Currently, BPF skeleton generation rules (bpf_skel.mak) are evaluated as part of util/Build. However, because LIBPERF_UTIL_IN explicitly depends on the top-level static libbpf archive, Make completely blocked the execution of bpftool bootstrap and skeleton generation until libbpf finished compiling midway through the build. Since bpftool bootstrap compiles its own independent copy of libbpf.a, it does not depend on the top-level libbpf target. Decouple early skeleton tooling generation by attaching bpf-skel-prepare to the umbrella prepare target, exporting CONFIG_PERF_BPF_SKEL to ensure accurate feature propagation. This allows Make to compile bpftool and dump vmlinux.h in the background at build startup, eliminating the initial sub-make startup bottleneck before BPF object compilation while keeping 100% of tooling rules perfectly encapsulated in bpf_skel.mak. Provide an empty fallback target to ensure builds succeed when BPF skeletons are disabled. Tested-by: James Clark Assisted-by: Gemini:gemini-3.1-pro-preview Signed-off-by: Ian Rogers --- tools/perf/Makefile.perf | 8 ++++++-- tools/perf/bpf_skel.mak | 8 ++++++++ 2 files changed, 14 insertions(+), 2 deletions(-) diff --git a/tools/perf/Makefile.perf b/tools/perf/Makefile.perf index ec0e91bedce1..876065a02de6 100644 --- a/tools/perf/Makefile.perf +++ b/tools/perf/Makefile.perf @@ -275,7 +275,7 @@ ifeq ($(PYLINT),1) endif export srctree OUTPUT RM CC CXX RUSTC CLANG LD AR CFLAGS CXXFLAGS RUST_FLAGS V BISON FLEX AWK LIBBPF READELF -export HOSTCC HOSTLD HOSTAR HOSTCFLAGS SHELLCHECK MYPY PYLINT +export HOSTCC HOSTLD HOSTAR HOSTCFLAGS SHELLCHECK MYPY PYLINT CONFIG_PERF_BPF_SKEL include $(srctree)/tools/build/Makefile.include @@ -629,8 +629,12 @@ endif __build-dir = $(subst $(OUTPUT),,$(dir $@)) build-dir = $(or $(__build-dir),.) +bpf-skel-prepare: + $(Q)$(MAKE) -f bpf_skel.mak bpf-skel-prepare + prepare: $(OUTPUT)PERF-VERSION-FILE \ arm64-sysreg-defs \ + bpf-skel-prepare \ $(LIBAPI) \ $(LIBPERF) \ $(LIBSUBCMD) \ @@ -971,7 +975,7 @@ FORCE: .PHONY: all install clean config-clean strip install-gtk .PHONY: shell_compatibility_test please_set_SHELL_PATH_to_a_more_modern_shell -.PHONY: .FORCE-PERF-VERSION-FILE TAGS tags cscope FORCE prepare +.PHONY: .FORCE-PERF-VERSION-FILE TAGS tags cscope FORCE prepare bpf-skel-prepare .PHONY: python_perf_target endif # force_fixdep diff --git a/tools/perf/bpf_skel.mak b/tools/perf/bpf_skel.mak index 30924ad140c4..7704e7e635d8 100644 --- a/tools/perf/bpf_skel.mak +++ b/tools/perf/bpf_skel.mak @@ -15,6 +15,10 @@ ifeq ($(CONFIG_PERF_BPF_SKEL),y) BPFTOOL := $(SKEL_TOOL_TMP_OUT)/bootstrap/bpftool VMLINUX_H := $(SKEL_TOOL_OUT)/vmlinux.h +.PHONY: bpf-skel-prepare +bpf-skel-prepare: $(BPFTOOL) $(VMLINUX_H) + @: + define get_sys_includes $(shell $(1) $(2) -v -E - &1 \ | sed -n '/<...> search starts here:/,/End of search list./{ s| \(/.*\)|-idirafter \1|p }') \ @@ -93,6 +97,10 @@ $(SKEL_OUT)/%.skel.h: $(SKEL_TMP_OUT)/%.bpf.o $(BPFTOOL) .PRECIOUS: $(SKEL_TMP_OUT)/%.bpf.o +else # CONFIG_PERF_BPF_SKEL +.PHONY: bpf-skel-prepare +bpf-skel-prepare: + @: endif # CONFIG_PERF_BPF_SKEL clean: -- 2.54.0.563.g4f69b47b94-goog