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2021-12-14selftests/bpf: Stop using bpf_object__find_program_by_title API.Kui-Feng Lee1-10/+10
bpf_object__find_program_by_title is going to be deprecated. Replace all use cases in tools/testing/selftests/bpf with bpf_object__find_program_by_name or bpf_object__for_each_program. Signed-off-by: Kui-Feng Lee <kuifeng@fb.com> Signed-off-by: Andrii Nakryiko <andrii@kernel.org> Link: https://lore.kernel.org/bpf/20211214035931.1148209-2-kuifeng@fb.com
2021-05-25selftests/bpf: Turn on libbpf 1.0 mode and fix all IS_ERR checksAndrii Nakryiko1-6/+6
Turn ony libbpf 1.0 mode. Fix all the explicit IS_ERR checks that now will be broken because libbpf returns NULL on error (and sets errno). Fix ASSERT_OK_PTR and ASSERT_ERR_PTR to work for both old mode and new modes and use them throughout selftests. This is trivial to do by using libbpf_get_error() API that all libbpf users are supposed to use, instead of IS_ERR checks. A bunch of checks also did explicit -1 comparison for various fd-returning APIs. Such checks are replaced with >= 0 or < 0 cases. There were also few misuses of bpf_object__find_map_by_name() in test_maps. Those are fixed in this patch as well. Signed-off-by: Andrii Nakryiko <andrii@kernel.org> Signed-off-by: Alexei Starovoitov <ast@kernel.org> Acked-by: John Fastabend <john.fastabend@gmail.com> Acked-by: Toke Høiland-Jørgensen <toke@redhat.com> Link: https://lore.kernel.org/bpf/20210525035935.1461796-3-andrii@kernel.org
2020-09-28selftests: Remove fmod_ret from test_overheadToke Høiland-Jørgensen1-13/+1
The test_overhead prog_test included an fmod_ret program that attached to __set_task_comm() in the kernel. However, this function was never listed as allowed for return modification, so this only worked because of the verifier skipping tests when a trampoline already existed for the attach point. Now that the verifier checks have been fixed, remove fmod_ret from the test so it works again. Fixes: 4eaf0b5c5e04 ("selftest/bpf: Fmod_ret prog and implement test_overhead as part of bench") Acked-by: Andrii Nakryiko <andriin@fb.com> Signed-off-by: Toke Høiland-Jørgensen <toke@redhat.com> Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2020-05-13selftest/bpf: Fmod_ret prog and implement test_overhead as part of benchAndrii Nakryiko1-1/+13
Add fmod_ret BPF program to existing test_overhead selftest. Also re-implement user-space benchmarking part into benchmark runner to compare results. Results with ./bench are consistently somewhat lower than test_overhead's, but relative performance of various types of BPF programs stay consisten (e.g., kretprobe is noticeably slower). This slowdown seems to be coming from the fact that test_overhead is single-threaded, while benchmark always spins off at least one thread for producer. This has been confirmed by hacking multi-threaded test_overhead variant and also single-threaded bench variant. Resutls are below. run_bench_rename.sh script from benchs/ subdirectory was used to produce results for ./bench. Single-threaded implementations =============================== /* bench: single-threaded, atomics */ base : 4.622 ± 0.049M/s kprobe : 3.673 ± 0.052M/s kretprobe : 2.625 ± 0.052M/s rawtp : 4.369 ± 0.089M/s fentry : 4.201 ± 0.558M/s fexit : 4.309 ± 0.148M/s fmodret : 4.314 ± 0.203M/s /* selftest: single-threaded, no atomics */ task_rename base 4555K events per sec task_rename kprobe 3643K events per sec task_rename kretprobe 2506K events per sec task_rename raw_tp 4303K events per sec task_rename fentry 4307K events per sec task_rename fexit 4010K events per sec task_rename fmod_ret 3984K events per sec Multi-threaded implementations ============================== /* bench: multi-threaded w/ atomics */ base : 3.910 ± 