From 423216ed3273dae18c347ce52c5ecc193cfdd4e5 Mon Sep 17 00:00:00 2001 From: Anton Blanchard Date: Tue, 16 Sep 2014 10:49:14 +1000 Subject: [PATCH] powerpc: Use CONFIG_ARCH_HAS_FAST_MULTIPLIER I ran some tests to compare hash_64 using shifts and multiplies. The results: POWER6: ~2x slower POWER7: ~2x faster POWER8: ~2x faster Now we have a proper config option, select CONFIG_ARCH_HAS_FAST_MULTIPLIER on POWER7 and POWER8. Signed-off-by: Anton Blanchard Signed-off-by: Michael Ellerman --- arch/powerpc/platforms/Kconfig.cputype | 2 ++ 1 file changed, 2 insertions(+) diff --git a/arch/powerpc/platforms/Kconfig.cputype b/arch/powerpc/platforms/Kconfig.cputype index 26703be24cf9..35ae7ec392ec 100644 --- a/arch/powerpc/platforms/Kconfig.cputype +++ b/arch/powerpc/platforms/Kconfig.cputype @@ -116,10 +116,12 @@ config POWER6_CPU config POWER7_CPU bool "POWER7" depends on PPC_BOOK3S_64 + select ARCH_HAS_FAST_MULTIPLIER config POWER8_CPU bool "POWER8" depends on PPC_BOOK3S_64 + select ARCH_HAS_FAST_MULTIPLIER config E5500_CPU bool "Freescale e5500" -- 2.20.1