-Os is enforced here, based on the test result of decompression time
below, slightly faster than -O2.
But further tests with UA show that using -O2 will be the right choice
especially in the case of the unaligned access enabled and the gap,
few counts in the normal decompression mode is small enough to remove -Os.
Decompression Time(counts)
Normal UA enabled
-Os 6717 3447
-O2 6720 2728
Note: ARM v7, Kernel 3.4
counter freq. = 32768 HZ
UA(Unaligned Access)
gcc version 4.6.2
Signed-off-by: Kyungsik Lee <kyungsik.lee@xxxxxxx>
Cc: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
Cc: Russell King <rmk@xxxxxxxxxxxxxxxx>
Cc: Borislav Petkov <bp@xxxxxxxxx>
Cc: Florian Fainelli <florian@xxxxxxxxxxx>
Cc: Yann Collet <yann.collet.73@xxxxxxxxx>
---
arch/arm/boot/compressed/Makefile | 3 ---
1 file changed, 3 deletions(-)
diff --git a/arch/arm/boot/compressed/Makefile b/arch/arm/boot/compressed/Makefile
index 001a13a..198a4ad 100644
--- a/arch/arm/boot/compressed/Makefile
+++ b/arch/arm/boot/compressed/Makefile
@@ -27,9 +27,6 @@ OBJS += misc.o decompress.o
ifeq ($(CONFIG_DEBUG_UNCOMPRESS),y)
OBJS += debug.o
endif
-ifeq ($(CONFIG_KERNEL_LZ4),y)
-CFLAGS_decompress.o := -Os
-endif
FONTC = $(srctree)/drivers/video/console/font_acorn_8x8.c
# string library code (-Os is enforced to keep it much smaller)
--
1.8.1.1
--
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