Em Fri, Feb 01, 2019 at 03:06:41AM +0000, Changbin Du escreveu: > Add document for how to pass bpf program with perf.
That is a good start, see some comments below. > Signed-off-by: Changbin Du <[email protected]> > --- > 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. A 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 variant perf events based on section The BPFa various > + names. > + > + When passing '.c', perf searches installed LLVM to compile it into a > + object file first. Optional clang options can be pased by option an > + '--clang-opt'. > + > + perf record --clang-opt "-DLINUX_VERSION_CODE=0x50000" \ > + -e ./tests/bpf-script-example.c > + > + Note: '--clang-opt' must place before '--event'. Please mention ~/.perfconfig, that needs a section in the tools/perf/Documentation/perf-config.txt, for instance I have right now: [root@quaco ~]# cat ~/.perfconfig [llvm] dump-obj = true clang-opt = -g The 'clang-opt' is the same as the command line arg you documented above, dump object may be used to update a .o file, like: [root@quaco ~]# vim /home/acme/git/perf/tools/perf/examples/bpf/augmented_raw_syscalls.c # Do some changes, save [root@quaco ~]# perf record -e /home/acme/git/perf/tools/perf/examples/bpf/augmented_raw_syscalls.c sleep 1 LLVM: dumping /home/acme/git/perf/tools/perf/examples/bpf/augmented_raw_syscalls.o [ perf record: Woken up 1 times to write data ] [ perf record: Captured and wrote 0.023 MB perf.data ] [root@quaco ~]# And if you are up to documenting the remaining features, which I'd encourage you, please take a look at: tools/perf/util/llvm-utils.c In the perf_llvm_config function. there are more things that needs documenting, and doing a: git blame tools/perf/util/llvm-utils.c Helps in getting the needed explanations, for instance, the original patch adding the .perfconfig section was this: git show aa61fd05ca796 And it has, for instance, among others: # kbuild directory. If not set, use /lib/modules/`uname -r`/build. # If set to "" deliberately, skip kernel header auto-detector. kbuild-dir = "/path/to/kernel/build" # Options passed to 'make' when detecting kernel header options. kbuild-opts = "ARCH=x86_64" Thanks for working on documenting these features! - Arnaldo > + > - 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 -- - Arnaldo
