diff options
| author | Arnd Bergmann <arnd@arndb.de> | 2007-09-15 04:21:57 +0400 |
|---|---|---|
| committer | Paul Mackerras <paulus@samba.org> | 2007-09-22 08:49:22 +0400 |
| commit | 3164cccdc0e6e16eb9797586aaa8d1f759799c01 (patch) | |
| tree | 5685db34bfa546cefcd1f6fc0cbbac8bd11945bb | |
| parent | fb8299ed31d474248c2028ab8393462841cc9b0b (diff) | |
| download | linux-3164cccdc0e6e16eb9797586aaa8d1f759799c01.tar.xz | |
[POWERPC] add Kconfig option for optimizing for cell
Since the PPE on cell is an in-order core, it suffers significantly
from wrong instruction scheduling. This adds a Kconfig option that
enables passing -mtune=cell to gcc in order to generate object
code that runs well on cell.
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Paul Mackerras <paulus@samba.org>
| -rw-r--r-- | arch/powerpc/Makefile | 4 | ||||
| -rw-r--r-- | arch/powerpc/platforms/Kconfig.cputype | 12 |
2 files changed, 16 insertions, 0 deletions
diff --git a/arch/powerpc/Makefile b/arch/powerpc/Makefile index 6015a92bc2a0..87aff5372d6e 100644 --- a/arch/powerpc/Makefile +++ b/arch/powerpc/Makefile @@ -92,6 +92,10 @@ else endif endif +ifeq ($(CONFIG_TUNE_CELL),y) + CFLAGS += $(call cc-option,-mtune=cell) +endif + # No AltiVec instruction when building kernel CFLAGS += $(call cc-option,-mno-altivec) diff --git a/arch/powerpc/platforms/Kconfig.cputype b/arch/powerpc/platforms/Kconfig.cputype index 86eb4cf31f0b..4c315be25015 100644 --- a/arch/powerpc/platforms/Kconfig.cputype +++ b/arch/powerpc/platforms/Kconfig.cputype @@ -71,6 +71,18 @@ config POWER4 depends on PPC64 def_bool y +config TUNE_CELL + bool "Optimize for Cell Broadband Engine" + depends on PPC64 + help + Cause the compiler to optimize for the PPE of the Cell Broadband + Engine. This will make the code run considerably faster on Cell + but somewhat slower on other machines. This option only changes + the scheduling of instructions, not the selection of instructions + itself, so the resulting kernel will keep running on all other + machines. When building a kernel that is supposed to run only + on Cell, you should also select the POWER4_ONLY option. + config 6xx bool |