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Commit 55fa8b8c authored by Changbin Du's avatar Changbin Du Committed by Arnaldo Carvalho de Melo
Browse files

perf tools: Add documentation for BPF event selection 



Add documentation for how to pass a BPF program as a perf event.

Signed-off-by: default avatarChangbin Du <changbin.du@gmail.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Link: http://lkml.kernel.org/r/20190201134651.12373-1-changbin.du@gmail.com


Signed-off-by: default avatarArnaldo Carvalho de Melo <acme@redhat.com>
parent dbd2a1d5

tools/perf/Documentation/perf-config.txt

+31 −0
Original line number Diff line number Diff line
@@ -120,6 +120,10 @@ Given a $HOME/.perfconfig like this: 
		children = true

		group = true



	[llvm]

		dump-obj = true

		clang-opt = -g



You can hide source code of annotate feature setting the config to false with



	% perf config annotate.hide_src_code=true
@@ -553,6 +557,33 @@ trace.*:: 
	trace.show_zeros::

		Do not suppress syscall arguments that are equal to zero.



llvm.*::

	llvm.clang-path::

		Path to clang. If omit, search it from $PATH.



	llvm.clang-bpf-cmd-template::

		Cmdline template. Below lines show its default value. Environment

		variable is used to pass options.

		"$CLANG_EXEC -D__KERNEL__ $CLANG_OPTIONS $KERNEL_INC_OPTIONS \

		-Wno-unused-value -Wno-pointer-sign -working-directory \

		$WORKING_DIR  -c $CLANG_SOURCE -target bpf -O2 -o -"



	llvm.clang-opt::

		Options passed to clang.



	llvm.kbuild-dir::

		kbuild directory. If not set, use /lib/modules/`uname -r`/build.

		If set to "" deliberately, skip kernel header auto-detector.



	llvm.kbuild-opts::

		Options passed to 'make' when detecting kernel header options.



	llvm.dump-obj::

		Enable perf dump BPF object files compiled by LLVM.



	llvm.opts::

		Options passed to llc.



SEE ALSO

--------

linkperf:perf[1]

tools/perf/Documentation/perf-record.txt

+14 −0
Original line number Diff line number Diff line
@@ -88,6 +88,20 @@ OPTIONS 
          If you want to profile write accesses in [0x1000~1008), just set

          'mem:0x1000/8:w'.



        - a BPF source file (ending in .c) or a precompiled object file (ending

          in .o) selects one or more BPF events.

          The BPF program can attach to various perf events based on the ELF section

          names.



          When processing a '.c' file, perf searches an installed LLVM to compile it

          into an object file first. Optional clang options can be passed via the

          '--clang-opt' command line option, e.g.:



            perf record --clang-opt "-DLINUX_VERSION_CODE=0x50000" \

                        -e tests/bpf-script-example.c



          Note: '--clang-opt' must be placed before '--event/-e'.



	- 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