[RFC PATCH net-next 2/4] perf tools: Introduce bpf-output event

From: Wang Nan
Date: Wed Oct 28 2015 - 07:00:14 EST


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 <wangnan0@xxxxxxxxxx>
Cc: Alexei Starovoitov <ast@xxxxxxxxxxxx>
Cc: Arnaldo Carvalho de Melo <acme@xxxxxxxxxx>
Cc: Brendan Gregg <brendan.d.gregg@xxxxxxxxx>
Cc: David S. Miller <davem@xxxxxxxxxxxxx>
---
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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