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658ac068 |
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07-Jul-2023 |
Alexander Lobakin <alobakin@pm.me> |
bpftool: Use a local bpf_perf_event_value to fix accessing its fields Fix the following error when building bpftool: CLANG profiler.bpf.o CLANG pid_iter.bpf.o skeleton/profiler.bpf.c:18:21: error: invalid application of 'sizeof' to an incomplete type 'struct bpf_perf_event_value' __uint(value_size, sizeof(struct bpf_perf_event_value)); ^ ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ tools/bpf/bpftool/bootstrap/libbpf/include/bpf/bpf_helpers.h:13:39: note: expanded from macro '__uint' tools/bpf/bpftool/bootstrap/libbpf/include/bpf/bpf_helper_defs.h:7:8: note: forward declaration of 'struct bpf_perf_event_value' struct bpf_perf_event_value; ^ struct bpf_perf_event_value is being used in the kernel only when CONFIG_BPF_EVENTS is enabled, so it misses a BTF entry then. Define struct bpf_perf_event_value___local with the `preserve_access_index` attribute inside the pid_iter BPF prog to allow compiling on any configs. It is a full mirror of a UAPI structure, so is compatible both with and w/o CO-RE. bpf_perf_event_read_value() requires a pointer of the original type, so a cast is needed. Fixes: 47c09d6a9f67 ("bpftool: Introduce "prog profile" command") Suggested-by: Andrii Nakryiko <andrii@kernel.org> Signed-off-by: Alexander Lobakin <alobakin@pm.me> Signed-off-by: Quentin Monnet <quentin@isovalent.com> Signed-off-by: Andrii Nakryiko <andrii@kernel.org> Link: https://lore.kernel.org/bpf/20230707095425.168126-5-quentin@isovalent.com
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0698ac66 |
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27-Oct-2020 |
Ian Rogers <irogers@google.com> |
tools, bpftool: Remove two unused variables. Avoid an unused variable warning. Signed-off-by: Ian Rogers <irogers@google.com> Signed-off-by: Daniel Borkmann <daniel@iogearbox.net> Reviewed-by: Tobias Klauser <tklauser@distanz.ch> Acked-by: Andrii Nakryiko <andrii@kernel.org> Link: https://lore.kernel.org/bpf/20201027233646.3434896-2-irogers@google.com
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05aca6da |
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19-Jun-2020 |
Andrii Nakryiko <andriin@fb.com> |
tools/bpftool: Generalize BPF skeleton support and generate vmlinux.h Adapt Makefile to support BPF skeleton generation beyond single profiler.bpf.c case. Also add vmlinux.h generation and switch profiler.bpf.c to use it. clang-bpf-global-var feature is extended and renamed to clang-bpf-co-re to check for support of preserve_access_index attribute, which, together with BTF for global variables, is the minimum requirement for modern BPF programs. Signed-off-by: Andrii Nakryiko <andriin@fb.com> Signed-off-by: Alexei Starovoitov <ast@kernel.org> Reviewed-by: Quentin Monnet <quentin@isovalent.com> Link: https://lore.kernel.org/bpf/20200619231703.738941-7-andriin@fb.com
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bb8dc269 |
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19-Jun-2020 |
Andrii Nakryiko <andriin@fb.com> |
tools/bpftool: Relicense bpftool's BPF profiler prog as dual-license GPL/BSD Relicense it to be compatible with the rest of bpftool files. Suggested-by: Quentin Monnet <quentin@isovalent.com> Signed-off-by: Andrii Nakryiko <andriin@fb.com> Signed-off-by: Daniel Borkmann <daniel@iogearbox.net> Link: https://lore.kernel.org/bpf/20200619222024.519774-1-andriin@fb.com
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47c09d6a |
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09-Mar-2020 |
Song Liu <songliubraving@fb.com> |
bpftool: Introduce "prog profile" command With fentry/fexit programs, it is possible to profile BPF program with hardware counters. Introduce bpftool "prog profile", which measures key metrics of a BPF program. bpftool prog profile command creates per-cpu perf events. Then it attaches fentry/fexit programs to the target BPF program. The fentry program saves perf event value to a map. The fexit program reads the perf event again, and calculates the difference, which is the instructions/cycles used by the target program. Example input and output: ./bpftool prog profile id 337 duration 3 cycles instructions llc_misses 4228 run_cnt 3403698 cycles (84.08%) 3525294 instructions # 1.04 insn per cycle (84.05%) 13 llc_misses # 3.69 LLC misses per million isns (83.50%) This command measures cycles and instructions for BPF program with id 337 for 3 seconds. The program has triggered 4228 times. The rest of the output is similar to perf-stat. In this example, the counters were only counting ~84% of the time because of time multiplexing of perf counters. Note that, this approach measures cycles and instructions in very small increments. So the fentry/fexit programs introduce noticeable errors to the measurement results. The fentry/fexit programs are generated with BPF skeletons. Therefore, we build bpftool twice. The first time _bpftool is built without skeletons. Then, _bpftool is used to generate the skeletons. The second time, bpftool is built with skeletons. Signed-off-by: Song Liu <songliubraving@fb.com> Signed-off-by: Daniel Borkmann <daniel@iogearbox.net> Reviewed-by: Quentin Monnet <quentin@isovalent.com> Acked-by: Yonghong Song <yhs@fb.com> Link: https://lore.kernel.org/bpf/20200309173218.2739965-2-songliubraving@fb.com
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