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perf record: Add --setup-filter option

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To allow BPF filters for unprivileged users it needs to pin the BPF
objects to BPF-fs first.  Let's add a new option to pin and unpin the
objects easily.  I'm not sure 'perf record' is a right place to do this
but I don't have a better idea right now.

  $ sudo perf record --setup-filter pin

The above command would pin BPF program and maps for the filter when the
system has BPF-fs (usually at /sys/fs/bpf/).  To unpin the objects,
users can run the following command (as root).

  $ sudo perf record --setup-filter unpin

Committer testing:

  root@number:~# perf record --setup-filter pin
  root@number:~# ls -la /sys/fs/bpf/perf_filter/
  total 0
  drwxr-xr-x. 2 root root 0 Jul 31 10:43 .
  drwxr-xr-t. 3 root root 0 Jul 31 10:43 ..
  -rw-rw-rw-. 1 root root 0 Jul 31 10:43 dropped
  -rw-rw-rw-. 1 root root 0 Jul 31 10:43 filters
  -rwxrwxrwx. 1 root root 0 Jul 31 10:43 perf_sample_filter
  -rw-rw-rw-. 1 root root 0 Jul 31 10:43 pid_hash
  -rw-------. 1 root root 0 Jul 31 10:43 sample_f_rodata
  root@number:~# ls -la /sys/fs/bpf/perf_filter/perf_sample_filter
  -rwxrwxrwx. 1 root root 0 Jul 31 10:43 /sys/fs/bpf/perf_filter/perf_sample_filter
  root@number:~#

Signed-off-by: Namhyung Kim <namhyung@kernel.org>
Tested-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Ian Rogers <irogers@google.com>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: KP Singh <kpsingh@kernel.org>
Cc: Kan Liang <kan.liang@linux.intel.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Song Liu <song@kernel.org>
Cc: Stephane Eranian <eranian@google.com>
Cc: bpf@vger.kernel.org
Link: https://lore.kernel.org/r/20240703223035.2024586-8-namhyung@kernel.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
This commit is contained in:
Namhyung Kim 2024-07-03 15:30:34 -07:00 committed by Arnaldo Carvalho de Melo
parent 73bf63a475
commit 3dee4b83a6
2 changed files with 20 additions and 0 deletions
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5
tools/perf/Documentation/perf-record.txt
View File

@ -828,6 +828,11 @@ filtered through the mask provided by -C option.
only, as of now. So the applications built without the frame
pointer might see bogus addresses.
--setup-filter=<action>::
Prepare BPF filter to be used by regular users. The action should be
either "pin" or "unpin". The filter can be used after it's pinned.
include::intel-hybrid.txt[]
SEE ALSO

15
tools/perf/builtin-record.c
View File

@ -171,6 +171,7 @@ struct record {
bool timestamp_filename;
bool timestamp_boundary;
bool off_cpu;
const char *filter_action;
struct switch_output switch_output;
unsigned long long samples;
unsigned long output_max_size; /* = 0: unlimited */
@ -3557,6 +3558,8 @@ static struct option __record_options[] = {
"write collected trace data into several data files using parallel threads",
record__parse_threads),
OPT_BOOLEAN(0, "off-cpu", &record.off_cpu, "Enable off-cpu analysis"),
OPT_STRING(0, "setup-filter", &record.filter_action, "pin|unpin",
"BPF filter action"),
OPT_END()
};
@ -4086,6 +4089,18 @@ int cmd_record(int argc, const char **argv)
pr_warning("WARNING: --timestamp-filename option is not available in parallel streaming mode.\n");
}
if (rec->filter_action) {
if (!strcmp(rec->filter_action, "pin"))
err = perf_bpf_filter__pin();
else if (!strcmp(rec->filter_action, "unpin"))
err = perf_bpf_filter__unpin();
else {
pr_warning("Unknown BPF filter action: %s\n", rec->filter_action);
err = -EINVAL;
}
goto out_opts;
}
/*
* Allow aliases to facilitate the lookup of symbols for address
* filters. Refer to auxtrace_parse_filters().