[PATCH update] perf build: Use feature dump file for build-test

[Wang Nan]

To prevent feature check run too many times, this patch utilizes
previous introduced feature-dump make target and FEATURES_DUMP
variable, makes sure the feature checkers run only once when doing
build-test for normal test cases.

However, since standard users doesn't reuse features dump result, we'd
better give an option to check their behaviors. The above feature
should be used to make build-test faster only. Only utilize it for
build-test.

Signed-off-by: Wang Nan <wangnan0@xxxxxxxxxx>
Cc: Jiri Olsa <jolsa@xxxxxxxxxx>
Cc: Arnaldo Carvalho de Melo <acme@xxxxxxxxxx>
Cc: Namhyung Kim <namhyung@xxxxxxxxxx>
---
 tools/perf/Makefile   |  2 +-
 tools/perf/tests/make | 33 +++++++++++++++++++++++++++++++++
 2 files changed, 34 insertions(+), 1 deletion(-)

diff --git a/tools/perf/Makefile b/tools/perf/Makefile
index dcd9a70..e4ff0bd 100644
--- a/tools/perf/Makefile
+++ b/tools/perf/Makefile
@@ -78,7 +78,7 @@ clean:
 # The build-test target is not really parallel, don't print the jobs info:
 #
 build-test:
-	@$(MAKE) SHUF=1 -f tests/make --no-print-directory
+	@$(MAKE) SHUF=1 -f tests/make REUSE_FEATURES_DUMP=1 --no-print-directory
 
 #
 # All other targets get passed through:
diff --git a/tools/perf/tests/make b/tools/perf/tests/make
index f918015..7f663f4 100644
--- a/tools/perf/tests/make
+++ b/tools/perf/tests/make
@@ -15,6 +15,7 @@ else
 PERF := .
 PERF_O := $(PERF)
 O_OPT :=
+FULL_O := $(shell readlink -f $(PERF_O) || echo $(PERF_O))
 
 ifneq ($(O),)
   FULL_O := $(shell readlink -f $(O) || echo $(O))
@@ -313,11 +314,43 @@ make_kernelsrc_tools:
 	(make -C ../../tools $(PARALLEL_OPT) $(K_O_OPT) perf) > $@ 2>&1 && \
 	test -x $(KERNEL_O)/tools/perf/perf && rm -f $@ || (cat $@ ; false)
 
+FEATURES_DUMP_FILE := $(FULL_O)/BUILD_TEST_FEATURE_DUMP
+FEATURES_DUMP_FILE_STATIC := $(FULL_O)/BUILD_TEST_FEATURE_DUMP_STATIC
+
 all: $(run) $(run_O) tarpkg make_kernelsrc make_kernelsrc_tools
 	@echo OK
+	@rm -f $(FEATURES_DUMP_FILE) $(FEATURES_DUMP_FILE_STATIC)
 
 out: $(run_O)
 	@echo OK
+	@rm -f $(FEATURES_DUMP_FILE) $(FEATURES_DUMP_FILE_STATIC)
+
+ifeq ($(REUSE_FEATURES_DUMP),1)
+$(FEATURES_DUMP_FILE):
+	$(call clean)
+	@cmd="cd $(PERF) && make FEATURE_DUMP_COPY=$@ $(O_OPT) feature-dump"; \
+	echo "- $@: $$cmd" && echo $$cmd && \
+	( eval $$cmd ) > /dev/null 2>&1
+
+$(FEATURES_DUMP_FILE_STATIC):
+	$(call clean)
+	@cmd="cd $(PERF) && make FEATURE_DUMP_COPY=$@ $(O_OPT) LDFLAGS='-static' feature-dump"; \
+	echo "- $@: $$cmd" && echo $$cmd && \
+	( eval $$cmd ) > /dev/null 2>&1
+
+# Add feature dump dependency for run/run_O targets
+$(foreach t,$(run) $(run_O),$(eval \
+	$(t): $(if $(findstring make_static,$(t)),\
+		$(FEATURES_DUMP_FILE_STATIC),\
+		$(FEATURES_DUMP_FILE))))
+
+# Append 'FEATURES_DUMP=' option to all test cases. For example:
+# make_no_libbpf: NO_LIBBPF=1  --> NO_LIBBPF=1 FEATURES_DUMP=/a/b/BUILD_TEST_FEATURE_DUMP
+# make_static: LDFLAGS=-static --> LDFLAGS=-static FEATURES_DUMP=/a/b/BUILD_TEST_FEATURE_DUMP_STATIC
+$(foreach t,$(run),$(if $(findstring make_static,$(t)),\
+			$(eval $(t) := $($(t)) FEATURES_DUMP=$(FEATURES_DUMP_FILE_STATIC)),\
+			$(eval $(t) := $($(t)) FEATURES_DUMP=$(FEATURES_DUMP_FILE))))
+endif
 
 .PHONY: all $(run) $(run_O) tarpkg clean make_kernelsrc make_kernelsrc_tools
 endif # ifndef MK
-- 
1.8.3.4