Make use of -M compiler options when building .test.o objects to generate .d files and avoid re-building all tests every time. Previously, if a single test bpf program under selftests/bpf/progs/*.c has changed, make would rebuild all the *.bpf.o, *.skel.h and *.test.o objects, which is a lot of unnecessary work. A typical dependency chain is: progs/x.c -> x.bpf.o -> x.skel.h -> x.test.o -> trunner_binary However for many tests it's not a 1:1 mapping by name, and so far %.test.o have been simply dependent on all %.skel.h files, and %.skel.h files on all %.bpf.o objects. Avoid full rebuilds by instructing the compiler (via -MMD) to produce *.d files with real dependencies, and appropriately including them. Exploit make feature that rebuilds included makefiles if they were changed by setting %.test.d as prerequisite for %.test.o files. A couple of examples of compilation time speedup (after the first clean build): $ touch progs/verifier_and.c && time make -j8 Before: real 0m16.651s After: real 0m2.245s $ touch progs/read_vsyscall.c && time make -j8 Before: real 0m15.743s After: real 0m1.575s A drawback of this change is that now there is an overhead due to make processing lots of .d files, which potentially may slow down unrelated targets. However a time to make all from scratch hasn't changed significantly: $ make clean && time make -j8 Before: real 1m31.148s After: real 1m30.309s Suggested-by: Eduard Zingerman <eddyz87@xxxxxxxxx> Signed-off-by: Ihor Solodrai <ihor.solodrai@xxxxx> --- v1 -> v2: Make %.test.d prerequisite order only --- tools/testing/selftests/bpf/.gitignore | 1 + tools/testing/selftests/bpf/Makefile | 41 +++++++++++++++++++------- 2 files changed, 31 insertions(+), 11 deletions(-) diff --git a/tools/testing/selftests/bpf/.gitignore b/tools/testing/selftests/bpf/.gitignore index 5025401323af..4e4aae8aa7ec 100644 --- a/tools/testing/selftests/bpf/.gitignore +++ b/tools/testing/selftests/bpf/.gitignore @@ -31,6 +31,7 @@ test_tcp_check_syncookie_user test_sysctl xdping test_cpp +*.d *.subskel.h *.skel.h *.lskel.h diff --git a/tools/testing/selftests/bpf/Makefile b/tools/testing/selftests/bpf/Makefile index dd49c1d23a60..254d92a3b791 100644 --- a/tools/testing/selftests/bpf/Makefile +++ b/tools/testing/selftests/bpf/Makefile @@ -477,7 +477,8 @@ xsk_xdp_progs.skel.h-deps := xsk_xdp_progs.bpf.o xdp_hw_metadata.skel.h-deps := xdp_hw_metadata.bpf.o xdp_features.skel.h-deps := xdp_features.bpf.o -LINKED_BPF_SRCS := $(patsubst %.bpf.o,%.c,$(foreach skel,$(LINKED_SKELS),$($(skel)-deps))) +LINKED_BPF_OBJS := $(foreach skel,$(LINKED_SKELS),$($(skel)-deps)) +LINKED_BPF_SRCS := $(patsubst %.bpf.o,%.c,$(LINKED_BPF_OBJS)) # Set up extra TRUNNER_XXX "temporary" variables in the environment (relies on # $eval()) and pass control to DEFINE_TEST_RUNNER_RULES. @@ -556,7 +557,11 @@ $(TRUNNER_BPF_LSKELS): %.lskel.h: %.bpf.o $(BPFTOOL) | $(TRUNNER_OUTPUT) $(Q)$$(BPFTOOL) gen skeleton -L $$(<:.o=.llinked3.o) name $$(notdir $$(<:.bpf.o=_lskel)) > $$@ $(Q)rm -f $$(<:.o=.llinked1.o) $$(<:.o=.llinked2.o) $$(<:.o=.llinked3.o) -$(TRUNNER_BPF_SKELS_LINKED): $(TRUNNER_BPF_OBJS) $(BPFTOOL) | $(TRUNNER_OUTPUT) +$(LINKED_BPF_OBJS): %: $(TRUNNER_OUTPUT)/% + +# .SECONDEXPANSION here allows to correctly expand %-deps variables as prerequisites +.SECONDEXPANSION: +$(TRUNNER_BPF_SKELS_LINKED): $(TRUNNER_OUTPUT)/%: $$$$(%-deps) $(BPFTOOL) | $(TRUNNER_OUTPUT) $$(call msg,LINK-BPF,$(TRUNNER_BINARY),$$(@:.skel.h=.bpf.o)) $(Q)$$(BPFTOOL) gen object $$(@:.skel.h=.linked1.o) $$(addprefix $(TRUNNER_OUTPUT)/,$$($$(@F)-deps)) $(Q)$$(BPFTOOL) gen object $$(@:.skel.h=.linked2.o) $$(@:.skel.h=.linked1.o) @@ -566,6 +571,14 @@ $(TRUNNER_BPF_SKELS_LINKED): $(TRUNNER_BPF_OBJS) $(BPFTOOL) | $(TRUNNER_OUTPUT) $(Q)$$(BPFTOOL) gen skeleton $$(@:.skel.h=.linked3.o) name $$(notdir $$(@:.skel.h=)) > $$@ $(Q)$$(BPFTOOL) gen subskeleton $$(@:.skel.h=.linked3.o) name $$(notdir $$(@:.skel.h=)) > $$(@:.skel.h=.subskel.h) $(Q)rm -f $$(@:.skel.h=.linked1.o) $$(@:.skel.h=.linked2.o) $$(@:.skel.h=.linked3.o) + +# When the compiler generates a %.d file, only skel basenames (not +# full paths) are specified as prerequisites for corresponding %.o +# file. This target makes %.skel.h basename dependent on full paths, +# linking generated %.d dependency with actual %.skel.h files. +$(notdir %.skel.h): $(TRUNNER_OUTPUT)/%.skel.h + @true + endif # ensure we set up tests.h header generation rule just once @@ -583,14 +596,20 @@ endif # Note: we cd into output directory to ensure embedded BPF object is found $(TRUNNER_TEST_OBJS): $(TRUNNER_OUTPUT)/%.test.o: \ $(TRUNNER_TESTS_DIR)/%.c \ - $(TRUNNER_EXTRA_HDRS) \ - $(TRUNNER_BPF_OBJS) \ - $(TRUNNER_BPF_SKELS) \ - $(TRUNNER_BPF_LSKELS) \ - $(TRUNNER_BPF_SKELS_LINKED) \ - $$(BPFOBJ) | $(TRUNNER_OUTPUT) + | $(TRUNNER_OUTPUT)/%.test.d $$(call msg,TEST-OBJ,$(TRUNNER_BINARY),$$@) - $(Q)cd $$(@D) && $$(CC) -I. $$(CFLAGS) -c $(CURDIR)/$$< $$(LDLIBS) -o $$(@F) + $(Q)cd $$(@D) && $$(CC) -I. $$(CFLAGS) -MMD -MT $$@ -c $(CURDIR)/$$< $$(LDLIBS) -o $$(@F) + +$(TRUNNER_TEST_OBJS:.o=.d): $(TRUNNER_OUTPUT)/%.test.d: \ + $(TRUNNER_TESTS_DIR)/%.c \ + $(TRUNNER_EXTRA_HDRS) \ + $(TRUNNER_BPF_SKELS) \ + $(TRUNNER_BPF_LSKELS) \ + $(TRUNNER_BPF_SKELS_LINKED) \ + $$(BPFOBJ) | $(TRUNNER_OUTPUT) + +include $(wildcard $(TRUNNER_TEST_OBJS:.o=.d)) + $(TRUNNER_EXTRA_OBJS): $(TRUNNER_OUTPUT)/%.o: \ %.c \ @@ -768,8 +787,8 @@ $(OUTPUT)/uprobe_multi: uprobe_multi.c EXTRA_CLEAN := $(SCRATCH_DIR) $(HOST_SCRATCH_DIR) \ prog_tests/tests.h map_tests/tests.h verifier/tests.h \ - feature bpftool \ - $(addprefix $(OUTPUT)/,*.o *.skel.h *.lskel.h *.subskel.h \ + feature bpftool \ + $(addprefix $(OUTPUT)/,*.o *.d *.skel.h *.lskel.h *.subskel.h \ no_alu32 cpuv4 bpf_gcc bpf_testmod.ko \ bpf_test_no_cfi.ko \ liburandom_read.so) -- 2.34.1
