> On Dec 3, 2020, at 3:31 PM, Jiri Olsa <[email protected]> wrote:
>
> On Wed, Dec 02, 2020 at 01:37:08AM -0800, Song Liu wrote:
>> BPF programs are useful in perf to profile BPF programs. BPF skeleton is
>> by far the easiest way to write BPF tools. Enable building BPF skeletons
>> in util/bpf_skel. A dummy bpf skeleton is added. More bpf skeletons will
>> be added for different use cases.
>>
>> Signed-off-by: Song Liu <[email protected]>
>>
[...]
>> index 97cbfb31b7625..4eeeabbaa2947 100644
>> --- a/tools/build/Makefile.feature
>> +++ b/tools/build/Makefile.feature
>> @@ -99,7 +99,9 @@ FEATURE_TESTS_EXTRA := \
>> clang \
>> libbpf \
>> libpfm4 \
>> - libdebuginfod
>> + libdebuginfod \
>> + clang-bpf-co-re
>
> do not use tabs in here
Will fix.
>
>> +
>>
>> FEATURE_TESTS ?= $(FEATURE_TESTS_BASIC)
>>
>> diff --git a/tools/perf/Makefile.config b/tools/perf/Makefile.config
>> index ce8516e4de34f..c8ff82b4fc1b2 100644
>> --- a/tools/perf/Makefile.config
>> +++ b/tools/perf/Makefile.config
>> @@ -621,6 +621,16 @@ ifndef NO_LIBBPF
>> endif
>> endif
>>
>> +$(call feature_check,clang-bpf-co-re)
>> +ifeq ($(feature-clang-bpf-co-re), 0)
>> + undefine BUILD_BPF_SKEL
>
> we compile with 'make BUILD_BPF_SKEL=1' so we should fail here
> with the standard 'please install..' message we use
Yeah, that makes sense. Will fix it in the next version.
>
>> +endif
>> +
>> +ifdef BUILD_BPF_SKEL
>> + $(call detected,CONFIG_PERF_BPF_SKEL)
>> + CFLAGS += -DBUILD_BPF_SKEL
>> +endif
>> +
>> dwarf-post-unwind := 1
>> dwarf-post-unwind-text := BUG
>>
>> diff --git a/tools/perf/Makefile.perf b/tools/perf/Makefile.perf
>> index 7ce3f2e8b9c74..f46f0cd012b2d 100644
>> --- a/tools/perf/Makefile.perf
>> +++ b/tools/perf/Makefile.perf
>> @@ -126,6 +126,8 @@ include ../scripts/utilities.mak
>> #
>> # Define NO_LIBDEBUGINFOD if you do not want support debuginfod
>> #
>> +# Define BUILD_BPF_SKEL to enable BPF skeletons
>> +#
>>
>> # As per kernel Makefile, avoid funny character set dependencies
>> unexport LC_ALL
>> @@ -178,6 +180,8 @@ LD += $(EXTRA_LDFLAGS)
>> HOSTCC ?= gcc
>> HOSTLD ?= ld
>> HOSTAR ?= ar
>> +CLANG ?= clang
>
> please keep the indent with other ?= when possible
Will fix.
>
>> +LLVM_STRIP ?= llvm-strip
>>
>> PKG_CONFIG = $(CROSS_COMPILE)pkg-config
>> LLVM_CONFIG ?= llvm-config
>> @@ -735,7 +739,8 @@ prepare: $(OUTPUT)PERF-VERSION-FILE
>> $(OUTPUT)common-cmds.h archheaders $(drm_ioc
>> $(x86_arch_prctl_code_array) \
>> $(rename_flags_array) \
>> $(arch_errno_name_array) \
>> - $(sync_file_range_arrays)
>> + $(sync_file_range_arrays) \
>> + bpf-skel
>>
>> $(OUTPUT)%.o: %.c prepare FORCE
>> $(Q)$(MAKE) -f $(srctree)/tools/build/Makefile.build dir=$(build-dir) $@
>> @@ -1008,7 +1013,44 @@ config-clean:
>> python-clean:
>> $(python-clean)
>>
>> -clean:: $(LIBTRACEEVENT)-clean $(LIBAPI)-clean $(LIBBPF)-clean
>> $(LIBSUBCMD)-clean $(LIBPERF)-clean config-clean fixdep-clean python-clean
>> +SKEL_OUT := $(abspath util/bpf_skel)
>> +SKEL_TMP_OUT := $(abspath util/bpf_skel/.tmp)
>
> hum, actualy we use $(OUTPUT) and if it's not defined we build
> directly in the tree, this should follow the same
Good catch! I tested with OUTPUT in earlier version, missed it
later on. Will fix it in the next version.
>> +SKELETONS := $(SKEL_OUT)/dummy.skel.h
>> +
>> +ifdef BUILD_BPF_SKEL
>> +BPFTOOL := $(SKEL_TMP_OUT)/bpftool-bootstrap
>> +LIBBPF_SRC := $(abspath ../lib/bpf)
>> +BPF_INCLUDE := -I$(SKEL_TMP_OUT)/..
>> +submake_extras := feature_display=0
>
> there's no need for the variable, is there?
> also why do we want to hide it?
I guess no need to hide it. I copied this pattern from bpftool.
Let me remove it in v2.
Thanks,
Song