0.023M/s kprobe : 3.048 ± 0.037M/s kretprobe : 2.300 ± 0.015M/s rawtp : 3.687 ± 0.034M/s fentry : 3.740 ± 0.087M/s fexit : 3.510 ± 0.009M/s fmodret : 3.485 ± 0.050M/s /* selftest: multi-threaded w/ atomics */ task_rename base 3872K events per sec task_rename kprobe 3068K events per sec task_rename kretprobe 2350K events per sec task_rename raw_tp 3731K events per sec task_rename fentry 3639K events per sec task_rename fexit 3558K events per sec task_rename fmod_ret 3511K events per sec /* selftest: multi-threaded, no atomics */ task_rename base 3945K events per sec task_rename kprobe 3298K events per sec task_rename kretprobe 2451K events per sec task_rename raw_tp 3718K events per sec task_rename fentry 3782K events per sec task_rename fexit 3543K events per sec task_rename fmod_ret 3526K events per sec Note that the fact that ./bench benchmark always uses atomic increments for counting, while test_overhead doesn't, doesn't influence test results all that much. Signed-off-by: Andrii Nakryiko <andriin@fb.com> Signed-off-by: Alexei Starovoitov <ast@kernel.org> Acked-by: John Fastabend <john.fastabend@gmail.com> Acked-by: Yonghong Song <yhs@fb.com> Link: https://lore.kernel.org/bpf/20200512192445.2351848-4-andriin@fb.com
2020-01-09selftests/bpf: Restore original comm in test_overheadStanislav Fomichev1-1/+7
test_overhead changes task comm in order to estimate BPF trampoline overhead but never sets the comm back to the original one. We have the tests (like core_reloc.c) that have 'test_progs' as hard-coded expected comm, so let's try to preserve the original comm. Currently, everything works because the order of execution is: first core_recloc, then test_overhead; but let's make it a bit future-proof. Other related changes: use 'test_overhead' as new comm instead of 'test' to make it easy to debug and drop '\n' at the end. Signed-off-by: Stanislav Fomichev <sdf@google.com> Signed-off-by: Alexei Starovoitov <ast@kernel.org> Acked-by: Petar Penkov <ppenkov@google.com> Acked-by: Song Liu <songliubraving@fb.com> Link: https://lore.kernel.org/bpf/20200108192132.189221-1-sdf@google.com
2019-11-24selftests/bpf: Add BPF trampoline performance testAlexei Starovoitov1-0/+142
Add a test that benchmarks different ways of attaching BPF program to a kernel function. Here are the results for 2.4Ghz x86 cpu on a kernel without mitigations: $ ./test_progs -n 49 -v|grep events task_rename base 2743K events per sec task_rename kprobe 2419K events per sec task_rename kretprobe 1876K events per sec task_rename raw_tp 2578K events per sec task_rename fentry 2710K events per sec task_rename fexit 2685K events per sec On a kernel with retpoline: $ ./test_progs -n 49 -v|grep events task_rename base 2401K events per sec task_rename kprobe 1930K events per sec task_rename kretprobe 1485K events per sec task_rename raw_tp 2053K events per sec task_rename fentry 2351K events per sec task_rename fexit 2185K events per sec All 5 approaches: - kprobe/kretprobe in __set_task_comm() - raw tracepoint in trace_task_rename() - fentry/fexit in __set_task_comm() are roughly equivalent. __set_task_comm() by itself is quite fast, so any extra instructions add up. Until BPF trampoline was introduced the fastest mechanism was raw tracepoint. kprobe via ftrace was second best. kretprobe is slow due to trap. New fentry/fexit methods via BPF trampoline are clearly the fastest and the difference is more pronounced with retpoline on, since BPF trampoline doesn't use indirect jumps. Signed-off-by: Alexei Starovoitov <ast@kernel.org> Signed-off-by: Daniel Borkmann <daniel@iogearbox.net> Acked-by: John Fastabend <john.fastabend@gmail.com> Link: https://lore.kernel.org/bpf/20191122011515.255371-1-ast@kernel.org
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