Commit a43eec304259a6c637f4014a6d4767159b6a3aa3 (bpf: introduce
bpf_perf_event_output() helper) add a helper to enable BPF program
output data to perf ring buffer through a new type of perf event
PERF_COUNT_SW_BPF_OUTPUT. This patch enable perf to create perf
event of that type. Now perf user can use following cmdline to
receive output data from BPF programs:

 # perf record -a -e evt=bpf-output/no-inherit/ \
                  -e ./test_bpf_output.c/maps.bpf-output.event=evt/ ls

 # perf script
        perf 12927 [004] 355971.129276:          0 evt=bpf-output/no-inherit/:  
ffffffff811ed5f1 sys_write
        perf 12927 [004] 355971.129279:          0 evt=bpf-output/no-inherit/:  
ffffffff811ed5f1 sys_write
        ...

Signed-off-by: Wang Nan <wangn...@huawei.com>
Cc: Alexei Starovoitov <a...@plumgrid.com>
Cc: Arnaldo Carvalho de Melo <a...@redhat.com>
Cc: Brendan Gregg <brendan.d.gr...@gmail.com>
Cc: David S. Miller <da...@davemloft.net>
---
 tools/perf/util/evsel.c        | 6 ++++++
 tools/perf/util/parse-events.c | 4 ++++
 tools/perf/util/parse-events.l | 1 +
 3 files changed, 11 insertions(+)

diff --git a/tools/perf/util/evsel.c b/tools/perf/util/evsel.c
index 397fb4e..f01defb 100644
--- a/tools/perf/util/evsel.c
+++ b/tools/perf/util/evsel.c
@@ -224,6 +224,12 @@ struct perf_evsel *perf_evsel__new_idx(struct 
perf_event_attr *attr, int idx)
        if (evsel != NULL)
                perf_evsel__init(evsel, attr, idx);
 
+       if ((evsel->attr.type == PERF_TYPE_SOFTWARE) &&
+           (evsel->attr.config == PERF_COUNT_SW_BPF_OUTPUT)) {
+               evsel->attr.sample_type |= PERF_SAMPLE_RAW;
+               evsel->attr.sample_period = 1;
+       }
+
        return evsel;
 }
 
diff --git a/tools/perf/util/parse-events.c b/tools/perf/util/parse-events.c
index b98a82c..6ac39d6 100644
--- a/tools/perf/util/parse-events.c
+++ b/tools/perf/util/parse-events.c
@@ -124,6 +124,10 @@ struct event_symbol event_symbols_sw[PERF_COUNT_SW_MAX] = {
                .symbol = "dummy",
                .alias  = "",
        },
+       [PERF_COUNT_SW_BPF_OUTPUT] = {
+               .symbol = "bpf-output",
+               .alias  = "",
+       },
 };
 
 #define __PERF_EVENT_FIELD(config, name) \
diff --git a/tools/perf/util/parse-events.l b/tools/perf/util/parse-events.l
index 1fa8e0b..f4ed79b 100644
--- a/tools/perf/util/parse-events.l
+++ b/tools/perf/util/parse-events.l
@@ -249,6 +249,7 @@ cpu-migrations|migrations                   { return 
sym(yyscanner, PERF_TYPE_SOFTWARE, PERF_COU
 alignment-faults                               { return sym(yyscanner, 
PERF_TYPE_SOFTWARE, PERF_COUNT_SW_ALIGNMENT_FAULTS); }
 emulation-faults                               { return sym(yyscanner, 
PERF_TYPE_SOFTWARE, PERF_COUNT_SW_EMULATION_FAULTS); }
 dummy                                          { return sym(yyscanner, 
PERF_TYPE_SOFTWARE, PERF_COUNT_SW_DUMMY); }
+bpf-output                                     { return sym(yyscanner, 
PERF_TYPE_SOFTWARE, PERF_COUNT_SW_BPF_OUTPUT); }
 
        /*
         * We have to handle the kernel PMU event 
cycles-ct/cycles-t/mem-loads/mem-stores separately.
-- 
1.8.3.4

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