From: Anton Blanchard <anton@samba.org>
Date: Tue, 16 Sep 2014 00:49:14 +0000 (+1000)
Subject: powerpc: Use CONFIG_ARCH_HAS_FAST_MULTIPLIER
X-Git-Url: http://git.cdn.openwrt.org/?a=commitdiff_plain;h=423216ed3273dae18c347ce52c5ecc193cfdd4e5;p=openwrt%2Fstaging%2Fblogic.git

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 <anton@samba.org>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
---

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"