775bc8ada8
libbpf has three levels of priority for output messages: warn, info, debug. By default, debug output is not printed to the console. Add a new "--debug" (short name: "-d") option to bpftool to print libbpf logs for all three levels. Internally, we simply use the function provided by libbpf to replace the default printing function by one that prints logs regardless of their level. v2: - Remove the possibility to select the log-levels to use (v1 offered a combination of "warn", "info" and "debug"). - Rename option and offer a short name: -d|--debug. - Add option description to all bpftool manual pages (instead of bpftool-prog.rst only), as all commands use libbpf. Signed-off-by: Quentin Monnet <quentin.monnet@netronome.com> Reviewed-by: Jakub Kicinski <jakub.kicinski@netronome.com> Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
232 lines
6.4 KiB
ReStructuredText
232 lines
6.4 KiB
ReStructuredText
================
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bpftool-btf
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================
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-------------------------------------------------------------------------------
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tool for inspection of BTF data
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-------------------------------------------------------------------------------
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:Manual section: 8
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SYNOPSIS
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========
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**bpftool** [*OPTIONS*] **btf** *COMMAND*
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*OPTIONS* := { { **-j** | **--json** } [{ **-p** | **--pretty** }] }
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*COMMANDS* := { **dump** | **help** }
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BTF COMMANDS
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=============
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| **bpftool** **btf dump** *BTF_SRC* [**format** *FORMAT*]
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| **bpftool** **btf help**
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| *BTF_SRC* := { **id** *BTF_ID* | **prog** *PROG* | **map** *MAP* [{**key** | **value** | **kv** | **all**}] | **file** *FILE* }
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| *FORMAT* := { **raw** | **c** }
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| *MAP* := { **id** *MAP_ID* | **pinned** *FILE* }
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| *PROG* := { **id** *PROG_ID* | **pinned** *FILE* | **tag** *PROG_TAG* }
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DESCRIPTION
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===========
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**bpftool btf dump** *BTF_SRC*
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Dump BTF entries from a given *BTF_SRC*.
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When **id** is specified, BTF object with that ID will be
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loaded and all its BTF types emitted.
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When **map** is provided, it's expected that map has
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associated BTF object with BTF types describing key and
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value. It's possible to select whether to dump only BTF
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type(s) associated with key (**key**), value (**value**),
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both key and value (**kv**), or all BTF types present in
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associated BTF object (**all**). If not specified, **kv**
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is assumed.
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When **prog** is provided, it's expected that program has
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associated BTF object with BTF types.
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When specifying *FILE*, an ELF file is expected, containing
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.BTF section with well-defined BTF binary format data,
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typically produced by clang or pahole.
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**format** option can be used to override default (raw)
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output format. Raw (**raw**) or C-syntax (**c**) output
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formats are supported.
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**bpftool btf help**
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Print short help message.
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OPTIONS
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=======
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-h, --help
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Print short generic help message (similar to **bpftool help**).
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-V, --version
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Print version number (similar to **bpftool version**).
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-j, --json
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Generate JSON output. For commands that cannot produce JSON, this
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option has no effect.
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-p, --pretty
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Generate human-readable JSON output. Implies **-j**.
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-d, --debug
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Print all logs available from libbpf, including debug-level
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information.
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EXAMPLES
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========
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**# bpftool btf dump id 1226**
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::
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[1] PTR '(anon)' type_id=2
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[2] STRUCT 'dummy_tracepoint_args' size=16 vlen=2
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'pad' type_id=3 bits_offset=0
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'sock' type_id=4 bits_offset=64
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[3] INT 'long long unsigned int' size=8 bits_offset=0 nr_bits=64 encoding=(none)
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[4] PTR '(anon)' type_id=5
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[5] FWD 'sock' fwd_kind=union
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This gives an example of default output for all supported BTF kinds.
