[PATCH] perf record: Add doc for bpf event selection

From: Changbin Du
Date: Thu Jan 31 2019 - 22:07:01 EST


Add document for how to pass bpf program with perf.

Signed-off-by: Changbin Du <changbin.du@xxxxxxxxx>
---
tools/perf/Documentation/perf-record.txt | 13 +++++++++++++
1 file changed, 13 insertions(+)

diff --git a/tools/perf/Documentation/perf-record.txt b/tools/perf/Documentation/perf-record.txt
index d232b13ea713..0925d987cad0 100644
--- a/tools/perf/Documentation/perf-record.txt
+++ b/tools/perf/Documentation/perf-record.txt
@@ -88,6 +88,19 @@ OPTIONS
If you want to profile write accesses in [0x1000~1008), just set
'mem:0x1000/8:w'.

+ - a bpf source file or object file to select events by a bpf program.
+ The bpf program can attach to variant perf events based on section
+ names.
+
+ When passing '.c', perf searches installed LLVM to compile it into
+ object file first. Optional clang options can be pased by option
+ '--clang-opt'.
+
+ perf record --clang-opt "-DLINUX_VERSION_CODE=0x50000" \
+ -e ./tests/bpf-script-example.c
+
+ Note: '--clang-opt' must place before '--event'.
+
- a group of events surrounded by a pair of brace ("{event1,event2,...}").
Each event is separated by commas and the group should be quoted to
prevent the shell interpretation. You also need to use --group on
--
2.17.1