perf tools: Allow to link with libbpf dynamicaly

2019-11-26T14:17:45Z

Currently we support only static linking with kernel's libbpf (tools/lib/bpf). This patch adds libbpf package detection and support to link perf with it dynamically. The libbpf package status is displayed with: $ make VF=1 Auto-detecting system features: ... ... libbpf: [ on ] It's not checked by default, because it's quite new. Once it's on most distros we can switch it on. For the same reason it's not added to the test-all check. Perf does not need advanced version of libbpf, so we can check just for the base bpf_object__open function. Adding new compile variable to detect libbpf package and link bpf dynamically: $ make LIBBPF_DYNAMIC=1 ... LINK perf $ ldd perf | grep bpf libbpf.so.0 => /lib64/libbpf.so.0 (0x00007f46818bc000) If libbpf is not installed, build stops with: Makefile.config:486: *** Error: No libbpf devel library found,\ please install libbpf-devel. Stop. Committer testing: $ make LIBBPF_DYNAMIC=1 -C tools/perf O=/tmp/build/perf make: Entering directory '/home/acme/git/perf/tools/perf' BUILD: Doing 'make -j8' parallel build Makefile.config:493: *** Error: No libbpf devel library found, please install libbpf-devel. Stop. make[1]: *** [Makefile.perf:225: sub-make] Error 2 make: *** [Makefile:70: all] Error 2 make: Leaving directory '/home/acme/git/perf/tools/perf' $ Signed-off-by: Jiri Olsa Tested-by: Arnaldo Carvalho de Melo Cc: Toke Høiland-Jørgensen Cc: Alexander Shishkin Cc: Alexei Starovoitov Cc: Andrii Nakryiko Cc: Daniel Borkmann Cc: Jesper Dangaard Brouer Cc: Martin KaFai Lau Cc: Michael Petlan Cc: Namhyung Kim Cc: Peter Zijlstra Cc: Song Liu Cc: Yonghong Song Cc: bpf@vger.kernel.org Cc: netdev@vger.kernel.org Link: http://lore.kernel.org/lkml/20191126121253.28253-1-jolsa@kernel.org Signed-off-by: Arnaldo Carvalho de Melo

linux-dev/tools/build/feature/test-libbpf.c, branch linus/master

perf tools: Allow to link with libbpf dynamicaly