFLAGS += -include rte_config.h -march=native -I/usr/local/include > LDFLAGS += -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 > > Next, I modified the DPDK "helloworld" example main.c to link it into > "testprog" by > changing the name to "hello.c" and changing the "main()" declaration to a > function > call called: "testprog_hello()" which I then called from one of my other > "testprog" > C modules. The diffs for how I modified the helloworld code appear at the end > of > this message. > > I was then able to run "make" in the "testprog" directory, and the build > compiled > and appeared to link everything just fine. However, it appears that the > resulting > "tesprog" binary only increased in size by about 4% over the size it normally > builds > to without the DPDK libraries. This seems at odds with the fact that the DPDK > "dpdk-helloworld" binary is massively large in comparison especially > considering > that the helloworld main.c is only 47 lines of C code! The sizes of the > binaries > are shown below: > > fltemplin@aer-dtn:~$ cd ~/src/testprog/build > fltemplin@aer-dtn:~/src/testprog/build$ ls -l testprog* > -rwxr-xr-x 1 fltemplin fltemplin 4991800 Apr 16 10:25 testprog.nodpdk > -rwxr-xr-x 1 fltemplin fltemplin 5186816 Apr 16 10:32 testprog.withdpdk > fltemplin@aer-dtn~/src/testpog/build$: cd > ~/src/DPDK/dpdk-20.11/build/examples/ > fltemplin@aer-dtn:~/src/DPDK/dpdk-20.11/build/examples$ ls -l dpdk-helloworld > -rwxr-xr-x 1 fltemplin fltemplin 17834608 Apr 14 14:30 dpdk-helloworld > > The next question then came to whether my combined testprog/dpdk code > would run the same as the native DPDK helloworld example. I ultimately want > to set up a NULL network interface when I call "rte_eal_init (argc, argv)" and > so I tried issuing the following invocation of dpdk-helloworld: > > fltemplin@aer-dtn:~$ sudo ./dpdk-helloworld --vdev net_null0 > EAL: Detected 1 lcore(s) > EAL: Detected 1 NUMA nodes > EAL: Multi-process socket /var/run/dpdk/rte/mp_socket > EAL: Selected IOVA mode 'PA' > EAL: Probing VFIO support... > EAL: VFIO support initialized > EAL: Invalid NUMA socket, default to 0 > EAL: Invalid NUMA socket, default to 0 > EAL: No legacy callbacks, legacy socket not created > hello from core 0 > > So, as you can see, dpdk-helloworld passes the "--vnet" and "net_null0" > arguments > to "rte_eal_init()", which recognizes the arguments and returns success. But, > when > I call "rte_eal_init()" out of my testprog using the same arguments the DPDK > service > returns the following: > > fltemplin@aer-dtn:~$ sudo ./testprog > EAL: Detected 1 lcore(s) > EAL: Detected 1 NUMA nodes > EAL: failed to parse device "net_null0" > EAL: Unable to parse device 'net_null0' > PANIC in testprog_hello(): > Cannot init EAL > > This appears to me that DPDK is failing to initialize basic data structures > when run out of my testprog that are initialized fine when run out of the > dpdk-helloworld binary. That the code compiles and links is encouraging, > but the fact that the binary size for my combined testprog/helloworld is > significantly smaller than the size of dpdk-helloworld alone seems very > suspicious. I feel I must be missing something very basic - does anyone > recognize these conditions and have insights about how to fix? > > Thanks - Fred > > As previously mentioned, see below for my source code changes to link > helloworld into testprog: > > *** ~/src/DPDK/dpdk-20.11/examples/helloworld/main.c 2021-04-14 > 13:59:16.224073175 -0700 > --- ~/src/testprog/src/hello.c 2021-04-16 09:46:42.142210166 -0700 > *************** > *** 2,7 **** > --- 2,14 ---- > * Copyright(c) 2010-2014 Intel Corporation > */ > > + #ifdef HAVE_CONFIG_H > + #include "config.h" > + #elif defined(_MSC_VER) > + #include "config-msvc.h" > + #endif > + > + #ifdef ENABLE_DPDK_TEST > #include <stdio.h> > #include <string.h> > #include <stdint.h> > *************** > *** 25,32 **** > --- 32,47 ---- > } > > int > + #ifdef ENABLE_DPDK_TEST > + testprog_hello() > + { > + char *args[] = { "openvpn", "--vdev", "net_null0" }; > + char **argv = args; > + int argc = 3; > + #else > main(int argc, char **argv) > { > + #endif > int ret; > unsigned lcore_id; > > *************** > *** 45,47 **** > --- 60,63 ---- > rte_eal_mp_wait_lcore(); > return 0; > } > + #endif
