Re: [RFC 1/2] perf: support build BPF skeletons with perf

[Song Liu]

> On Nov 24, 2020, at 11:51 AM, Jiri Olsa <jolsa@xxxxxxxxxx> wrote:
> 
> On Wed, Nov 18, 2020 at 08:50:45PM -0800, Song Liu wrote:
> 
> SNIP
> 
>> +
>> +$(TMP_OUTPUT):
>> +	$(call msg,MKDIR,$@)
>> +	$(Q)mkdir -p $(TMP_OUTPUT)
>> +
>> +$(TMP_OUTPUT)/vmlinux.h: $(VMLINUX_BTF_PATH) | $(TMP_OUTPUT) $(BPFTOOL)
>> +	$(call msg,GEN,$@)
>> +	$(Q)if [ ! -e "$(VMLINUX_BTF_PATH)" ] ; then \
>> +		echo "Couldn't find kernel BTF; set VMLINUX_BTF to"	       \
>> +			"specify its location." >&2;			       \
>> +		exit 1;\
>> +	fi
>> +	$(Q)$(BPFTOOL) btf dump file $(VMLINUX_BTF_PATH) format c > $@
>> +
>> +$(BPFOBJ): $(wildcard $(LIBBPF_SRC)/*.[ch] $(LIBBPF_SRC)/Makefile) | $(TMP_OUTPUT)
>> +	$(Q)$(MAKE) $(submake_extras) -C $(LIBBPF_SRC)			       \
>> +		    OUTPUT=$(abspath $(dir $@))/ $(abspath $@)
>> +
>> +$(DEFAULT_BPFTOOL): | $(TMP_OUTPUT)
>> +	$(Q)$(MAKE) $(submake_extras) -C ../../../bpf/bpftool		      \
>> +		    prefix= OUTPUT=$(TMP_OUTPUT)/ DESTDIR=$(TMP_OUTPUT) install
> 
> could we build just the bootstrap version of bpftool?
> should be enough for skeleton and vmlinux.h dump, no?
> 

Yeah, that should work. I thought about it, but didn't try that hard. 

Song