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**$ cat prog.c**
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::
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struct fwd_struct;
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enum my_enum {
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VAL1 = 3,
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VAL2 = 7,
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};
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typedef struct my_struct my_struct_t;
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struct my_struct {
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const unsigned int const_int_field;
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int bitfield_field: 4;
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char arr_field[16];
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const struct fwd_struct *restrict fwd_field;
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enum my_enum enum_field;
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volatile my_struct_t *typedef_ptr_field;
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};
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union my_union {
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int a;
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struct my_struct b;
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};
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struct my_struct struct_global_var __attribute__((section("data_sec"))) = {
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.bitfield_field = 3,
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.enum_field = VAL1,
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};
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int global_var __attribute__((section("data_sec"))) = 7;
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__attribute__((noinline))
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int my_func(union my_union *arg1, int arg2)
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{
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static int static_var __attribute__((section("data_sec"))) = 123;
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static_var++;
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return static_var;
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}
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**$ bpftool btf dump file prog.o**
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::
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[1] PTR '(anon)' type_id=2
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[2] UNION 'my_union' size=48 vlen=2
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'a' type_id=3 bits_offset=0
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'b' type_id=4 bits_offset=0
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[3] INT 'int' size=4 bits_offset=0 nr_bits=32 encoding=SIGNED
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[4] STRUCT 'my_struct' size=48 vlen=6
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'const_int_field' type_id=5 bits_offset=0
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'bitfield_field' type_id=3 bits_offset=32 bitfield_size=4
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'arr_field' type_id=8 bits_offset=40
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'fwd_field' type_id=10 bits_offset=192
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'enum_field' type_id=14 bits_offset=256
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'typedef_ptr_field' type_id=15 bits_offset=320
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[5] CONST '(anon)' type_id=6
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[6] INT 'unsigned int' size=4 bits_offset=0 nr_bits=32 encoding=(none)
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[7] INT 'char' size=1 bits_offset=0 nr_bits=8 encoding=SIGNED
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[8] ARRAY '(anon)' type_id=7 index_type_id=9 nr_elems=16
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[9] INT '__ARRAY_SIZE_TYPE__' size=4 bits_offset=0 nr_bits=32 encoding=(none)
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[10] RESTRICT '(anon)' type_id=11
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[11] PTR '(anon)' type_id=12
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[12] CONST '(anon)' type_id=13
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[13] FWD 'fwd_struct' fwd_kind=union
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[14] ENUM 'my_enum' size=4 vlen=2
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'VAL1' val=3
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'VAL2' val=7
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[15] PTR '(anon)' type_id=16
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[16] VOLATILE '(anon)' type_id=17
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[17] TYPEDEF 'my_struct_t' type_id=4
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[18] FUNC_PROTO '(anon)' ret_type_id=3 vlen=2
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'arg1' type_id=1
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'arg2' type_id=3
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[19] FUNC 'my_func' type_id=18
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[20] VAR 'struct_global_var' type_id=4, linkage=global-alloc
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[21] VAR 'global_var' type_id=3, linkage=global-alloc
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[22] VAR 'my_func.static_var' type_id=3, linkage=static
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[23] DATASEC 'data_sec' size=0 vlen=3
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type_id=20 offset=0 size=48
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type_id=21 offset=0 size=4
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type_id=22 offset=52 size=4
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The following commands print BTF types associated with specified map's key,
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value, both key and value, and all BTF types, respectively. By default, both
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key and value types will be printed.
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**# bpftool btf dump map id 123 key**
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::
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[39] TYPEDEF 'u32' type_id=37
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**# bpftool btf dump map id 123 value**
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::
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[86] PTR '(anon)' type_id=87
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**# bpftool btf dump map id 123 kv**
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::
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[39] TYPEDEF 'u32' type_id=37
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[86] PTR '(anon)' type_id=87
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**# bpftool btf dump map id 123 all**
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::
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[1] PTR '(anon)' type_id=0
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.
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.
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.
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[2866] ARRAY '(anon)' type_id=52 index_type_id=51 nr_elems=4
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All the standard ways to specify map or program are supported:
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**# bpftool btf dump map id 123**
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**# bpftool btf dump map pinned /sys/fs/bpf/map_name**
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**# bpftool btf dump prog id 456**
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**# bpftool btf dump prog tag b88e0a09b1d9759d**
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**# bpftool btf dump prog pinned /sys/fs/bpf/prog_name**
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SEE ALSO
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========
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**bpf**\ (2),
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**bpf-helpers**\ (7),
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**bpftool**\ (8),
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**bpftool-map**\ (8),
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**bpftool-prog**\ (8),
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**bpftool-cgroup**\ (8),
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**bpftool-feature**\ (8),
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**bpftool-net**\ (8),
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**bpftool-perf**\ (8)
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