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perf record: Update documentation for BPF filters

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Add more description and examples.

Signed-off-by: Namhyung Kim <namhyung@kernel.org>
Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Andi Kleen <ak@linux.intel.com>
Cc: Hao Luo <haoluo@google.com>
Cc: Ian Rogers <irogers@google.com>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: James Clark <james.clark@arm.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Kan Liang <kan.liang@linux.intel.com>
Cc: Leo Yan <leo.yan@linaro.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Ravi Bangoria <ravi.bangoria@amd.com>
Cc: Song Liu <song@kernel.org>
Cc: Stephane Eranian <eranian@google.com>
Cc: bpf@vger.kernel.org
Link: https://lore.kernel.org/r/20230314234237.3008956-2-namhyung@kernel.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
This commit is contained in:
Namhyung Kim 2023-03-14 16:42:37 -07:00 committed by Arnaldo Carvalho de Melo
parent 4310551b76
commit c46bf3bd00
1 changed files with 46 additions and 1 deletions
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47
tools/perf/Documentation/perf-record.txt
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@ -183,7 +183,52 @@ OPTIONS
A BPF filter can access the sample data and make a decision based on the
data. Users need to set an appropriate sample type to use the BPF
filter.
filter. BPF filters need root privilege.
The sample data field can be specified in lower case letter. Multiple
filters can be separated with comma. For example,
--filter 'period > 1000, cpu == 1'
or
--filter 'mem_op == load || mem_op == store, mem_lvl > l1'
The former filter only accept samples with period greater than 1000 AND
CPU number is 1. The latter one accepts either load and store memory
operations but it should have memory level above the L1. Since the
mem_op and mem_lvl fields come from the (memory) data_source, it'd only
work with some events which set the data_source field.
Also user should request to collect that information (with -d option in
the above case). Otherwise, the following message will be shown.
$ sudo perf record -e cycles --filter 'mem_op == load'
Error: cycles event does not have PERF_SAMPLE_DATA_SRC
Hint: please add -d option to perf record.
failed to set filter "BPF" on event cycles with 22 (Invalid argument)
Essentially the BPF filter expression is:
<term> <operator> <value> (("," | "||") <term> <operator> <value>)*
The <term> can be one of:
ip, id, tid, pid, cpu, time, addr, period, txn, weight, phys_addr,
code_pgsz, data_pgsz, weight1, weight2, weight3, ins_lat, retire_lat,
p_stage_cyc, mem_op, mem_lvl, mem_snoop, mem_remote, mem_lock,
mem_dtlb, mem_blk, mem_hops
The <operator> can be one of:
==, !=, >, >=, <, <=, &
The <value> can be one of:
<number> (for any term)
na, load, store, pfetch, exec (for mem_op)
l1, l2, l3, l4, cxl, io, any_cache, lfb, ram, pmem (for mem_lvl)
na, none, hit, miss, hitm, fwd, peer (for mem_snoop)
remote (for mem_remote)
na, locked (for mem_locked)
na, l1_hit, l1_miss, l2_hit, l2_miss, any_hit, any_miss, walk, fault (for mem_dtlb)
na, by_data, by_addr (for mem_blk)
hops0, hops1, hops2, hops3 (for mem_hops)
--exclude-perf::
Don't record events issued by perf itself. This option should follow