Evaluate LDFLAGS_BUILD_ID (which involves invoking the compiler) only
once instead of over and over.
This provides a 20% reduction in null build time with x86 allnoconfig on
my machine:
$ make -j8 && perf stat -r5 make -j8
Before: 1,086617617 seconds time elapsed ( +- 0,37% )
After: 0,864487173 seconds time elapsed ( +- 0,35% )
Signed-off-by: Rabin Vincent <ra...@rab.in>
---
Makefile | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/Makefile b/Makefile
index 6471f20ca400..91baa282f3fa 100644
--- a/Makefile
+++ b/Makefile
@@ -814,7 +814,7 @@ KBUILD_AFLAGS += $(ARCH_AFLAGS) $(KAFLAGS)
KBUILD_CFLAGS += $(ARCH_CFLAGS) $(KCFLAGS)
# Use --build-id when available.
-LDFLAGS_BUILD_ID = $(patsubst -Wl$(comma)%,%,\
+LDFLAGS_BUILD_ID := $(patsubst -Wl$(comma)%,%,\
$(call cc-ldoption, -Wl$(comma)--build-id,))
KBUILD_LDFLAGS_MODULE += $(LDFLAGS_BUILD_ID)
LDFLAGS_vmlinux += $(LDFLAGS_BUILD_ID)
--
2.8.1
