Commit-ID: 55fa8b8c0a37618c94df38d50d6871cb3e755ad2 Gitweb: https://git.kernel.org/tip/55fa8b8c0a37618c94df38d50d6871cb3e755ad2 Author: Changbin Du <changbin...@gmail.com> AuthorDate: Fri, 1 Feb 2019 21:46:51 +0800 Committer: Arnaldo Carvalho de Melo <a...@redhat.com> CommitDate: Wed, 6 Feb 2019 10:00:40 -0300
perf tools: Add documentation for BPF event selection Add documentation for how to pass a BPF program as a perf event. Signed-off-by: Changbin Du <changbin...@gmail.com> Cc: Jiri Olsa <jo...@redhat.com> Cc: Namhyung Kim <namhy...@kernel.org> Cc: Peter Zijlstra <pet...@infradead.org> Link: http://lkml.kernel.org/r/20190201134651.12373-1-changbin...@gmail.com Signed-off-by: Arnaldo Carvalho de Melo <a...@redhat.com> --- tools/perf/Documentation/perf-config.txt | 31 +++++++++++++++++++++++++++++++ tools/perf/Documentation/perf-record.txt | 14 ++++++++++++++ 2 files changed, 45 insertions(+) diff --git a/tools/perf/Documentation/perf-config.txt b/tools/perf/Documentation/perf-config.txt index 4ac7775fbc11..86f3dcc15f83 100644 --- a/tools/perf/Documentation/perf-config.txt +++ b/tools/perf/Documentation/perf-config.txt @@ -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] diff --git a/tools/perf/Documentation/perf-record.txt b/tools/perf/Documentation/perf-record.txt index d232b13ea713..02b4aa2621e7 100644 --- a/tools/perf/Documentation/perf-record.txt +++ b/tools/perf/Documentation/perf-record.txt @@ -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
